Author: Carl Stalhood

VMware Horizon Load Balancing – NetScaler / Citrix ADC

Last Modified: Jul 25, 2024 @ 12:06 pm

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Use this procedure to load balance VMware Unified Access Gateway.

Change Log

Overview

To simplify this post, this post is focused on Unified Access Gateway, which is the replacement for Horizon Security Servers.

For load balancing of other Horizon components:

  • Internal Horizon Connection Servers – This is standard load balancing on SSL_BRIDGE protocol, port 443, and Source IP persistence. See the CLI commands for a sample configuration.
    • If you enabled the Secure Gateways (PCoIP, Blast) on the Connection Servers, then load balance the Connection Servers using the same procedure as load balancing UAGs.

UAG appliances vs Horizon Security Servers

There are two VMware-provided remote access solutions for Horizon View:

Unified Access Gateway appliances are preferred over Horizon Security Servers for the following reasons:

  • No need to pair with internal Connection Servers, which simplifies the configuration.
  • Linux appliance instead of Windows server.
  • Authentication can be offloaded to the Unified Access Gateway. This includes: Smart Cards, RSA, and RADIUS.
  • Blast Extreme Adaptive Transport (BEAT) in Horizon 7.1 and newer only works with Unified Access Gateway 2.9 and newer. Security Server and older Access Points don’t work.
    • VMware Blog Post Deep Dive into VMware Horizon Blast Extreme Adaptive Transport – Blast Extreme Adaptive Transport is enabled by default in VMware Horizon View 7.1 and Horizon Client 4.4. If the clients are connecting from outside the demilitarized zone (DMZ), you would also need to have VMware Unified Access Gateway (not Security Server) to take full advantage of the new transport. The adaptive transport will automatically sense the network for UDP availability and will fallback to legacy Blast TCP if UDP is not available.

Here is a typical Unified Access Gateway architecture:

  • Two Internal Connection Servers – these need to be load balanced on an internal VIP on TCP 443. Internal users connect to the internal VIP.
    • Instructions for load balancing the internal Connection Servers are not detailed in this post. Instead, see the CLI Commands.
  • Two DMZ Unified Access Gateway (Access Point) appliances – these need to be load balanced on a DMZ VIP on several ports. External users connect to the DMZ VIP.
    • Unified Access Gateway appliances connect to the internal Load Balancing VIP for the internal Connection Servers using HTTPS protocol
    • Unified Access Gateway appliances connect directly to Horizon Agents using Blast or PCoIP protocol.

During UAG configuration, you specify the address of the internal Connection Servers. The address you enter should be a DNS name that resolves to an internal load balancing VIP for the Connection Servers.

If you have split DNS, you can use the same DNS name for both external UAG access, and for internal Connection Server load balancing. Externally, configure the DNS name to resolve to the UAG Load Balancing VIP. Internally, configure the DNS name to resolve to the internal VIP that load balances the Connection Servers.

For Cloud Pod Architecture, configure separate VIPs in each datacenter. Then configure NetScaler Citrix ADC GSLB to resolve a single DNS name to multiple VIPs.

Protocols/Ports

To support Blast Extreme, PCoIP, and HTML Blast connectivity, the following ports must be load balanced to the UAGs:

  • TCP 443
  • UDP 443
  • TCP 4172
  • UDP 4172
  • TCP 8443
  • UDP 8443

The initial connection to UAG is always TCP 443 (HTTPS). If a user is load balanced on port 443 to a particular UAG, then the connection on UDP 4172 must go the same UAG. Normally load balancing persistence only applies to a single port number, so whatever UAG was selected for port 443, won’t be considered for the 4172 connection. But in NetScaler Citrix ADC, you can configure a Persistency Group to use a single persistency across multiple load balancing Virtual Servers with different port numbers. In F5, you configure Match Across Services, as detailed by Aresh Sarkari at Persistence Profile – F5 LTM Load Balancing for VMware Unified Access Gateway Appliance.

This topic primarily focuses on NetScaler Citrix ADC GUI configuration. Alternatively, you can skip directly to the CLI commands.

Load Balancing Monitors

Users connect to Unified Access Gateway appliances on multiple ports: TCP 443, UDP 443, TCP 8443, UDP 8443, TCP 4172, and UDP 4172. Create Load Balancing Monitors for each port number. Since UDP can’t be easily monitored, use TCP monitors as substitutes for UDP. That means you only need four monitors:

  • TCP 443 – HTTPS
    • HEAD /favicon.ico or GET /favicon.ico. This string can detect if UAG is in Quiesce mode, or if Connection Server is disabled in Horizon Console. See VMware 56636 for supported monitoring strings.
  • TCP 4172
  • TCP 8443

The procedure for configuring monitors changed in NetScaler 12.0 build 56 and newer.

SSL (443) Monitor for Connection Server Health

  1. On the left, expand Traffic Management, expand Load Balancing, and click Monitors.
  2. On the right, click Add.
  3. Name it Horizon-SSL or similar.
  4. In the Type field, click where it says Click to select.
  5. In the Monitor Types list, click the circle next to HTTP.
  6. Scroll up and click the blue Select button.
  7. To reduce UAG CPU, VMware recommends setting the Interval to 30 seconds.
  8. In the HTTP Request field, enter GET /favicon.ico. See VMware 56636 for supported health monitoring requests.
  9. Check the box next to Secure.
  10. Scroll down and click Advanced Parameters to expand it.
  11. In the Advanced Parameters section, in the Destination Port field, enter 443.
  12. Scroll down to the TROFS Code field and enter 503. When UAG is in Quiesce mode, TROFS will cause the service to transition to out of service allowing existing connections instead of directly going down and killing existing sessions. (h/t Henry Heres)
  13. Scroll down, and click Create.

PCoIP (4172) Monitor

  1. On the left, expand Traffic Management, expand Load Balancing, and click Monitors.
  2. On the right, click Add.
  3. Name it Horizon-PCoIP or similar.
  4. For the Type field, click where it says Click to select and select TCP from the Monitor Types list.
  5. Scroll down to Advanced Parameters, click Advanced Parameters to expand it, and then enter 4172 in the Destination Port field. This forces the monitor to connect to port 4172 even if the monitor is bound to a service group that is configured for a different port number.
  6. Scroll down, and click Create.

Blast (8443) Monitor

  1. On the left, expand Traffic Management, expand Load Balancing, and click Monitors.
  2. On the right, click Add.
  3. Name it Horizon-Blast or similar.
  4. For the Type field, click where it says Click to select and select TCP from the Monitor Types list.
  5. Scroll down to Advanced Parameters, click Advanced Parameters to expand it, and then enter 8443 in the Destination Port field. This forces the monitor to connect to port 8443 even if the monitor is bound to a service group that is configured for a different port number.
  6. Scroll down, and click Create.

UAG DDoS

NetScaler Citrix ADC Monitors might trigger UAG’s DDoS protection. To stop this: (source = UAG breaks after a few days. They break 100% of the time. at VMware Discussions)

  1. Point your browser to the UAG appliance’s admin interface using https, port 9443 and path /admin.
  2. Login to the admin interface.
  3. On the right, under Configure Manually, click Select.
  4. In the Advanced Settings section, click the gear icon for System Configuration.
  5. Scroll down.
  6. Change Request Timeout to 0.
  7. Change Body Receive Timeout to 0.
  8. Click Save.

Load Balancing Servers

Create Load Balancing Server Objects for the DMZ Unified Access Gateway appliances.

  1. On the left, expand Traffic Management, expand Load Balancing, and click Servers.
  2. On the right, click Add.
  3. Enter a descriptive server name, usually it matches the actual appliance name.
  4. Enter the IP address of a Unified Access Gateway appliance.
  5. Enter comments to describe the server. Click Create.
  6. Continue adding Unified Access Gateway appliances.

Load Balancing Service Groups

Overview

Since there are six protocol/ports to UAG, there will be six service groups – one for each protocol/port:

  • TCP 443 – SSL_BRIDGE
  • UDP 443
  • UDP 4172
  • TCP 4172
  • TCP 8443 – SSL_BRIDGE
  • UDP 8443

Users will initially connect to TCP port 443, and then must be redirected to one of the other ports on the same UAG appliance that was initially used for the TCP 443 connection. If TCP 443 is up, but UDP 4172 is down on the same appliance, then you probably TCP 443 to go down too. To facilitate this, bind all three port number monitors to the TCP 443 service. If any of the bound monitors goes down, then TCP 443 is also taken down.

  • Only the TCP 443 service group needs to monitor all port numbers.
  • Other port number service groups only need to monitor that specific port number. For example, the TCP 8443 Service Group should monitor port TCP 8443.
  • Since UDP is difficult to monitor, the UDP Service Groups will monitor the equivalent TCP port. For example, the UDP 4172 Service Group will monitor TCP 4172. This isn’t the best option, but it’s better than ping.

TCP 443 Load Balancing Service Group

  1. On the left, expand Traffic Management, expand Load Balancing, and click Service Groups.
  2. On the right, click Add.
  3. Give the Service Group a descriptive name (e.g. svcgrp-Horizon-SSL).
  4. Change the Protocol to SSL_BRIDGE.
  5. Click OK to close the Basic Settings section.
  6. On the left, in the Service Group Members section, click where it says No Service Group Member.

    1. Change the selection to Server Based.
    2. In the Select Server field, click where it says Click to select.
    3. Select the Unified Access Gateway appliances you created earlier, and then at the top of the page click the blue Select button.
    4. In the Port field, enter 443, and click Create.
  7. Click OK to close the Service Group Members section.
  8. On the right, in the Advanced Settings column, click Monitors to move it to the left.
  9. On the left, at the bottom of the page, in the Monitors section, click where it says No Service Group to Monitor Binding.

    1. In the Select Monitor field, click where it says Click to select.
    2. Click the circle next to the Horizon-SSL monitor, and then at the top of the page click the blue Select button.
    3. Click Bind.
  10. For load balancing UAGs, this Service Group should monitor all port numbers so that if any of the port numbers are down then the entire server should no longer receive connections. If load balancing internal Connection Servers, then you don’t need to bind any more monitors since the PCoIP Gateway and Blast Gateway are usually disabled. To bind more monitors, on the left, click where it says 1 Service Group to Monitor Binding.

    1. Click Add Binding.
    2. In the Select Monitor field, click where it says Click to select.
    3. Click the circle next to the Horizon-PCoIP monitor, and then at the top of the page click the blue Select button.
    4. Then click Bind.
    5. Repeat these steps to bind the Horizon-Blast monitor. Unfortunately you can only bind one monitor at a time.
      • If any of these monitors goes down, then the UAG is taken offline.
    6. Click Close.
  11. To verify the monitors, on the left, higher up the page in the Service Group Members section, click the line that says # Service Group Members.

    1. Right-click one of the members, and click Monitor Details.
    2. The Last Response should indicate Success. If you bound multiple monitors to the Service, then the member will only be UP if all monitors succeed.

      • UAG has a Quiesce mode, which tells the load balancer to stop sending it connections. You can enable Quiesce mode in the UAG’s System Configuration menu.
      • Connection Servers can be disabled.
      • If Quiesce mode is enabled on the UAG, or if the Connection Server is disabled, then the member of the service group will show Going Out of Service. You can see this by right-clicking on the Server Group and clicking Manage Members.

    3. Click Close when done.
  12. Then click Done to finish creating the Service Group.

Other Ports Load Balancing Service Groups

Here are general instructions for the other Horizon UAG load balancing service groups.

  1. On the left, go to Traffic Management > Load Balancing > Service Groups.
  2. On the right, click Add.
  3. Name it svcgrp-Horizon-UDP443 or similar.
  4. Change the Protocol to UDP. Click OK to close the Basic Settings section.
  5. On the left, click where it says No Service Group Member.

    1. Change the selection to Server Based, and then click Click to select.
    2. Select your multiple Unified Access Gateway appliances, and then at the top of the page click the blue Select button.
    3. Enter 443 as the Port. Click Create.
  6. Click OK to close the Service Group Members section.
  7. On the right, in the Advanced Settings column, click Monitors to move it to the left.

    1. On the left, in the Monitors section, click where it says No Service Group to Monitor Binding.
    2. For the Select Monitor field, click where it says Click to select.
    3. Select the Horizon-SSL monitor, click Select, and then click Bind. Since we don’t have a UDP monitor, we’re binding the TCP monitor instead.
  8. Click Done to finish creating the Service Group for UDP 443.
  9. Add another Service Group for PCoIP on TCP 4172.
    1. Name = svcgrp-Horizon-PCoIPTCP or similar.
    2. Protocol = TCP
    3. Members = multiple Unified Access Gateway appliances.
    4. Port = 4172.
    5. Monitors = Horizon-PCoIP. You can add the other monitors if desired.
  10. Add another Service Group for PCoIP on UDP 4172.
    1. Name = svcgrp-Horizon-PCoIPUDP or similar.
    2. Protocol = UDP
    3. Members = multiple Unified Access Gateway appliances
    4. Port = 4172.
    5. Monitors = Horizon-PCoIP. You can add the other monitors if desired.
  11. Add another Service Group for SSL_BRIDGE 8443.
    1. Name = svcgrp-Horizon-TCP8443 or similar.
    2. Protocol = SSL_BRIDGE
    3. Members = multiple Unified Access Gateway appliances
    4. Port = 8443.
    5. Monitors = Horizon-Blast. You can add the other monitors if desired.
  12. Add another Service Group for UDP 8443 (Blast Extreme in Horizon 7).
    1. Name = svcgrp-Horizon-UDP8443 or similar.
    2. Protocol = UDP
    3. Members = multiple Unified Access Gateway appliances
    4. Port = 8443.
    5. Monitors = Horizon-Blast. You can add the other monitors if desired.
  13. The six service groups should look something like this:

Load Balancing Virtual Servers

Unified Access Gateway appliances listen on multiple ports so you will need separate load balancers for each port number. Here is a summary of their Virtual Servers, all listening on the same Virtual IP address:

  • Virtual Server on SSL_BRIDGE 443 – bind the SSL_BRIDGE 443 service group.
  • Virtual Server on UDP 443 (Horizon 7) – bind the UDP 443 service group.
  • Virtual Server on UDP 4172 – bind the PCoIP UDP service group.
  • Virtual Server on TCP 4172 – bind the PCoIP TCP service group.
  • Virtual Server on SSL_BRIDGE 8443 – bind the SSL_BRIDGE 8443 service group.
  • Virtual Server on UDP 8443 (Horizon 7) – bind the UDP 8443 service group.

Do the following to create the Virtual Servers:

  1. On the left, under Traffic Management > Load Balancing, click Virtual Servers.
  2. On the right, click Add.
  3. In the Basic Settings section:
    1. Name it lbvip-Horizon-SSL or similar.
    2. Change the Protocol to SSL_BRIDGE.
    3. Specify a new VIP. This one VIP will be used for all of the Virtual Servers.
    4. Enter 443 as the Port.
  4. Click OK to close the Basic Settings section.
  5. On the left, in the Services and Service Groups section, click where it says No Load Balancing Virtual Server ServiceGroup Binding.

    1. Click where it says Click to select.
    2. Click the circle next to the Horizon-SSL Service Group, and then at the top of the page click the blue Select button.
    3. Click Bind.
  6. Click Continue to close the Services and Service Groups section.
  7. Then click Done to finish creating the Load Balancing Virtual Server. Persistence will be configured later.
  8. Create another Load Balancing Virtual Server for UDP 443. You can right-click the existing Load Balancing Virtual Server and click Add to copy some settings.

    1. Name = lbvip-Horizon-UDP443
    2. Same VIP as the TCP 443 Load Balancer.
    3. Protocol = UDP, Port = 443
    4. Service Group Binding = the UDP 443 Service Group

  9. Create another Load Balancing Virtual Server for PCoIP UDP 4172:
    1. Name = lbvip-Horizon-PCoIPUDP
    2. Same VIP as the 443 Load Balancer.
    3. Protocol = UDP, Port = 4172
    4. Service Group Binding = the PCoIP UDP Service Group.

  10. Create another Load Balancing Virtual Server for PCoIP TCP 4172:
    1. Name = lbvip-Horizon-PCoIPTCP
    2. Same VIP as the 443 Load Balancer.
    3. Protocol = TCP, Port = 4172
    4. Service Group Binding = the PCoIP TCP Service Group

  11. Create another Load Balancing Virtual Server for SSL_BRIDGE 8443:
    1. Name = lbvip-Horizon-8443SSL
    2. Same VIP as the 443 Load Balancer.
    3. Protocol = SSL_BRIDGE, Port = 8443
    4. Service Group Binding = the TCP 8443 SSL_BRIDGE Service Group

  12. Create another Load Balancing Virtual Server for UDP 8443:
    1. Name = lbvip-Horizon-8443UDP
    2. Same VIP as the 443 Load Balancer.
    3. Protocol = UDP, Port = 8443
    4. Service Group Binding = the UDP 8443 Service Group

  13. This gives you six Load Balancing Virtual Servers on the same VIP, but different protocols and port numbers.

Persistency Group

Users will first connect to SSL_BRIDGE 443 and be load balanced. Subsequent connections to the other port numbers must go to the same load balanced appliance. Create a Persistency Group to facilitate this.

  1. On the left, under Traffic Management, expand Load Balancing, and click Persistency Groups.
  2. On the right, click Add.
  3. Give the Persistency Group a name (e.g. Horizon).
  4. Change the Persistence drop-down to SOURCEIP.
  5. Enter a Time-out that is equal to, or greater than the timeout in Horizon View Administrator, which defaults to 10 hours (600 minutes).
  6. In the Virtual Server Name section, click Add.
  7. Move all six Horizon Load Balancing Virtual Servers to the right. Click Create.

Horizon Connection Server Locked.properties File

Horizon Connection Server’s default security settings might prevent you from connecting to load balanced Connection Servers and/or Unified Access Gateways. On the Connection Servers, go to C:\Program Files\VMware\VMware View\Server\sslgateway\conf, edit or create locked.properties file, and enter the following:

allowUnexpectedHost=true
checkOrigin=false
enableCORS=false

More details at VMware 2144768 Accessing the Horizon View Administrator page displays a blank error window in Horizon and 85801 Cross-Origin Resource Sharing (CORS) with Horizon 8 and loadbalanced HTML5 access. allowUnexpectedHost defaults to false in Horizon 2306 and Horizon 2212.1 and newer. Another option is to add portalHost entries as detailed at Allow HTML Access Through a Gateway at VMware Docs.

Load Balancing CLI Commands

Internal Connection Server Load Balancing

add server VCS01 10.2.2.19
add server VCS02 10.2.2.20
add serviceGroup svcgrp-VCS-SSL SSL_BRIDGE
add lb vserver lbvip-Horizon-SSL SSL_BRIDGE 10.2.5.203 443 -persistenceType SOURCEIP -timeout 600
bind lb vserver lbvip-Horizon-SSL svcgrp-VCS-SSL
add lb monitor Horizon-SSL HTTP -respCode 200 -httpRequest "GET /favicon.ico" -destPort 443 -secure YES
bind serviceGroup svcgrp-VCS-SSL VCS01 443
bind serviceGroup svcgrp-VCS-SSL VCS02 443
bind serviceGroup svcgrp-VCS-SSL -monitorName Horizon-SSL

Unified Access Gateway load balancing with Blast and PCoIP

add server UAG01 10.2.2.187
add server UAG02 10.2.2.188
add serviceGroup svcgrp-Horizon-SSL SSL_BRIDGE
add serviceGroup svcgrp-Horizon-UDP443 UDP
add serviceGroup svcgrp-Horizon-PCoIPTCP TCP
add serviceGroup svcgrp-Horizon-PCoIPUDP UDP
add serviceGroup svcgrp-Horizon-TCP8443 SSL_BRIDGE
add serviceGroup svcgrp-Horizon-UDP8443 UDP
add lb vserver lbvip-Horizon-SSL SSL_BRIDGE 10.2.5.204 443
add lb vserver lbvip-Horizon-UDP443 UDP 10.2.5.204 443
add lb vserver lbvip-Horizon-PCoIPUDP UDP 10.2.5.204 4172
add lb vserver lbvip-Horizon-PCoIPTCP TCP 10.2.5.204 4172
add lb vserver lbvip-Horizon-8443SSL SSL_BRIDGE 10.2.5.204 8443
add lb vserver lbvip-Horizon-8443UDP UDP 10.2.5.204 8443
bind lb vserver lbvip-Horizon-SSL svcgrp-Horizon-SSL
bind lb vserver lbvip-Horizon-UDP443 svcgrp-Horizon-UDP443
bind lb vserver lbvip-Horizon-PCoIPTCP svcgrp-Horizon-PCoIPTCP
bind lb vserver lbvip-Horizon-PCoIPUDP svcgrp-Horizon-PCoIPUDP
bind lb vserver lbvip-Horizon-8443SSL svcgrp-Horizon-TCP8443
bind lb vserver lbvip-Horizon-8443UDP svcgrp-Horizon-UDP8443
add lb group Horizon -persistenceType SOURCEIP -timeout 600
bind lb group Horizon lbvip-Horizon-SSL
bind lb group Horizon lbvip-Horizon-UDP443
bind lb group Horizon lbvip-Horizon-PCoIPUDP
bind lb group Horizon lbvip-Horizon-PCoIPTCP
bind lb group Horizon lbvip-Horizon-8443SSL
bind lb group Horizon lbvip-Horizon-8443UDP
set lb group Horizon -persistenceType SOURCEIP -timeout 600
add lb monitor Horizon-SSL HTTP -respCode 200 -httpRequest "GET /favicon.ico" -destPort 443 -secure YES -trofscode 503
add lb monitor Horizon-PCoIP TCP -LRTM DISABLED -destPort 4172 -secure YES
add lb monitor Horizon-Blast TCP -LRTM DISABLED -destPort 8443 -secure YES
bind serviceGroup svcgrp-Horizon-SSL UAG01 443
bind serviceGroup svcgrp-Horizon-SSL UAG02 443
bind serviceGroup svcgrp-Horizon-SSL -monitorName Horizon-SSL
bind serviceGroup svcgrp-Horizon-SSL -monitorName Horizon-PCoIP
bind serviceGroup svcgrp-Horizon-SSL -monitorName Horizon-Blast
bind serviceGroup svcgrp-Horizon-UDP443 UAG01 443
bind serviceGroup svcgrp-Horizon-UDP443 UAG02 443
bind serviceGroup svcgrp-Horizon-UDP443 -monitorName Horizon-SSL
bind serviceGroup svcgrp-Horizon-PCoIPTCP UAG01 4172
bind serviceGroup svcgrp-Horizon-PCoIPTCP UAG02 4172
bind serviceGroup svcgrp-Horizon-PCoIPTCP -monitorName Horizon-PCoIP
bind serviceGroup svcgrp-Horizon-PCoIPUDP UAG01 4172
bind serviceGroup svcgrp-Horizon-PCoIPUDP UAG02 4172
bind serviceGroup svcgrp-Horizon-PCoIPUDP -monitorName Horizon-PCoIP
bind serviceGroup svcgrp-Horizon-TCP8443 UAG01 8443
bind serviceGroup svcgrp-Horizon-TCP8443 UAG02 8443
bind serviceGroup svcgrp-Horizon-TCP8443 -monitorName Horizon-Blast
bind serviceGroup svcgrp-Horizon-UDP8443 UAG01 8443
bind serviceGroup svcgrp-Horizon-UDP8443 UAG02 8443
bind serviceGroup svcgrp-Horizon-UDP8443 -monitorName Horizon-Blast

Citrix Director Load Balancing – Citrix ADC

Last Modified: Mar 9, 2022 @ 4:21 pm

25 Comments

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Change Log

  • 2018 Dec 20 – updated screenshots for ADC 12.1 build 50.
  • 2017 Dec 25 – updated entire article for 12.0 build 56. Monitor section has new 12.0 build 56 instructions.

Monitor

12.0 build 56 and newer

Instructions for creating the monitor changed in 12.0 build 56 and newer. If your build is older, skip to the older instructions.

  1. On the left, expand Traffic Management, expand Load Balancing, and click Monitors.
  2. On the right, click Add.
  3. Name it Director or similar.
  4. In the Type field, click where it says Click to select.
  5. Scroll down and click the circle next to HTTP.
  6. At the top of the window, click the blue Select button.
  7. Scroll down the Basic  Parameters section, and check the box next to Secure. This checkbox instructs the monitor to connect to the Director Servers using https/SSL/TLS instead of http.
  8. In the HTTP Request box, enter GET /Director/LogOn.aspx?cc=true.
  9. If Single Sign-on (Windows Integrated Authentication) is enabled on Director, then you might have to add 302 as a Response Code.
  10. Scroll down, and click Create.
  11. Jump to the Servers section.

12.0 older than build 56

  1. On the left, expand Traffic Management, expand Load Balancing, and click Monitors.
  2. On the right, click Add.
  3. Name it Director or similar.
  4. Change the Type drop-down to HTTP.
  5. If you will use SSL to communicate with the Director servers, then on the Standard Parameters tab, scroll down, and check the box next to Secure.
  6. Scroll up, and switch to the Special Parameters tab.
  7. In the HTTP Request field, enter GET /Director/LogOn.aspx?cc=true
    1. If Single Sign-on is enabled on Director, then you might have to add 302 as a Response Code.
  8. Scroll down, and click Create.

Servers

  1. On the left, expand Traffic Management, expand Load Balancing, and click Servers.
  2. On the right, click Add.
  3. Enter a descriptive server name. Usually it matches the actual server name.
  4. Enter the IP address of the Director server.
  5. Enter comments to describe the server. Click Create.
  6. Continue adding Director servers.

Service Group

  1. On the left, expand Traffic Management, expand Load Balancing, and click Service Groups.
  2. On the right, click Add.
  3. Give the Service Group a descriptive name (e.g. svcgrp-Director-SSL).
  4. Change the Protocol to HTTP or SSL, depending on if IIS on the Director server is enabled for https or not.
    • If the protocol is SSL, ensure the Monitor for Director has Secure enabled, as detailed earlier.
  5. Scroll down, and click OK.

  6. On the left, in the Service Group Members section, click where it says No Service Group Member.

    1. Change the selection to Server Based, and then Click to select the Director server objects.

    2. Enter 80 or 443 as the port. Then click Create.
  7. Click OK to close the Service Group Members section.
  8. On the right, under Advanced Settings, click Monitors.
  9. On the left, in the Monitors section, click where it says No Service Group to Monitor Binding.

    1. Click where it says to Click to select.
    2. Click the circle next to the Director monitor you created earlier. The monitor might be on Page 2.
      • The circle must be clicked exactly (no room for error). If you click outside the circle, then the monitor will open for editing. If this happens, click Close to return to the selection screen.
    3. At the top of the window, click the blue Select button.
    4. Then click Bind.
  10. To verify that the monitor is working, on the left, in the Service Group Members section, click the Service Group Members line.
  11. Right-click a member, and click Monitor Details.
  12. The Last Response should be Success – HTTP response code 200 received. Click Close twice.
  13. Then click Done.

Responder

Create a Responder policy to redirect users from the root page to /Director.

  1. Go to AppExpert > Responder, and enable the feature if it isn’t already enabled.
  2. Go to AppExpert > Responder > Actions.
  3. On the right, click Add.

    1. Give the Action a name (e.g. Director_Redirect).
    2. Change the Type to Redirect.
    3. In the Expression box, enter "/Director", including the quotes.
  4. On the bottom, click Create.
  5. Go to AppExpert > Responder > Policies.
  6. On the right, click Add.

    1. Give the Policy a name (e.g. Director_Redirect).
    2. Select the previously created Action.
    3. In the Expression box, enter HTTP.REQ.URL.PATH.EQ("/")
  7. On the bottom, click Create.

Load Balancing Virtual Server

  1. Create or install a certificate that will be used by the SSL Virtual Server. This certificate must match the DNS name for the load balanced Director servers.
  2. On the left, under Traffic Management > Load Balancing, click Virtual Servers.
  3. On the right, click Add.
  4. Do the following in the Basic Settings section:
    1. Name it lbvip-Director-SSL or similar.
    2. Change the Protocol to SSL.
    3. Specify a new internal VIP.
    4. Enter 443 as the Port.
    5. Click OK to close the Basic Settings section.
  5. On the left, in the Services and Service section, click where it says No Load Balancing Virtual Server ServiceGroup Binding.

    1. Click where it says Click to select.
    2. Click the circle next to a previously created Service Group. It might be on page 2.
      • The circle must be clicked exactly (no room for error). If you click outside the circle, then the Service Group will open for editing. If this happens, click the x on the top right, or the Done button on the bottom, to return to the selection screen.
    3. At top of the screen, click the blue Select button.
    4. Click Bind.
  6. Click Continue to close the Services and Service Groups section.
  7. Click where it says No Server Certificate.

    1. Click where it says Click to select.
    2. Click the circle next to a certificate that matches the FQDN that resolves to this VIP. It might be on page 2.
    3. At the top of the window, click the blue Select button.
    4. Click Bind.
  8. Click Continue to close the Certificate section.
  9. On the right, in the Advanced Settings column, click Persistence.
  10. On the left, in the Persistence section, do the following:
    1. Change the Persistence drop-down to COOKIEINSERT. The Persistence section in 12.0 build 56 and newer is slightly different than older builds.
    2. Set the Time-out to 0 minutes. This makes it a session cookie instead of a persistent cookie.
    3. Set the Backup Persistence to SOURCEIP.
    4. Set the Backup Time-out to match the timeout of Director. The default timeout for Director is 245 minutes.
    5. The IPv4 Netmask should default to 32 bits.
    6. Click OK to close the Persistence section.
  11. On the right, in the Advanced Settings section, add the Policies section.
  12. On the left, in the Policies section, click the plus icon.

    1. Change the Choose Policy drop-down to Responder, and click Continue.
    2. Click to select the previously created Director_Redirect policy.

      • The circle next to the Responder policy must be clicked exactly (no room for error). If you click outside the circle, then the policy will open for editing. If this happens, click Close to return to the selection screen.
    3. After selecting, click Bind.
  13. If you haven’t enabled the Default SSL Profile, then perform other normal SSL configuration including: disable SSLv3, bind a Modern A+ Cipher Group, and enable Strict Transport Security.

SSL Redirect

Do one of the following to configure a redirect from HTTP to HTTPS:

SSL Warning

  1. If you are doing SSL Offload (SSL on front end, HTTP on back end), when connecting to Director, it might complain about “You are not using a secure connection”.
  2. To turn off this warning, login to the Director servers, and run IIS Manager.
  3. On the left, navigate to Server > Sites > Default Web Site > Director.
  4. In the middle, double-click Application Settings.
  5. Change UI.EnableSslCheck to false.

CLI Commands

Here is a list of NetScaler CLI commands for Director Load Balancing:

# SSL Global Parameters
set ssl parameter -denySSLReneg NONSECURE

# Certs
add ssl certKey WildcardCorpLocal -cert WildcardCorpLocal.pfx -key WildcardCorpLocal.pfx -inform PFX -passcrypt "Passw0rd"

# SSL Cipher Group
add ssl cipher custom-ssllabs-cipher
bind ssl cipher custom-ssllabs-cipher -cipherName TLS1.2-ECDHE-RSA-AES256-GCM-SHA384 -cipherPriority 1
bind ssl cipher custom-ssllabs-cipher -cipherName TLS1.2-ECDHE-RSA-AES128-GCM-SHA256 -cipherPriority 2
bind ssl cipher custom-ssllabs-cipher -cipherName TLS1.2-ECDHE-RSA-AES-256-SHA384 -cipherPriority 3
bind ssl cipher custom-ssllabs-cipher -cipherName TLS1.2-ECDHE-RSA-AES-128-SHA256 -cipherPriority 4
bind ssl cipher custom-ssllabs-cipher -cipherName TLS1-ECDHE-RSA-AES256-SHA -cipherPriority 5
bind ssl cipher custom-ssllabs-cipher -cipherName TLS1-ECDHE-RSA-AES128-SHA -cipherPriority 6
bind ssl cipher custom-ssllabs-cipher -cipherName TLS1.2-DHE-RSA-AES256-GCM-SHA384 -cipherPriority 7
bind ssl cipher custom-ssllabs-cipher -cipherName TLS1.2-DHE-RSA-AES128-GCM-SHA256 -cipherPriority 8
bind ssl cipher custom-ssllabs-cipher -cipherName TLS1-DHE-RSA-AES-256-CBC-SHA -cipherPriority 9
bind ssl cipher custom-ssllabs-cipher -cipherName TLS1-DHE-RSA-AES-128-CBC-SHA -cipherPriority 10
bind ssl cipher custom-ssllabs-cipher -cipherName TLS1-AES-256-CBC-SHA -cipherPriority 11
bind ssl cipher custom-ssllabs-cipher -cipherName TLS1-AES-128-CBC-SHA -cipherPriority 12

# Responder Actions
add responder action Director_Redirect redirect "\"/Director\"" -responseStatusCode 302

# Responder Policies
add responder policy Director_Redirect "HTTP.REQ.URL.PATH.EQ(\"/\")" Director_Redirect

# Load Balancing Global Parameters
enable ns mode FR L3 Edge USNIP PMTUD ULFD
set ns param -cookieversion 1
set ns tcpParam -WS ENABLED -SACK ENABLED
set ns httpParam -dropInvalReqs ON

# Monitors
add lb monitor Director HTTP -respCode 200 302 -httpRequest "GET /Director/LogOn.aspx?cc=true" -LRTM DISABLED -secure YES

# Servers
add server Director01 xdc01.corp.local
add server Director02 xdc02.corp.local

# Service Groups
add serviceGroup svcgrp-Director-SSL SSL -maxClient 0 -maxReq 0 -cip DISABLED -usip NO -useproxyport YES -cltTimeout 180 -svrTimeout 360 -CKA NO -TCPB NO -CMP YES
bind serviceGroup svcgrp-Director-SSL Director01 443
bind serviceGroup svcgrp-Director-SSL Director02 443
bind serviceGroup svcgrp-Director-SSL -monitorName Director

# Load Balancing Virtual Servers
add lb vserver lbvip-Director-SSL SSL 10.2.5.210 443 -persistenceType COOKIEINSERT -timeout 0 -persistenceBackup SOURCEIP -backupPersistenceTimeout 245 -cltTimeout 180 -redirectFromPort 80 -httpsRedirectUrl "https://director.corp.com"
bind lb vserver lbvip-Director-SSL svcgrp-Director-SSL
bind lb vserver lbvip-Director-SSL -policyName Director_Redirect -priority 100 -gotoPriorityExpression END -type REQUEST

# SSL Virtual Servers
set ssl vserver lbvip-Director-SSL -ssl3 DISABLED -HSTS ENABLED -maxage 157680000
unbind ssl vserver lbvip-Director-SSL -cipherName ALL
bind ssl vserver lbvip-Director-SSL -cipherName custom-ssllabs-cipher
bind ssl vserver lbvip-Director-SSL -certkeyName WildcardCorpLocal
bind ssl vserver lbvip-Director-SSL -eccCurveName P_256
bind ssl vserver lbvip-Director-SSL -eccCurveName P_384
bind ssl vserver lbvip-Director-SSL -eccCurveName P_224
bind ssl vserver lbvip-Director-SSL -eccCurveName P_521

SSL VPN – Citrix Gateway

Last Modified: May 5, 2021 @ 7:53 am

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Overview

Here’s an overview of the Citrix Gateway connection process:

  1. Users use SSL/TLS to connect to a Citrix Gateway Virtual Server (VIP).
  2. Citrix Gateway prompts the user for authentication.
  3. Once the user is authenticated, Citrix Gateway uses Session Policies/Profiles to determine what happens next.

Citrix Gateway supports six different connection methods:

  • ICA Proxy to Citrix Virtual Apps and Desktops (CVAD) (aka XenApp/XenDesktop) and StoreFront – the client is built into Citrix Workspace app (aka Citrix Receiver)
  • SSL VPN – requires installation of Citrix Gateway plug-in (VPN client)
  • Clientless – browser only, no VPN client, uses rewrite
  • Secure Browse – from MDX-wrapped mobile applications (Citrix Endpoint Management aka XenMobile), uses rewrite
  • RDP Proxy – only RDP client is needed
  • PCoIP Proxy – only VMware Horizon Client is needed

You can configure Citrix Gateway Session Policies/Profiles to only use one of the connection methods. Or Citrix Gateway can be configured to let users choose between ICA Proxy, Clientless, and SSL VPN connection methods. Here’s a sample Client Choices screen using the RfWebUI theme:

  • The Clientless Access option opens a portal page that has icons from Citrix StoreFront (ICA Proxy), icons for RDP Proxy, icons for PCoIP Proxy, and links to websites.
    • The website links can be proxied through Citrix Gateway. Proxy methods include: clientless rewrite, SSL VPN, and traditional load balancing.
    • Citrix Gateway can optionally Single Sign-on to the websites.
  •  The Virtual App and Desktop Access option only displays icons from Citrix StoreFront (ICA Proxy). For other types of icons, you’ll need Clientless Access.
  • The Connect with Citrix Gateway Plug-in option launches the VPN tunnel. After the tunnel is established, a portal page is displayed. This can be the Clientless Access portal, or a user defined website URL (e.g. intranet).

Session Policies/Profiles have several settings that control the behavior seen after authentication:

  • ICA Proxy – ON or OFF
    • If ON, then ICA Proxy is the only connection method allowed, overriding the other connection methods.
    • ICA Proxy does not launch the VPN client. It only needs Citrix Workspace app.
    • ICA Proxy shows the Webpage that’s configured in the Web Interface Address field of the Session Profile. This is typically the StoreFront Receiver for Web page, but technically it can be any internal website.
    • If OFF, that doesn’t mean ICA Proxy doesn’t work. You can still send ICA traffic to the Citrix Gateway Virtual Server, and the Citrix Gateway Virtual Server will still proxy it to internal VDAs.
    • Setting it to OFF allows the other connection methods to function. For example, Clientless Access can show both Citrix Gateway Bookmarks and StoreFront published apps. If VPN is launched, then the portal page shown to the user after the tunnel is established can contain the StoreFront published applications.
  • Clientless Access – On, Off, Disabled
    • If On, then Clientless is the only connection method allowed, assuming ICA Proxy is not set to ON. After the user logs in, the user is presented with a portal page that contains a list of Gateway bookmarks and/or StoreFront published icons. The VPN Client is not launched.
    • The Home Page setting in the Session Profile allows you to display an internal website instead of displaying the Citrix Gateway Portal Page.
    • Bookmarks are configured at Citrix Gateway > Resources > Bookmarks. You can bind the Bookmarks (Urls) to the Citrix Gateway Virtual Server, or to AAA Groups.
    • Only Bookmarks configured for Clientless Access will work without a VPN. The internal websites are rewritten so they are proxied through Citrix Gateway. For example, if the internal website is http://intranet.corp.local, then Gateway rewrites them to https://gateway.corp.com/cvpn/http/internal.corp.local. This causes the web browser to send the HTTP Request to Citrix Gateway, which then forwards the HTTP Request to the internal web server. No VPN needed.
  • Plug-in Type – Windows/MAC OS X
    • If both Clientless and ICA Proxy are set to Off, then the VPN Client will be downloaded and launched.
    • Once the VPN tunnel is established, the webpage configured in the Home Page setting is displayed. Or the Citrix Gateway Portal Page (Clientless Access) is displayed if no Home Page is configured. The Bookmarks in the Portal Page can link to internal websites that are only accessible through a VPN tunnel. Or Bookmarks can be configured for Clientless Access.
    • Additional Gateway objects control VPN behavior including: DNS Suffix, Intranet Applications, Intranet IPs, and Authorization Policies.
  • Client Choices – checked or unchecked
    • If Client Choices is checked, then it displays a page containing up to three buttons allowing the user to choose between VPN, Clientless, or StoreFront. The Network Access with the Citrix Gateway Plug-in (VPN) button is always displayed. The Clientless Access button is displayed if Clientless Access is set to On or Off (not Disabled). The Virtual App and Desktop Access button is displayed if a Web Interface Address is configured.

Here are some characteristics of Session Policies:

  • Citrix Gateway > Global Settings > Change Global Settings has the same settings as a Session Profile. However, all Session Policies/Profiles override the settings configured in Global Settings. That’s the whole point of the Override Global checkboxes in the Session Profiles.
  • Session Policy Expression – If the Session Policy Expression is true, then the settings contained in the Session Profile are applied.
    • Action = Session Profile – The Session Profile is also sometimes called the Action. That’s because all Citrix ADC policies follow a standard structure – if the expression evaluates to True, then perform the Action. For Session Policies in particular, the policy Action = Session Profile.
    • EPA – The Session Policy Expression in Classic Syntax could include an Endpoint Analysis (EPA) expression.
  • Default Syntax Expressions vs Classic Syntax Policy Expressions – Citrix ADC 12 and newer supports Default (Advanced) Syntax Expressions on Session Policies, in addition to the older Classic Syntax.
    • No syntax mixing – All Session Policies bound anywhere must be either Default or Classic. You cannot mix the two types.
    • EPA is Classic only – EPA Scans are only supported in Classic Expressions.
    • AD Group in Default Syntax – Default Syntax allows expressions for AD Group Membership like HTTP.REQ.USER.IS_MEMBER_OF("MyADGroup"). This could eliminate AAA Groups in some circumstances.
  • Policy Bind Points – Session Policies can be bound to three different bind points – Citrix Gateway Virtual Server, AAA Groups, and AAA User.
    • When bound to a Citrix Gateway Virtual Server, the Session policy/profile applies to all users that log into that Virtual Server.
    • When bound to a AAA Group, the Session policy/profile only applies to members of the AAA group (Active Directory group or local group)
    • When bound to a AAA User, the Session policy/profile only applies to the AAA user (Active Directory user or local user)
  • Profile Conflicts – Multiple Session Policies/Profiles could apply to a single session. In this case, the Profile settings are merged. But if there’s a conflict (e.g. one Session Profile enables Clientless access, but another Session Profile disables Clientless access), then which one wins?
    • Priority number – When you bind a Session Policy to a bind point, you specify a priority number. This priority number usually defaults to 100.
    • Lowest priority number wins – The Session Policy binding that has the lowest priority number, wins. Session Policies bound with a priority of 80 will win over Session Policies bound with a priority of 100. Remember, for settings that don’t conflict, the two Profiles merge, but for settings that do conflict, the lower priority number policy/profile settings win.
    • Classic Policy Priority and multiple bind points – for Classic Session Policies the bind point location doesn’t matter. If you bind a Session Policy to a AAA Group with a priority of 100, and you also bind a Session Policy to the Citrix Gateway Virtual Server with a priority of 80, then the conflicting settings in the Session Policy bound to the Citrix Gateway Virtual Server will win because it has the lower priority number. You might think that AAA-bound policies always override Virtual Server-bound policies, but that is not the case.
    • Advanced Policy Priority and multiple AAA Groups – see CTX289931 AAA group session policies are not applying based on priority. The first created AAA Group overrides AAA Groups created later unless you specify the weight parameter when creating the AAA Group from the CLI.
  • Global Settings vs Virtual Server Settings – When you bind a Session Policy to a Citrix Gateway Virtual Server, the settings in the Session Profile only apply to connections through that particular Citrix Gateway Virtual Server.
    • Settings in Citrix Gateway > Global Settings > Change Global Settings apply to every Gateway Virtual Server.
    • Settings in AAA Group > Policies > Session Policy/Profile apply to every Gateway Virtual Server.
    • If you want a particular Gateway Virtual Server to override AAA or Global, your only choice is to bind a Session Policy to the Gateway Virtual Server with a lower priority number than the AAA Bind Points.

AAA Groups are a critical component of Citrix Gateway VPN configuration:

  • Group extraction – Make sure the LDAP Policy/Server is configured to extract to the user’s Active Directory Groups.
  • Create AAA Groups on the Citrix ADC that match exactly (case sensitive) with the user’s Active Directory Group Name.
    • Default Syntax and AD Groups – An alternative to AAA Groups is to use HTTP.REQ.USER.IS_MEMBER_OF("MyADGroup") Default Syntax expressions. However, Default Syntax does not support Endpoint Analysis. And Default Syntax only applies to Session Policies and Authorization Policies, so you might still need AAA Groups for Bookmarks, Intranet Applications, and Intranet IPs.
  • You can bind policies and other Gateway objects to the AAA Group, and these bindings only affect that particular AAA Group. These bindings include:
  • If the user belongs to multiple AAA Groups, then policies are applied as follows:
    • Session Policies – the settings are merged, unless there’s a conflict. If a conflict, then the policy with the lowest priority number wins.
    • Bookmarks, Intranet Applications, and Authorization Policies are merged.
    • Intranet IPs (IP Pool) are probably random allocation. It’s probably best to make sure a user only belongs to one AAA Group that assigns Intranet IPs.
  • You can also create local AAA Groups that are unrelated to Active Directory groups. There are several ways of getting users into these local AAA groups:
    • Create local AAA Users and assign them to the AAA Group
    • Configure Session Policy/Profile with a Client Security Check String (EPA Scan). If the scan succeeds, users are placed into local Authorization AAA Groups. If the scan fails, then users are placed into a local Quarantine AAA Group, and removed from all other AAA Groups.
    • When users are authenticated with a particular authentication server, the authentication server can be configured to place users into a Default Authentication Group. This lets you apply different Session Policy/Profiles (and other Gateway objects) depending on how the user authenticated.

Citrix Gateway supports Client Security Expressions (Endpoint Analysis expressions) at four different locations:

  • nFactor (Authentication Virtual Server) Advanced EPA Policy and EPA Action – this is the preferred method in ADC 13 and newer since Classic EPA is supposed to be removed in ADC 13.1 and newer. See nFactor EPA for details.
  • Classic Preauthentication Policy Expression
    • If the EPA Scan succeeds, then the user is allowed to login.
    • If the EPA Scan fails, then the user is not allowed to login.
    • Preauthentication Policies are bound to Citrix Gateway Virtual Servers only, and thus applies to all users of that Virtual Server.
  • Classic Session Policy Expression – Note: Advanced Session Policies do not support EPA expressions. Use nFactor instead.
    • This type of EPA Scan is configured in the Session Policy Expression, not the Session Profile.
    • If the EPA Scan succeeds, then the settings in the Session Profile are applied to the session.
    • If the EPA Scan fails, then the Session Profile is ignored. Other Session Policies expressions are still evaluated. Remember, Session Policy/Profiles merge, so all applicable Session Policies must be considered.
    • A limitation of this EPA method is that nothing negative happens. Instead, you typically design higher priority number (lower priority) Session Policies with restrictive settings so that if the EPA Scans fail, then users still get something. For example, you can configure your highest priority number Session Policy/Profile with StoreFront (ICA Proxy) only. In the lower priority number Session Policies/Profiles, VPN might be enabled, but only if the EPA scan succeeds. More restrictive Session Profiles usually uncheck Client Choices, and enable Clientless Access or ICA Proxy.
    • This method of EPA Scans is used in SmartAccess and SmartControl configurations.
    • EPA expressions are not supported in Default Syntax, so you’ll need to use Classic Syntax instead.
  • Session Profile > Security tab > Advanced Settings > Client Security Check String
    • If the EPA Scan succeeds, add the user to the listed Authorization AAA Groups.
    • If the EPA Scan fails, add the user to the selected Quarantine Group, and remove the user from all other AAA Groups.
    • If Quarantine Group is not defined, then prevent SSL VPN. Other methods of connecting (Clientless, StoreFront), still work.
  • Assigning EPA scans to Session Policies and Session Profiles is also known as Post-Authentication EPA Scans.
  • If Endpoint Analysis is configured anywhere, then an Endpoint Analysis plug-in is downloaded to the Windows or Mac client.

Prerequisites

Gateway Universal Licenses

Except for ICA Proxy, all Citrix Gateway connection methods require a Citrix Gateway Universal License for each concurrent session. Go to System > Licenses.

On the right, make sure Maximum Citrix Gateway User licenses are installed. Most Citrix ADC Editions come with built-in licenses. For example, Citrix ADC Premium Edition comes with Unlimited Gateway licenses.

DNS Name Servers

DNS usually needs to function across the VPN tunnel. Go to Traffic Management > DNS > Name Servers to add DNS servers.

In ADC 13.0 build 71.44 and newer, VPN plug-in for Windows supports Secure DNS update. This feature is disabled by default. To enable it, create the following on the client device: (source = 13.0-71.44 release notes) 💡

  • HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\Secure Access Client\secureDNSUpdate value of type REG_DWORD and set it to 1.
    • When you set the value to 1, the VPN plug-in tries the unsecure DNS update first. If the unsecure DNS update fails, the VPN plug-in tries the secure DNS update.
    • To try only the secure DNS update, you can set the value to 2.

AAA Groups

  1. Edit your LDAP Policy/Server, and make sure Group Extraction is configured. Configure the Group Attribute and the Sub Attribute Name. This causes Citrix ADC to extract the user’s AD groups when the user logs in using LDAP.
  2. Go to Citrix Gateway > User Administration > AAA Groups.
  3. On the right, click Add.
  4. Enter a case sensitive group name that matches the group name in Active Directory. Click OK.
  5. On the right, in the Advanced Settings column, you can see the types of objects that can be bound to AAA Groups. These objects are detailed later in this post.

Create Session Profile

To enable SSL VPN: first create the Session Profile. Then create a Session Policy.

You can create multiple Session Policies/Profiles with different settings. Then you can bind these Session Policies to AAA groups and/or Citrix Gateway Virtual Servers. The Session Profiles are merged, and if conflicts, lower priority bind points win.

To enable SSL VPN in a Session Profile:

  1. On the left, expand Citrix Gateway, expand Policies, and click Session.
  2. On the right, switch to the Session Profiles tab, and click Add.
  3. Name the profile VPN or similar.
  4. In Session Profiles, every field has an Override Global checkbox to the right of it. If you check this box next to a particular field, then you can configure that field, and the field in this session profile will override settings configured globally (Citrix Gateway > Global Settings > Change Global Settings), or in a lower priority (higher priority number) session policy.

Network Configuration tab

  1. In the Session Profile, switch to the Network Configuration tab.
  2. You will find a setting that lets you select a DNS Virtual Server. Or if you don’t select anything, then the tunnel will use the DNS servers configured under Traffic Management > DNS > Name Servers.

Client Experience Tab

  1. In the Session Profile, switch to the Client Experience tab. This tab contains most of the Citrix Gateway VPN settings.
  2. Override Plug-in Type, and set it to Windows/Mac OS X.
  3. On the Client Experience tab, override Split Tunnel and make your choice. Setting it to OFF will force all traffic to use the tunnel. Setting it to ON will require you to create Intranet Applications so the Citrix Gateway Plug-in will know which traffic goes through the tunnel, and which traffic goes directly out the client NIC (e.g. to the Internet). REVERSE means all traffic goes through the tunnel except for the addresses defined in Intranet Applications.
  4. On the Client Experience tab, there are timers that can be configured. Global Settings contains default timers, so you might want to configure this Session Profile to override the defaults and increase the timeouts. See Configuring Time-Out Settings at Citrix Docs for details.
    1. Client Idle Time-out is a Citrix Gateway Plug-in timer that disconnects the session if there is no user activity (mouse, keyboard) on the client machine.
    2. Session Time-out is a Citrix Gateway timer that disconnects the session if there is no network activity for this duration.
    3. In addition to these two timers, on the Network Configuration tab, under Advanced Settings…
    4. There’s a Forced Timeout setting.
  5. By default, once the VPN tunnel is established, a portal page appears containing Gateway Bookmarks, and StoreFront published icons. An example of the portal page in the RfWebUI theme is shown below:

    1. The X1 theme is shown below:
  6. On the Client Experience tab, the Home Page field lets you override the the default portal page, and instead display a different webpage (e.g. Intranet). This homepage is displayed after the VPN tunnel is established (or immediately if connecting using Clientless Access).
  7. Citrix Gateway can automatically start the VPN tunnel whenever the user is remote. This method only starts the VPN Tunnel after the user is logged into Windows.
    1. On the Client Experience tab, click the plus icon next to AlwaysON Profile Name.
    2. Give the profile name. Hover over the question marks to see what each of them does.
    3. Then click Create.
    4. More info at AlwaysON at Citrix Docs.
  8. Citrix Gateway 12.1 build 51 and newer also support the VPN Client establishing a tunnel before the user logs into Windows. The pre-logon AlwaysOn Service feature requires certificate-based authentication and registry keys on the client device. See AlwaysOn service for Windows at Citrix Docs. 💡
  9. Additional VPN settings can be found by clicking Advanced Settings near the bottom of the Client Experience tab.
  10. Under Client Experience > Advanced Settings, on the General tab, there are settings to run a login script at login, enable/disable Split DNS, and enable Local LAN Access. Use the question marks to see what they do.
  11. Note: if Split Tunnel is OFF, and if Split DNS is set to REMOTE, Citrix Gateway only returns one IP address to DNS queries. This behavior can be changed by following Citrix CTX200243 DNS Query Responds with Only One IP to Client PC When Connected Through NetScaler Gateway Full VPN.
  12. Under Client Experience > Advanced Settings, on the General tab, is a checkbox for Client Choices. This lets the user decide if they want VPN, Clientless, or ICA Proxy (StoreFront). Without Client Choices, one of the connection methods will occur automatically, depending on what’s enabled.
  13. An example of Client Choices is shown below:

    • On the main Client Experience tab, if you enabled Client Choices, you can set Clientless Access to Off to add Clientless to the list of available connection methods in the Client Choices screen.
    • Clientless Access is difficult to remove from the Client Choices page since you need Clientless Access for StoreFront integration. The following removal instructions were confirmed on a custom Portal Theme based on RfWebUI:
      1. WinSCP to the Citrix ADC.
      2. Navigate to /var/netscaler/logon/themes/<yourThemeName>/css.
      3. Edit the file theme.css.
      4. At the bottom of the file, add the following code: (source = CTP Sam Jacobs at NetScaler Gateway Client Choices – hide/remove Virtual Apps and Desktops at Citrix Discussions. 
        div.box:nth-child(2) {
 display:none;
}
      5. When you refresh the Client Choices page, the Clientless box should be hidden.
  14. The Client Experience > Advanced Settings section has additional tabs. A commonly configured tab is Proxy, which allows you to enable a proxy server for VPN users.

Security Tab

  1. Back in the main Session Profile, switch to the Security tab.
  2. Set the default authorization to Allow or Deny. If Deny (recommended), you will need to create authorization policies to allow traffic across the tunnel. You can later create different authorization policies for different groups of users.

Published Applications Tab

  1. On the Published Applications tab, set ICA Proxy to Off. This ensures VPN is used instead of ICA Proxy.
  2. Configure the Web Interface Address to embed StoreFront into the default Clientless Access portal page.
    • Note: for X1 theme, additional iFrame configuration is required on the StoreFront side as detailed below. RfWebUI theme does not need any StoreFront changes.
    • From Michael Krasnove: if you configured the Session Policy to direct users to StoreFront, but aren’t using RfWebUI, then placing the following code in c:\inetpub\wwwroot\Citrix\StoreWeb\custom\script.js will cause StoreFront to end the VPN tunnel when the user logs off of StoreFront. 
      var LOGOFF_REDIRECT_URL = 'https://YourGatewayFQDN.com/cgi/logout';
 
// Prevent the default "logoff" screen from being displayed
CTXS.Controllers.LogoffController.prototype._handleLogoffResult = $.noop;
 
CTXS.Extensions.afterWebLogoffComplete = function () {
 window.location.href = LOGOFF_REDIRECT_URL;
};
  3. See the ICA Proxy post for more information on integrating StoreFront with Citrix Gateway.

Other Tabs

  1. The Remote Desktop tab is detailed in the RDP Proxy post.
  2. The PCoIP tab is detailed in the PCoIP Proxy post.
  3. Click Create when you’re done creating the Session Profile.

Create Session Policy

Once the Session Profile is created, you need a Session Policy linked to it. The Session Policy contains an expression, where if true, then the Session Profile is applied.

If multiple Session Policies apply to a particular connection, then the settings in the policies are merged. For conflicting settings, the Session Policy with the highest priority (lowest priority number) wins. Session Policies bound to AAA groups only override Session Policies bound to Citrix Gateway Virtual Servers if the AAA group bind point has a lower priority number. In other words, priority numbers are evaluated globally no matter where the Session Policy is bound. You can run the command nsconmsg –d current –g pol_hits to see which Session Policies are applying to a particular connection. See CTX214588 Understanding Session Policy Priority on Different Bind Points.

You can also include Endpoint Analysis expressions in a Session Policy, so that the Session Policy only applies to machines that pass the Endpoint Analysis scan. However, EPA Scans are only supported with Classic Syntax policy expressions, and not with Default Syntax.

To create a Session Policy that is linked to a Session Profile:

  1. On the left, go to Citrix Gateway > Policies > Session.
  2. In the right pane, switch to the Session Policies tab, and click Add.
  3. Give the policy a descriptive name.
  4. Change the Profile drop-down to the VPN Profile you just created.
  5. The Expression box has an option for switching to Default Syntax.

    1. If Default Syntax, enter true in the Expression box so it always evaluates to true. If Classic Syntax, it would be ns_true instead of true.
    2. If Default Syntax, you can enter HTTP.REQ.USER.IS_MEMBER_OF("MyADGroup") to restrict the Session Profile to members of a specific AD group. In Classic Syntax, this isn’t possible in an expression, and instead you must assign the Session Policy to a AAA Group.
  6. If Classic Syntax, you can add Endpoint Analysis scans to the Expression box. If the Endpoint Analysis scan succeeds, then the session policy is applied. If the Endpoint Analysis scan fails, then this session policy is skipped, and the next one is evaluated. This is how you can allow VPN if EPA scan succeeds, but all failed EPA scans will get a different session policy that only has ICA Proxy enabled.
    1. To add an Endpoint Analysis scan, use one of the Editor links on the right.
    2. Configure OPSWAT scans in the OPSWAT EPA Editor.
    3. Configure Client Security Expressions in the Expression Editor.
    4. You can combine multiple Endpoint Analysis scan expressions using Booleans (&&, ||, !).
  7. Click Create when done.

Bind Session Policy

Most of the Citrix Gateway configuration objects can be bound to a Citrix Gateway Virtual Server, AAA Groups, or both. This section details binding of Session Policies, but the other Citrix Gateway objects (e.g. Authorization Policies) can be bound using similar instructions.

  • Objects bound directly to the Citrix Gateway Virtual Server are evaluated for every user of that Gateway Virtual Server.
  • Objects bound to a AAA Group are only evaluated for members of that AAA Group.
    • Polices bound to AAA Groups usually have lower priority numbers than policies bound to Gateway Virtual Servers, so the AAA binding can override the Gateway binding.
    • However, objects/policies bound to a AAA Group are applied to every Gateway Virtual Server on the same appliance. To override AAA bindings at a specific Gateway, you can bind lower priority number policies to the Gateway Virtual Server.

Bind the new Session Policy to a Citrix Gateway Virtual Server, or a AAA group.

To bind to a Citrix Gateway Virtual Server

  1. Edit a Citrix Gateway Virtual Server (or create a new one).
  2. To make sure ICA Only is unchecked:
    1. Click the pencil icon for the Basic Settings section.
    2. Click More.
    3. Make sure ICA Only is unchecked, and click OK to close the Basic Settings section.
    4. Note: with this box unchecked, Gateway Universal licenses are now required for all users connecting through this Gateway Virtual Server.
  3. While editing the Gateway Virtual Server, consider changing the Portal Theme to RfWebUI. This changes the default portal page to look identical to StoreFront.
  4. Scroll down to the Policies section, and click the Plus icon.
  5. In the Choose Type page, ensure the Choose Policy drop-down is set to Session.
  6. Ensure the Choose Type drop-down is set to Request, and click Continue.
  7. Click where it says Click to select.

    1. If you already have Session Policies bound to this Gateway Virtual Server, then you might have to click Add Binding first.
  8. Click the radio button next to the previously created Session Policy, and click Select.
  9. Note: you cannot mix Classic Syntax Policies and Default Syntax Policies.
  10. In the Priority field, adjust the priority number. If you want this Session Policy to override other Session Policies, then set the priority number to a low value. See CTX214588 Understanding Session Policy Priority on Different Bind Points.
  11. Click Bind.
  12. If you already have Session Policies bound to the Gateway Virtual Server, then the list of Policies is displayed. If you don’t see this list, on the left, in the Policies section, click the line that says Session Policies.
  13. From this list, you can right-click the policies to Edit Binding (priority number), or Edit Profile.
  14. If your Citrix Gateway Virtual Server is configured with a Traffic Policy for Native OTP (One Time Passwords), change the Traffic Policy expression to the following. Source = Julien Mooren at NetScaler – Native OTP is breaking SSL VPN. 
    http.req.method.eq(post)||http.req.method.eq(get) && false

Bind to AAA Group

  1. To bind to a AAA Group, go to Citrix Gateway > User Administration > AAA Groups.
  2. On the right, add a AAA group with the same name (case sensitive) as the Active Directory group name. This assumes your LDAP policies/server are configured for group extraction (Group Attribute, and Sub Attribute).
  3. Edit the AAA Group.
  4. On the right, in the Advanced Settings column, add the Policies section.
  5. Click the plus icon to bind one or more Session Policies.
  6. If you want these Session Policies to override the Session Policies bound to the Citrix Gateway Virtual Server, then make sure the Session Policies bound to the AAA Group have lower priority numbers. See CTX214588 Understanding Session Policy Priority on Different Bind Points.


  7. If a user belongs to multiple groups, then for Advanced Session Policies, see CTX289931 AAA group session policies are not applying based on priority. Classic Policies in multiple AAA Groups are lumped together and evaluated based on bind point priority number. Advanced Policies are no longer lumped together and instead each AAA Group is evaluated separately. The first AAA Group created has higher priority than later created AAA Groups unless you specify the weight when creating the AAA Group from the CLI. 💡

Citrix Gateway Plug-in

Upgrade Citrix Gateway Plug-in

Citrix ADC pushes the Gateway Plug-in (aka VPN client) to client machines. In newer builds of Citrix ADC 13.0, you can upgrade the VPN plugin on the ADC without upgrading the ADC firmware.

  1. Download the latest plugin .tgz file from https://www.citrix.com/downloads/citrix-gateway/plug-ins/citrix-gateway-windows-plug-in-clients.html.
  2. In Citrix ADC, on the left click the Citrix Gateway node. On the right, click Upgrade EPA Libraries or EPA/VPN plugins.
  3. This page shows you the versions of the currently installed plugins.
  4. Click Choose File and select the win_vpn.tgz file. Click Upgrade.
  5. Click OK when prompted that the upgrade completed successfully.
  6. Go back to the Upgrade plug-in or EPA Libraries page to see the new versions.

Citrix Gateway Plug-in Installation

Here is what the user sees when launching the VPN session for the first time. This assumes the user is an administrator of the local machine.

  1. Wait for 10 seconds for the webpage to not detect Gateway Plug-in, and then click the Download button.
  2. Run the downloaded AGEE_setup.exe.
  3. In the Please read the Citrix Gateway Plug-in License Agreement page, click Install.
  4. In the Complete the Citrix Gateway Plug-in Setup Wizard page, click Finish.
  5. Click Yes to restart your system.
  6. In ADC 13.0 build 71.44 and newer, VPN plug-in for Windows supports Secure DNS update. This feature is disabled by default. To enable it, create the following on the client device: (source = 13.0-71.44 release notes) 💡
    • HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\Secure Access Client\secureDNSUpdate value of type REG_DWORD and set it to 1.
      • When you set the value to 1, the VPN plug-in tries the unsecure DNS update first. If the unsecure DNS update fails, the VPN plug-in tries the secure DNS update.
      • To try only the secure DNS update, you can set the value to 2.

Only administrators can install the Citrix Gateway Plug-in. You can download the Gateway plug-in from the NetScaler appliance at /var/netscaler/gui/vpns/scripts/vista and push it to corporate-managed machines. Or you can download VPN clients from Citrix.com. The VPN client version must match the Citrix ADC firmware version.

To deploy the Gateway Plug-in using Group Policy, see CTX124649 How to Deploy NetScaler Gateway Plug-in and Endpoint Analysis Installer Packages for Windows by Using Active Directory Group Policy.

While a VPN tunnel is established, you can open the Gateway Plug-in to see status. If the Gateway Plug-in is merged with Workspace app, right-click Workspace app, click Advanced Preferences, click Citrix Gateway Settings, and click Open.

Or, if the Gateway Plug-in icon is separated from Workspace app, then right-click the Gateway Plug-in icon, and click Open.

The hamburger menu on the left lets you see more info about the VPN tunnel.

If the Gateway VPN session isn’t established, you can open the Gateway plug-in, and login. No browser needed.

  • Gateway Plug-in 12.1 build 49 with Citrix ADC 12 build 49 support nFactor authentication (e.g. Native OTP) in the Gateway Plug-in. Older versions do not support nFactor.  💡

The Configuration page lets you enable Logging. Then the Logging page lets you collect the logs. See Citrix CTX138155 How to Collect Client VPN Logs for NetScaler Gateway.

VPN Client (Citrix Gateway Plug-in) Session Profile Settings

Separate Icons for Workspace app and Gateway

  1. By default, if Workspace app, and Citrix Gateway Plug-in, are installed on the same machine, then the icons are merged. To see the Citrix Gateway Plug-in Settings, you right-click Workspace app, open Advanced Preferences, and then click Citrix Gateway Settings. This makes it difficult to log off.

  2. You can configure the Session Profile to prevent the Citrix Gateway Plug-in from merging with Workspace app. Edit your VPN Session Policy/Profile. On the Client Experience tab…
  3. Scroll down, and check the box next to Advanced Settings.
  4. At the bottom of the General tab, check the box next to Show VPN Plugin-in icon with Receiver.
  5. This setting causes the two icons to be displayed separately thus making it easier to access the Citrix Gateway Plug-in settings, including Logoff.

Cleanup

  1. When the user logs off of VPN, a Cleanup page is displayed. This can be enabled or disabled in a Session Profile on the Client Experience tab.

  2. The cleanup options can be forced in a Session Profile on the Client Experience tab…
  3. Under Advanced Settings > Client Cleanup.

VPN Client Upgrades

  1. Whenever Citrix ADC firmware is upgraded, all users will be prompted to upgrade their VPN clients. You can edit a Session Policy/Profile, and on the Client Experience tab…
  2. Use the Upgrade drop-downs to disable the automatic upgrade.
  3. The Plugin Upgrade settings are also configurable in the Gateway Virtual Server…
  4. In the Basic Settings > More section.


Authorization Policies

If your Session Profile has Security tab > Default Authorization Action set to Deny (recommended), then create Authorization Policies to allow access across the tunnel.

  1. On the left, under Citrix Gateway, expand Policies, and click Authorization.
  2. On the right, click Add.
  3. Name the Authorization Policy.
  4. Select Allow or Deny.
  5. For the Expression, Citrix Gateway supports both Classic Syntax and Default Syntax.
    • Default Syntax gives you much greater flexibility in matching the traffic that should be allowed or denied. Hit Control+Space on your keyboard to begin building a Default Syntax expression. You typically want to identify traffic based on Destination IP Address, Destination Port Number, HTTP Request URL, HTTP Host Header, etc. Common expressions include:
      • CLIENT.IP.DST.IN_SUBNET()
      • CLIENT.TCP.DSTPORT.EQ()
      • You can also use HTTP.REQ.USER.IS_MEMBER_OF("MyADGroup") in your expressions.
    • CTX232237 NetScaler Unified Gateway Advanced Authorization Policy Support for UDP/ICMP/DNS Traffic explains new types of Authorization Policies in NetScaler 12.0 build 56 and newer.
      • CLIENT.UDP.DSTPORT.EQ(2080)
      • CLIENT.IP.PROTOCOL.EQ(ICMP)
      • CLIENT.UDP.DNS.DOMAIN.CONTAINS("citrix")
    • Note: you cannot mix both Classic Syntax and Default Syntax. You must unbind every Classic Syntax Authorization Policy before you can bind Default Syntax Authorization Policies.
  6. Click Create when done.
  7. Authorization Policies are usually bound to AAA groups. This allows different groups to have different access across the tunnel.
    1. Or, you can use HTTP.REQ.USER.IS_MEMBER_OF("MyADGroup") in your Default Syntax expressions.
  8. Edit a AAA Group at Citrix Gateway > User Administration > AAA Groups.
  9. On the right, in the Advanced Settings column, add the Authorization Policies section.
  10. Then click where it says No Authorization Policy to bind policies.

Intranet Applications

If you enabled Split Tunnel, then you’ll need to create Intranet Applications to specify which traffic goes through the tunnel.

  1. On the left, under Citrix Gateway, expand Resources, and click Intranet Applications.
  2. On the right, click Add.

    1. Enter a name for the Internal subnet.
    2. Change the Interception Mode to TRANSPARENT.
    3. Enter an IP subnet. Only packets destined for this network go across the tunnel.
      1. You typically specify a summary address for all internal subnets (e.g. 10.0.0.0/8).
      2. Alternatively, you can define minimal Intranet Application destinations as a security mechanism (assuming Split Tunnel is enabled), but Authorization Policies are more appropriate for that task.
  3. Click Create.
  4. Create additional Intranet applications for each internal subnet.
  5. Intranet Applications are usually bound to the Gateway Virtual Server, but you can also bind them to AAA Groups.
  6. On the right, in the Advanced Settings column, add the Intranet Applications section.
  7. On the left, click No Intranet Application to bind Intranet Applications.

DNS Suffix

Specify a DNS Suffix for Split DNS to function with single label DNS names. Citrix Gateway adds these DNS suffixes to DNS queries across the VPN tunnel.

  1. On the left, under Citrix Gateway, expand Resources, and click DNS Suffix.
  2. On the right, click Add.
  3. Enter the DNS Suffix, and click Create. You can add multiple suffixes.

Bookmarks

Bookmarks are the links that are displayed in the default portal interface. They can point to websites, or RDP addresses. PCoIP bookmarks come from VMware Horizon Connection Server. ICA bookmarks come from Citrix StoreFront.

  1. Under Citrix Gateway, expand Resources, and click Bookmarks.
  2. On the right, click Add.

    1. Give the bookmark a name, and display text.
    2. Enter a website or RDP address.
    3. Optionally browse to an Icon file.
    4. You typically need to check Use Citrix Gateway As a Reverse Proxy, especially for Clientless Access (rewrite without VPN) to an internal website.
    5. The other fields are for Single Sign-on through Unified Gateway.
  3. Click Create.
  4. Bookmarks (aka Published Applications > Url) are usually bound to AAA groups so different groups can have different bookmarks. But it’s also possible to bind Bookmarks to Citrix Gateway Virtual Servers.
  5. If Citrix Gateway Virtual Server, add the Published Applications section to bind Bookmarks (Url).
  6. For AAA Group, it’s the Bookmarks section.
  7. On the left, find the Published Applications section, and click No Url to bind Bookmarks.

VPN Client IP Pools (Intranet IPs)

By default, Citrix Gateway VPN clients use Citrix ADC SNIP as their source IP when communicating with internal resources. To support IP Phones or endpoint management, you must instead assign IP addresses to VPN clients.

Any IP pool you add to Citrix Gateway must be reachable from the internal network. Configure a static route on the upstream router. The reply traffic to VPN Client IPs should be routed through a Citrix ADC SNIP. Or the Citrix ADC can participate in OSPF.

When a client is assigned a client IP, this IP address persists across multiple sessions until the appliance reboots, or until the appliance runs out of IPs in the pool.

  1. Edit a Citrix Gateway Virtual Server, or a AAA group.
  2. On the right, in the Advanced Settings section, click the plus icon next to Intranet IP Addresses.
  3. On the left, click where it says No Intranet IP.
  4. Enter a subnet and netmask. Click Bind.
  5. In a Session Profile, on the Network Configuration tab, check the box next to Advanced Settings.
  6. Use the Intranet IP drop-down to configure the behavior when there are more VPN clients than available IPs in the address pool.

    1. If you set it to NOSPILLOVER, then users can only have one VPN session, as described in CTX218066 How to Limit One Session Per User on NetScaler Gateway?.


  7. To see the Client IP address, on the client side, after the tunnel is established, right-click the Citrix Gateway Plug-in, and click Open.
  8. See the Internal network address.
  9. To see the client IP on the Citrix ADC, go to Citrix Gateway, and on the right is Active user sessions.
  10. Select one of the views, and click Continue.
  11. The right column contains the Intranet IP.

StoreFront in Gateway Clientless Access Portal

If you enabled the RfWebUI theme, then no StoreFront configuration is necessary.

But if you want to embed StoreFront in the other Gateway themes (X1, Default, Green Bubble), then follow these instructions.

  1. On StoreFront, edit the file C:\Inetpub\wwwroot\Citrix\StoreWeb\web.config.
    1. On the bottom, there are three sections containing X-Frame-Options. Change all three of them from deny to allow.
    2. Also change frame-ancestors from none to self.
  2. In Citrix ADC, go to Citrix Gateway > Global Settings, and click Configure Domains for Clientless Access.
  3. Change the selection to Allow Domains, enter your StoreFront FQDN, and click the plus icon.
  4. Click OK.
  5. In a Session Policy/Profile:
    1. On the Client Experience tab, make sure Single Sign-on to Web Applications is enabled.
    2. On the Published Applications tab, configure the Web Interface Address to point to the StoreFront Receiver for Web page.
    3. Configure the Single Sign-on domain to match what’s configured in StoreFront.
    4. You might have to override the Web Interface Portal Mode.
  6. The Applications page of the 3-page portal (e.g. X1 theme) should automatically show the StoreFront published icons.

Quarantine Group

Citrix Gateway can be configured so that if Endpoint Analysis scans fail, then the user is placed into a Quarantine Group. You can bind session policies, authorization policies, etc. to this quarantine group. Policies bound to other AAA groups are ignored.

  1. Go to Citrix Gateway > User Administration > AAA Groups.

    1. Add a new local group for your Quarantined Users. This group is local, and does not need to exist in Active Directory.
    2. Bind session policies, authorization policies, etc. to your quarantine AAA group. These policies typically allow limited access to the internal network so users can remediate. Or, it might simply display a webpage telling users how to become compliant.
    3. The Session Policy bound to the Quarantine Group is usually different than the Session Policies bound to other AAA groups. You can use the variation in Session Policy names for SmartAccess.
      1. One option is to configure the Delivery Groups > Access Policy so that icons are shown for Session Policies bound to non-quarantine AAA Groups, but not for the Session Policy that is bound to the Quarantine Group.
      2. Another option is to configure Citrix Policies > Access Control to disable functionality for the Quarantine Group Session Policy, but not for other AAA Group Session Policies.
  2. Create or edit a Session Profile to include a Client Security Expression that checks for compliance.
    1. In the Session Profile, on the Security tab, check the box next to Advanced Settings.
    2. Scroll down, and check the box to the right of Client Security Check String.
    3. Use the Editor links to add an Endpoint Analysis expression.
    4. Just below the Client Security Check String, select the previously created Quarantine Group. If the Client Security Check String EPA Scan fails, then the failed users are added to the Quarantine Group and removed from all other AAA Groups.
  3. Click Create when done creating or editing the Session Profile.
  4. Create a Session Policy for the Session Profile that contains the Client Security Check String.
    1. Enter ns_true as the expression.
    2. Then click Create.
  5. Edit your Gateway Virtual Server, and bind the Session Policy/Profile that has the Client Security Check String configured.


  6. To troubleshoot Quarantine policies, use the command nsconmsg –d current –g pol_hits.
  7. Citrix ADM Gateway Insight shows users that failed EPA scans, and their quarantine status.

Related Pages

RDP Proxy – Citrix Gateway

Last Modified: Apr 16, 2021 @ 2:23 pm

95 Comments

This article applies to Citrix Gateway 13.0, Citrix Gateway 12.1, and NetScaler Gateway 12.0. Citrix ADC is the new name for NetScaler. Citrix Gateway is the new name for NetScaler Gateway.

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RDP Proxy Overview

Citrix ADC supports RDP Proxy through Citrix Gateway. No VPN required. RDP can connect through Citrix Gateway on port 443.

There are several ways of launching RDP sessions through Citrix Gateway RDP Proxy:

  • Bookmarks on the Clientless Access portal page.
    • Bookmarks can be defined by the administrator.
    • Or users can add their own RDP bookmarks.
  • After logging in, change the URL in the browser to /rdpproxy/MyRDPServer. MyRDPServer can be IP or DNS.
  • In the RfWebUI Portal Theme, the Bookmark link lets users enter an RDP address, and click Go.

Links:

Requirements

Here are some requirements for RDP Proxy:

  • Citrix ADC Advanced Edition or Premium Edition.
    • Citrix Gateway Enterprise VPX is not sufficient. It must be a full ADC license.
  • Citrix Gateway Universal Licenses for each user.
    • Most Citrix ADC Editions come with built-in Gateway Universal licenses: Citrix ADC Standard Edition = 500 licenses, Citrix ADC Advanced Edition = 1000 licenses, and Citrix ADC Premium Edition = unlimited licenses. See Feature Licensing in the Gateway Tweaks post.
  • TCP 443 opened to the Citrix Gateway Virtual Server.
  • TCP 3389 opened from the Citrix ADC SNIP to the RDP Servers.

Configuration

Enable RDP Proxy Feature

  1. Go to System > Settings, and click Configure Advanced Features.
  2. In the left column, near the bottom, check the box for RDP Proxy and click OK.

Create RDP Server Profile

You do not need a RDP Server Profile if the machines you want to RDP to are not members of any RDS Connection Broker Infrastructure. Skip to the next section to create the RDP Client Profile.

If you want Citrix Gateway to RDP Proxy to a RDSH machine that is part of an RDS Connection Broker Infrastructure (aka RDS Collection, or member of RDS Broker Farm), then you’ll need the following:

  • Citrix ADC 12.1 or newer
    • NetScaler 12.0 does not support RDSH machines connected to RDS Connection Broker.
  • RDP Server Profile to enable the 3389 listener on your Gateway Virtual Server.

RDP connections through Citrix Gateway to RDP Connection Broker members requires that the Remote Desktop Session Hosts are configured to disable the GPO setting Use IP Address Redirection located in a GPO at Computer Configuration | Policies | Administrative Templates | Windows Components | Remote Desktop Services | Remote Desktop Session Host | RD Connection Broker. Disable this setting on the RDSH machines, not the Connection Broker machine. Disabling this setting enables token-based redirection instead of IP-based redirection, which is required by RDP Proxy in Citrix Gateway.

To create the RDP Session Profile on Citrix ADC:

  1. Expand Citrix Gateway, expand Policies, and click RDP.
  2. On the right, on the Server Profiles tab, click Add.
  3. In the Create RDP Server Profile window:
    1. Give the RDP Server Profile a name.
    2. If you don’t enter an RDP IP, then it will use the Gateway VIP.
    3. If you don’t enter a RDP Port, then it will default to 3389. This is an additional port that must be opened on the firewall.
    4. Enter a new Pre Shared Key.
    5. Change RDP Redirection to ENABLE. This is a new feature in ADC 12.1. This setting enables RDS Infrastructure to work.
  4. Click Create.

Create RDP Proxy Client Profile

All RDP Proxy configurations need an RDP Client Profile.

  1. Expand Citrix Gateway, expand Policies, and click RDP.
  2. On the right, switch to the Client Profiles tab, and click Add.

    1. Give the RDP Client Profile a name, and configure the client device mappings as desired. Scroll down.
    2. For the RDP Cookie Validity field, Citrix CTX233207 says that after a HA failover, RDP Proxy session will not reconnect if the cookie has expired.
    3. If you are running ADC 12.1 or newer and need to allow RDP connections to RDS Infrastructure member machines, then enter the same Pre Shared Key that you configured in the RDP Server Profile. If you don’t need to RDP to any member of any RDS Infrastructure, then you don’t need these settings.
      • Also, for RDP Host, enter the FQDN of the Gateway Virtual Server. This is only needed for RDP Server Profiles.
    4. Click Create.

Create RDP Bookmarks

You can create administrator-defined bookmarks that can be assigned to everybody or can be assigned to specific Active Directory groups. Another option is to let each user create their own bookmarks.

  1. On the left, expand Citrix Gateway, expand Resources, and click Bookmarks.

  2. On the right, click Add.

    1. Give the Bookmark a name.
    2. For the URL, enter rdp://MyRDPServer using IP or DNS (FQDN).
      • For RDS Collections, enter the address of any RDP member of the collection. The RDP server will ask the Connection Broker to load balance across the Collection and then redirect the RDP connection to the least busy RDP server in the Collection.
      • For RemoteApp, see Citrix Discussions. Example URL: 
        rdp://rdshost1.comtoso.com?alternate shell:s:||win32calc&remoteapplicationprogram:s:||win32calc&remoteapplicationname:s:Calculator&remoteapplicationcmdline:s:&remoteapplicationmode:i:1
    3. Check the box next to Use Citrix Gateway As a Reverse Proxy,
  3. Click Create.
  4. Create more bookmarks as desired.

Edit a Session Profile

  1. Create or edit a Gateway Session Profile (Session Profiles tab).
  2. On the Security tab, set Default Authorization Action to ALLOW. Or you can use Authorization policies to control access.

  3. On the Remote Desktop tab, check Override Global, and select the RDP Client Profile you created earlier.
  4. On the Client Experience tab, set Clientless Access to On. This enables the clientless access portal that can display administrator-defined bookmarks and lets users add their own bookmarks.
  5. On the Client Experience tab of the Session Profile, decide if you want Single Sign-on to Web Applications or not. It’s required for RDS Collections but optional for RDP machines that are not members of an RDS Infrastructure. If not checked then the user will be prompted to login again when launching an RDP session.
  6. On the Published Applications tab, make sure ICA Proxy is OFF so the clientless portal is displayed.
  7. Click OK when done.

Edit Citrix Gateway Virtual Server

  1. Edit or Create your Gateway Virtual Server.
  2. In the Basic Settings section, click the pencil icon on the top right to edit it.
  3. Click More to show more settings.

    1. If the machines you are RDPing to are not members of an RDS Collection, then don’t configure RDP Server Profile. With no RDP Server Profile configured the RDP connections will be 443 to the Gateway. If you instead configure an RDP Server Profile then the RDP Connections will be 3389 or whatever port number you put in the RDP Server Profile.
    2. If you want to allow RDP to RDS Collection members, then select the RDP Server Profile that you created earlier. The RDP Server Profile enables port 3389 on the Gateway VIP. If you don’t select a RDP Server Profile, then RDP is proxied through 443 on the Gateway, but this won’t work for RDS Collection members.
    3. Scroll down. Make sure ICA Only is not checked. This means you’ll need Citrix Gateway Universal licenses for each user that connects through this Gateway.
    4. Click OK to close the Basic Settings section.
  4. Bind a certificate.
  5. Bind authentication policies.
  6. In the Policies section, bind the Session Policy that has the RDP Client Profile configured. Be mindful of policy priority.


  7. You can bind RDP Bookmarks to either the Citrix Gateway Virtual Server, or to a AAA group. To bind to the Citrix Gateway Virtual Server, on the right, in the Advanced Settings section, click Published Applications.
  8. On the left, in the Published Applications section, click where it says No Url.
  9. Bind your Bookmarks.
  10. While editing your Gateway vServer, you can also set the Portal Theme to RfWebUI. This is strongly recommended for the clientless access portal that displays the RDP bookmarks.

Configure DNS

  1. If you want to connect to RDP servers using DNS, make sure DNS servers are configured on the appliance (Traffic Management > DNS > Name Servers).
  2. If you want to use the short names instead of FQDNs, add a DNS Suffix (Traffic Management > DNS > DNS Suffix).

Use RDP Proxy

  1. Connect to your Citrix Gateway and login.
  2. If you configured Bookmarks, if RfWebUI theme, on the Apps tab, click Web and SaaS Apps.

    1. If X1 theme, the bookmarks are on the Web Apps page.
  3. If RfWebUI theme, you can click Details to mark the Bookmark as a Favorite.

  4. Or you can change the address bar to /rdpproxy/MyRDPServer. You can enter an IP address (e.g. rdpproxy/192.168.1.50) or a DNS name (/rdpproxy/myserver).
  5. If you edit the downloaded .rdp file, notice that it’s connecting on port 443.
  6. Then open the downloaded .rdp file.
  7. You can view the currently connected RDP users by going to Citrix Gateway > Policies > RDP, and on the right is the Connections tab.

Personal Bookmarks

  1. If using the RfWebUI theme, another way to launch RDP sessions is to click the Bookmark link, enter a destination DNS/IP, check the box next to RDP Link, and click Go.
  2. You can also give the Bookmark a name and Save it.
  3. Then access the saved bookmark from Apps > Personal Bookmarks.

  4. Personal bookmarks are stored in /var/vpn/bookmark on the appliance. You might want to back these up and replicate them to other Gateway appliances participating in GSLB. See NetScaler 11.1 Personal Bookmarks at Citrix Discussions.
  5. The X1 theme has an Add button on the Web Apps page.
  6. But there is no Go button. Instead, you save the Bookmark and launch it from the list.

SmartAccess / SmartControl – Citrix Gateway

Last Modified: Aug 3, 2024 @ 9:39 am

55 Comments

This article applies to NetScaler Gateway 14.1, Citrix Gateway 13.x, Citrix Gateway 12.1, and NetScaler Gateway 12.0.

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SmartAccess / SmartControl

SmartAccess and SmartControl let you change ICA connection behavior (e.g. disable client device mappings, hide icons) based on how users connect to Citrix Gateway. Decisions are based on Citrix Gateway Virtual Server name, Session Policy name, and Endpoint Analysis scan success or failure.

SmartAccess vs SmartControl:

  • SmartAccess lets you control visibility of published icons, while SmartControl does not.
  • SmartControl is configured exclusively on Citrix Gateway, while SmartAccess requires configuration on both Citrix Gateway, and inside Citrix Studio.
  • SmartControl requires Citrix ADC Premium Edition licensing, while SmartAccess is available in all Citrix ADC Editions.
    • Both features require Citrix Gateway Universal licenses for every concurrent connection.

Prerequisites

Both SmartAccess and SmartControl have the same prerequisites. You can configure SmartAccess in Citrix Virtual Apps and Desktops (CVAD) at any time, but it won’t work, until you do the following:

  1. Citrix ADC appliance license: See Feature Licensing in the Gateway Tweaks post. In summary:
    • SmartAccess is available in all editions of Citrix ADC appliances.
    • SmartControl is available only in Citrix ADC Premium Edition.
  2. Citrix Gateway Universal Licenses – On the Citrix ADC, go to System > Licenses, and make sure you have Citrix Gateway Universal Licenses allocated to the appliance.
    1. Most Citrix ADC Editions (except Citrix Gateway Enterprise VPX) come with built-in Gateway Universal licenses: Citrix ADC Standard Edition = 500 licenses, Citrix ADC Advanced Edition = 1,000 licenses, and Citrix ADC Premium Edition = unlimited licenses.
    2. Additional Citrix Gateway Universal licenses can be acquired through other means. See Feature Licensing in the Gateway Tweaks post for details.
    3. The Universal licenses are allocated to the hostname of the appliance (click the gear icon to change it), not the MAC address. In a High Availability pair, if each node has a different hostname, then you can allocate the licenses to one hostname, then reallocate to the other hostname. See Feature Licensing in the Gateway Tweaks post for details.
  3. Citrix Gateway must have ICA Only unchecked.
    1. On the Citrix ADC, go to Citrix Gateway > Virtual Servers, and edit your Gateway Virtual Server.
    2. In the Basic Settings section, click the pencil icon.
    3. Click More.
    4. Uncheck the box next to ICA Only, and click OK. This tells Citrix Gateway to start using Universal licenses and enables the SmartAccess and SmartControl features.
  4. Enable Trust XML on the Citrix Virtual Apps and Desktops (CVAD) Site/Farm:
    1. On a CVAD Controller, run PowerShell as Administrator.
    2. Run asnp citrix.* to load the snapins.
    3. Run Set-BrokerSite -TrustRequestsSentToTheXmlServicePort $true to enable Trust XML.
  5. Configure Callback URL in StoreFront:
    1. In StoreFront Console, right-click the Stores node, and click Manage Citrix Gateways.
    2. Edit a Gateway.
    3. On the Authentication Settings page, make sure a Callback URL is configured. The Callback URL must resolve to a Citrix Gateway VIP on the same appliance that authenticated the user. The Callback Gateway’s certificate must match the FQDN entered here. If you are configuring Single FQDN for internal and external, then the Callback FQDN must be different than the Single FQDN.

Once the prerequisites are in place, do the following as detailed below:

Endpoint Analysis

Endpoint Analysis (EPA) scans are completely optional. You can configure SmartControl and SmartAccess without implementing any Endpoint Analysis.

Endpoint Analysis is supported on Windows and Mac devices. Other devices, like iOS and Android, do not support Endpoint Analysis. If you want to allow mobile device connectivity, then make sure you have an access mechanism (e.g. ICA Proxy) that works if the Endpoint Analysis scan fails.

Citrix ADC 12.1 and newer support two methods of doing EPA: nFactor EPA, or Classic EPA. Classic EPA will no longer be supported in ADC 13.1 and newer so you should eventually switch to nFactor EPA.

Workspace app on Windows supports EPA when configured using nFactor EPA. Workspace app does not support Classic EPA.

nFactor EPA

EPA can be one of the factors of an nFactor flow. EPA can be performed before authentication, or after authentication.

EPA doesn’t work on iOS/Android. To skip those platforms, see CTX572334 Eliminate Advanced Endpoint Analysis scans on Mobile devices/iOS.

  1. Create an nFactor EPA Action.
    1. The easiest way to find EPA is to use the Search box on the top of the left menu. Or, navigate to Security > AAA > Policies > Authentication > Advanced Policies > EPA.
    2. The EPA Editor link on the right-side of the Expression box lets you configure EPA Expressions. See OPSWAT EPA Expressions below for more details on how to configure an Opswat expression.
    3. For SmartAccess based on the results of the EPA scan, configure the Default Group field with a new group name (doesn’t exist in Active Directory). You’ll later use the Group name in a Session Policy and use the Session Policy name in your Citrix Policy Access Filters or Delivery Group Access Control. Default Group probably only works if the EPA Factor is performed after authentication.
  2. After creating an EPA Action, create an Advanced Authentication Policy of type EPA and select the EPA Action you created earlier.
    1. The expression is either true, or an expression that defines who needs EPA scanning. If you are configuring post-authentication EPA, then you can use group membership (e.g. AAA.User.Is_Member_Of()) expressions.

  3. Create a Policy Label for the EPA Factor. Login Schema should be LSCHEMA_INT.

    1. Bind the EPA Policy to your Policy Label.
    2. If you don’t bind any other policies, then if EPA fails, then the user shown the Access Denied page. If you want authentication to continue even with a failed EPA scan, then bind another policy to the Policy Label.
    3. Create an Advanced Authentication Policy named similar to NoAuth and change Action Type to NO_AUTHN. Expression = true. Bind the NoAuth policy to the Policy Label.
    4. The final Policy Label should have an EPA Factor with Goto = NEXT and the second policy as NoAuth.
  4. In earlier factors that authenticate the user, when binding an authentication policy, click in the Select Next Factor field and select your EPA Policy Label.

    • In the earlier authentication factor, edit the Login Schema Profile, click More, and check the box next to Enable Single Sign On Credentials. EPA as later factor overrides the password collected in earlier factors causing Single Sign-on to StoreFront to fail and this checkbox fixes that problem.
  5. Create a Citrix Gateway Session Policy that is applied when the EPA factor succeeds.
    1. Go to Citrix Gateway > Policies > Session.
    2. On the tab named Session Profiles, click Add.
    3. Name it FullAccess or similar and click Create. The Session Profile does not need any settings.
    4. Switch to the tab named Session Policies and click Add.
    5. Select the Profile you just created.
    6. If you are doing Advanced Policies, then the Expression is AAA.USER.IS_MEMBER_OF(“GroupName”) where “GroupName” is the name of the Default Group you specified when you created the EPA Action. Click Create. If you are doing Classic Policies, then the expression is ns_true.
  6. If your session policy is Advanced syntax, then bind the Session Policy to your Gateway vServer.
    1. Go to Citrix Gateway > Virtual Servers and edit an existing vServer.
    2. Scroll all the way down to the Policies section and click the Session Policies line.
    3. Add Binding and select the Session Policy you will use for SmartAccess. Priority doesn’t matter.
  7. For both Advanced Session Policies and Classic Session Policies, create a AAA Group that matches the Default Group you specified in the EPA Action. CTX278960 says this is also required for IS_MEMBER_OF expressions.
  8. If you are doing Classic Session Policies, then create bind the Session Policy to the AAA Group. If you are doing Advanced Session Policies bound directly to the Gateway Virtual Server, then you don’t need to bind anything to the AAA Group.
  9. You can now use the Session Policy in your SmartAccess configuration. See the SmartAccess section below for more details.

Classic EPA Policies

There are two methods of Classic Endpoint Analysis: pre-authentication and post-authentication. For pre-authentication, configure an Endpoint Analysis expression in a Preauthentication Policy. For post-authentication, configure the Endpoint Analysis expression on one or more Session Policies.

  • With a Preauthentication Policy, if the Endpoint Analysis scan fails, then users can’t login.
  • With a Postauthentication Policy, Endpoint Analysis doesn’t run until after the user logs in. Typically, you create multiple Session Policies. One or more Session Policies have Endpoint Analysis expressions. Leave one policy without an Endpoint Analysis expression so there’s a fallback in case the client device doesn’t support Endpoint Analysis (e.g. mobile devices). The name of the Session Policy is then used later in Citrix Policies and Citrix Delivery Groups.
    • Inside the Session Profile is a field for Client Security expression, which supports an EPA expression. This field is for VPN only, and does not affect SmartAccess.

Preauthentication Policies and Profiles are configured at Citrix Gateway > Policies > Preauthentication.

  1. On the right, switch to the Preauthentication Profiles tab, and create a Preauthentication Profile to allow access.

  2. Switch to the Preauthentication Policies tab, and create a Preauthentication Policy with an EPA expression. Select the Request Action that allows access.

  3. The right side of the Expression box has links to create EPA expressions, as detailed below.

Classic Post-authentication Policies and Profiles are configured at Citrix Gateway > Policies > Session.

  1. When creating a Session Policy, the right side of the Expression box has links to create EPA expressions, as detailed below.
  2. Classic Syntax vs Default Syntax – EPA expressions can only be added to Classic Syntax Policies. If you click Switch to Default Syntax, then the OPSWAT EPA Editor disappears. Use nFactor EPA instead.
  3. If you edit a Session Profile, on the Security tab…
  4. Under Advanced Settings, you will see a Client Security Check String box that lets you enter an EPA Expression. This field applies only to VPN and does not affect SmartAccess. Also, this field does not function if your Session Policy is Advanced instead of Classic.

EPA Expressions

Citrix ADC has two Endpoint Analysis engines: the original Client Security engine, and the newer OPSWAT EPA engine.

OPSWAT EPA Expressions

To configure OPSWAT EPA expressions:

  1. When creating an nFactor EPA Action, click the EPA Editor link.

    • When creating a Classic Preauthentication Policy, or Session Policy, click the OPSWAT EPA Editor link.
  2. Use the drop-down menus to select the scan criteria.
  3. You will see some fields with a plus icon that lets you configure more details for the scan.

    • Note: the text in these policy expressions is case sensitive.
  4. Then click Done.

Additional OPSWAT EPA Info

See the following links for more Advanced EPA information:

Original Client Security Expressions

To configure the original Client Security expressions:

  1. When creating a Classic Preauthentication Policy or Classic Session Policy, click the Expression Editor link.
  2. Change the Expression Type to Client Security.
  3. Use the Component drop-down to select a component.
    1. A common configuration is to check for domain membership as detailed at Citrix CTX128040 How to Configure a Registry-Based Scan Expression to Look for Domain Membership.
    2. Citrix CTX128039 How to Configure a Registry-Based EPA Scan Expression on NetScaler to Look for the Active Device or Computer Name of an Explicit Workstation

Once the Classic Preauthentication and/or Classic Session Policies are created, bind them to your Citrix Gateway Virtual Server:

  1. Edit a Citrix Gateway Virtual Server.
  2. Scroll down to the Policies section, and click the plus icon.
  3. Select either Preauthentication or Session, and select the policy you already created. Then click Bind.
  4. Session Policies with EPA Expressions are typically higher in the list (lower priority number) than non-EPA Session Policies.

EPA Libraries

In NetScaler 12.0 build 57 and newer, the EPA Libraries are updated out-of-band.

  1. Download the latest EPA libraries.
  2. In the Citrix ADC menu, click the Citrix Gateway node.
  3. On the right, in the left column, click Upgrade EPA Libraries.
  4. Click Choose File
  5. Browse to one of the .tgz library files, and click Open.
  6. Click Upgrade.
  7. Click OK when prompted that EPA Library upgraded successfully.
  8. Click Upgrade EPA Libraries again.
  9. Click Choose File.
  10. Browse to the other .tgz EPA library file, and click Open.
  11. Click Upgrade.
  12. Click OK when prompted that upgraded successfully.
  13. To see the versions, click Upgrade EPA Libraries.

EPA Plug-in

The EPA plug-in is automatically deployed when the user connects to Citrix Gateway – either before the logon page, or after the logon page.

To pre-deploy EPA plug-in, see CTX124649 How to Deploy NetScaler Gateway Plug-in and Endpoint Analysis Installer Packages for Windows by Using Active Directory Group Policy. This article describes how to extract the plug-in .msi file, and deploy using Group Policy.

EPA and Portal Themes

The webpages displayed to the user when downloading the EPA plug-in and running the EPA plug-in can be customized by editing a Portal Theme.

Look in the Advanced Settings column on the right for the three EPA pages. Citrix CTX222812 How to Customize Custom Error Messages for NetScaler Gateway EPA Scans.

EPA Troubleshooting

From Citrix CTX209148 Understanding/Configuring EPA Verbose Logging Feature:

  1. Go to Citrix Gateway > Global Settings.
  2. On the right, click Change Global Settings.
  3. On the Security tab, click Advanced Settings.
  4. Scroll down, check the box next to Enable Client Security Logging, and click OK.
  5. When the scan fails, the user is presented with a Case ID.
  6. You can then grep /var/log/ns.log for the Case ID. Or search your syslog.

For client-side logging, on the client machine, go to HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\Secure Access Client.

  • Make a DWORD value named “EnableEPALogging“, and set the value to 1.
  • After attempting the scan again, you’ll find the file %localappdata%\Citrix\AGEE\epaHelper_epa_plugin.txt with details for each scan expression.

NetscalerAssasin EPA OPSWAT Packet flow and Troubleshooting shows a Wireshark trace of an EPA scan.

SmartAccess

Links:

Make sure the prerequisites are completed. This includes:

  • ICA Only unchecked on Citrix Gateway Virtual Server
  • Gateway Universal licenses installed
  • Callback URL configured at StoreFront
  • Trust XML enabled on Delivery Controllers

SmartAccess is configured in two places:

  • Delivery Group > Access Policy page in Web Studio in CVAD 2407 and newer has been redesigned. There are built-in Access Policies that you can edit. And you can add Access Policies. They support both inclusions and exclusions. See Citrix Docs for details.

    • CVAD 2402 and older looks like the screenshot below.
  • Citrix Policy (user settings only) > filters > Access control in Web Studio looks like the screenshot below.

    • Group Policy looks like the screenshot below.

In any case, you enter the name of a matching Gateway Virtual Server, and the name of a matching Session Policy (or Preauthentication Policy).

  • Set AG farm name or Site or Farm name to the name of the Citrix Gateway Virtual Server.
  • Set Access condition or Filter to the name of the Citrix Gateway Session Policy (or Preauthentication Policy).
  • You can use * as a wildcard in either field.
  • The matching Citrix Gateway Session Policy typically has an EPA Factor in an nFactor flow that puts the user in a AAA Group that has a group-specific Session Policy bound to the AAA group. That way the Session Policy only applies to connections that match the EPA Expression.

Icon visibility – Access Control at the Delivery Group controls visibility of icons published from that Delivery Group.

  • Access Control on a Delivery Group is Allow only. Icons are hidden from non-matching connections.
  • You can uncheck Connections through Citrix Gateway to hide the published icons from all Citrix Gateway connections.
  • It’s not possible to hide individual published applications. You can hide all applications from a single Delivery Group, or none of them. If you need more granularity, then you’ll have to split the applications onto different Delivery Groups.
  • App Groups do not have an Access Control option. It’s Delivery Groups only.

Citrix Policy Settings – Access Control filter on a Citrix Policy determines if the Policy settings apply or not.

  • Access Control filter applies to User Settings only. It’s not configurable for Computer Settings.
  • You typically configure the Unfiltered Citrix Policy to block all client device mappings. Then you configure a higher priority Citrix Policy with Access Control filter to re-enable client device mappings for endpoint machines that match the Session Policy and EPA Expression.

When connected to a session, Director shows SmartAccess Filters on the Session Details page. Notice the Farm Name (Gateway Virtual Server name) and Filter Name (Session Policy name)

SmartControl

The SmartControl feature lets you configure some of the SmartAccess functionality directly on the appliance. See Configuring SmartControl at Citrix Docs for detailed instructions.

  • Note: SmartControl requires Citrix ADC Premium Edition. If you don’t have Premium Edition, you can instead configure SmartAccess.
  • SmartControl cannot hide published icons. If you need that functionality, configure SmartAccess, either as a replacement for SmartControl, or as an addition to SmartControl.

To configure SmartControl:

  1. Make sure the Prerequisites are completed. This includes: ICA Only unchecked and Gateway Universal licenses installed. Callback URL and Trust XML are not needed.
  2. If you are using a Preauthentication Policy to run an Endpoint Analysis scan:
    1. Edit the Preauthentication Profile.
    2. Configure the Default EPA Group with a new group name. You’ll use this group name later.
  3. If you are instead using a Session Policy to run the post-authentication Endpoint Analysis scan:
    1. Edit the Session Profile
    2. On the Security tab, use the Smartgroup field to define a new group name for users that pass the scan. You’ll use this group name later.
  4. On the left, expand Citrix Gateway, expand Policies, and click ICA.
  5. On the right, switch to the Access Profiles tab, and click Add.

    1. Configure the restrictions as desired, and click Create.
  6. Switch to the ICA Action tab, and click Add.

    1. Give the ICA Action a name.
    2. Select the ICA Access Profile.
    3. Click Create.
  7. Switch to the ICA Policies tab, and click Add.
  8. In the Create ICA Policy page, do the following:
    1. Give the ICA Policy a name.
    2. Select the previously created ICA Action.
    3. Enter an expression. You can use HTTP.REQ.USER.IS_MEMBER_OF(“MyGroup”).NOT where MyGroup is the name of the SmartGroup you configured in the session profile or preauth scan.
  9. Click Create when done.
  10. Edit your Gateway Virtual Server.
    1. Scroll down to the Policies section, and click the plus icon.
    2. Change the Choose Type drop-down to ICA, and click Continue.
    3. Select the SmartControl policy you created earlier, and click Bind.

Related Pages

EUC Weekly Digest – August 26, 2017

Last Modified: Nov 7, 2020 @ 6:34 am

Leave a comment

Here are some EUC items I found interesting last week. For more immediate updates, follow me at http://twitter.com/cstalhood.

For a list of updates at carlstalhood.com, see the Detailed Change Log.

 

XenApp/XenDesktop

App Layering (Unidesk)

HDX

WEM/Profile Management

StoreFront

Receiver

NetScaler

NetScaler Gateway

XenMobile

Global Server Load Balancing (GSLB) – Citrix ADC

Last Modified: Mar 30, 2023 @ 10:18 am

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GSLB Planning

GSLB is nothing more than DNS. GSLB receives a DNS query, and then GSLB sends back an IP address, which is exactly how a DNS server works. The user then connects to the returned IP, which doesn’t even need to be on a NetScaler ADC.

GSLB can do some things that DNS servers can’t do:

  • Don’t give out an IP address unless it is UP (monitoring)
    • If the active IP address is down, then give out the passive IP address (active/passive) instead
  • Give out the IP address that is closest to the user (proximity load balancing)
  • Give out different IPs for internal users vs external users (DNS View)

GSLB is only useful if you have a single DNS name that could resolve to two or more IP addresses. If there’s only one IP address, then use normal DNS instead.

Citrix Blog Post Global Server Load Balancing: Part 1 explains how DNS queries work and how GSLB fits in.

Citrix has a good DNS and GSLB Primer.

When configuring GSLB, don’t forget to ask “where is the data?”. See Citrix Blog Post XenDesktop, GSLB & DR – Everything you think you know is probably wrong!

GSLB Configuration Overview

GSLB Configuration can be split between one-time steps for GSLB infrastructure, and repeatable steps for each GSLB-enabled DNS name.

One-time GSLB Infrastructure configuration

  1. Create ADNS listener on each ADC pair – DNS clients send DNS queries to the ADNS listeners. GSLB resolves a DNS query into an IP address, and returns the IP address in the DNS response.
  2. Create GSLB Sites (aka MEP Listener) – GSLB Sites usually correspond to different datacenters. GSLB Sites are also the IP address endpoints for Citrix ADC’s proprietary Metric Exchange Protocol (MEP), which is used by GSLB to transmit proximity, persistence, and monitoring information.
  3. Import Static Proximity Database – Citrix ADC includes a database that can be used to determine the geographical location of an IP address. Or you can subscribe to a geolocation service, and import its database.
  4. Delegate DNS sub-zone to ADC ADNS – in the original DNS zone, create a new sub-zone (e.g. gslb.company.com), and delegate the sub-zone to all ADNS listeners.

Repeatable GSLB Configuration for each DNS name:

  1. Create one or more GSLB Services per DNS name, and per IP address response – each GSLB Service corresponds to a single IP address that can be returned in response to a DNS Query.
    • Optionally, bind a Monitor to each GSLB Service. Monitors determine if the GSLB Service is up or not.
  2. Create a GSLB Virtual Server per DNS name
    • Bind a DNS name to the GSLB Virtual Server.
    • For active/active – bind multiple GSLB Services to the GSLB Virtual Server, configure a load balancing method (e.g. proximity), and configure site persistence.
    • For active/passive – bind the active GSLB Service. Create another GSLB Virtual Server with passive GSLB Service and configure as Backup Virtual Server.
      • Alternatively, NetScaler ADC 13.1 and newer let you bind GSLB Services in priority order. See Citrix Docs for details.
  3. Create CNAME records for each delegated DNS name – in the main DNS zone, create a CNAME that maps the original DNS name to the delegated sub-zone. For example, CNAME citrix.company.com to citrix.gslb.company.com.

You will create separate GSLB Services, separate GSLB Virtual Servers, and separate CNAMEs for each DNS name. If you have a bunch of DNS names that you want to GSLB-enable, then you’ll repeat these steps for each GSLB-enabled DNS name.

Each datacenter has a separate ADNS listener IP address. DNS is delegated to all GSLB ADNS Listener IPs, and any one of them can respond to the DNS query. Thus, all ADC pairs participating in GSLB should have the same Per-DNS name configuration.

One ADC appliance for both public DNS/GSLB and internal DNS/GSLB?

GSLB can be enabled both publically and internally. For public GSLB, configure it on DMZ ADC appliances, and expose the DNS listener to the Internet. For internal GSLB, configure it on separate internal ADC appliances/instances, and create an internal DNS listener.

Each ADC appliance only has one DNS table, so if you try to use the same ADC for both public DNS and internal DNS, then be aware that external users can query for internal GSLB-enabled DNS names.

  • As described by Phil Bossman in the comments, you can use a Responder policy to prevent external users from reading internal DNS names. 
    add policy patset GSLB_INTERNAL
bind policy patset GSLB_INTERNAL internalHostname.gslb.domain.com -index 1
add responder action DNS_Empty_Response respondwith DNS.NEW_RESPONSE
add responder policy GSLB_DNS_Empty_Response "(!(CLIENT.IP.SRC.IN_SUBNET(10.0.0.0/8)||CLIENT.IP.SRC.IN_SUBNET(192.0.0.0/16)||CLIENT.IP.SRC.IN_SUBNET(172.0.0.0/12)) && DNS.REQ.QUESTION.DOMAIN.CONTAINS_ANY(\"GSLB_INTERNAL\"))" DNS_Empty_Response
bind responder global GSLB_DNS_Empty_Response 100 END -type DNS_REQ_DEFAULT

One appliance resolving a single DNS name differently for internal and public

Let’s say you have a single DNS name citrix.company.com. When somebody external resolves the name, it should resolve to a public IP. When somebody internal resolves the name, it should resolve to an internal IP.

For internal GSLB and external GSLB of the same DNS name on the same ADC appliance, you can use DNS Policies and DNS Views to return different IP addresses depending on where users are connecting from. See Citrix CTX130163 How to Configure a GSLB Setup for Internal and External Users Using the Same Host Name.

If the Internet circuit in the remote datacenter goes down, then this should affect public DNS, since you don’t want to give out a public IP that isn’t reachable. But do you also want an Internet outage to affect internal DNS? Probably not. In that case, you would need different GSLB monitoring configurations for internal DNS and external DNS. However, if you have only a single GSLB Virtual Server with DNS Views, then you can’t configure different monitoring configurations for each DNS View.

To work around this limitation, create two separate GSLB Virtual Servers with different monitoring configurations. Internal DNS uses a CNAME record to reach the GSLB Virtual Server configured for internal monitoring:

  • External citrix.company.com:
    • Configure ADC GSLB for citrix.company.com.
    • On public DNS, delegate citrix.company.com to the ADC DMZ ADNS services.
  • Internal citrix.company.com:
    • Configure ADC GSLB for citrixinternal.company.com or something like that.
    • On internal DNS, create CNAME for citrix.company.com to citrixinternal.company.com
    • On internal DNS, delegate citrixinternal.company.com to ADC internal ADNS services.

Remote Internet Monitoring

For public DNS/GSLB, you don’t want to give out a remote public IP address if that remote public IP address is not reachable. That means the local ADC will need to somehow determine if the remote datacenter has Internet connectivity or not. Here are some methods of verifying the remote Internet connection:

  • Route GSLB Metric Exchange Protocol (MEP) across the Internet. If MEP goes down, then all IP addresses associated with the remote GSLB Site are assumed to be down, and thus the local ADC will stop giving out those remote IP addresses.
  • Bind explicit monitors to each GSLB Service, and ensure the monitoring is routed across the Internet.

GSLB IP Addresses

GSLB is separate from data traffic. The GSLB IP addresses are separate from the IP addresses needed for data.

Some GSLB-specific IP Addresses are needed on each ADC pair:

  • ADNS Listener IP: An ADC IP that listens for DNS queries.
    • The ADNS listener IP is typically an existing SNIP on the appliance.
    • For external DNS, create a public IP for the ADNS Listener IP, and open UDP 53 and TCP 53, so Internet-based DNS servers can access it.
    • A single ADC appliance can have multiple ADNS listeners – typically one ADNS listener for public, and another ADNS listener for internal.
  • GSLB Site IP / MEP listener IP: An ADC IP that will be used for ADC-to-ADC GSLB communication. This communication is called MEP or Metric Exchange Protocol. MEP transmits the following between GSLB-enabled ADC pairs: load balancing metrics, proximity, persistence, and monitoring.
    • GSLB Sites – On ADC, you create GSLB Sites. GSLB Sites are the endpoints for the MEP communication. Each ADC pair is configured with the MEP endpoints for the local appliance pair, and all remote appliance pairs.
    • TCP Ports – MEP uses port TCP 3009 or TCP 3011 between the ADC pairs. TCP 3009 is encrypted.
    • The ADNS IP address can be used as the MEP endpoint IP.
    • MEP endpoint can be any IP – The MEP endpoint IP address can be any IP address and does not need to be a SNIP or ADNS.
    • One MEP IP per appliance – there can only be one MEP endpoint IP address on each ADC pair.
    • Route MEP across Internet? – If you route MEP across the Internet, and if the MEP connection is interrupted, then Internet at one of the locations is probably not working. This is an easy way to determine if remote Internet is up or not. If you don’t route MEP across the Internet, then you’ll need to configure every remote-site GSLB Service with a monitor to ensure that the remote Internet is up.
      • Public IPs for MEP Enpoints – if you route MEP across the Internet, then you’ll need public IPs for each publically-accessible MEP endpoint IP address.
      • Public Port for MEP: Open port TCP 3009 between the MEP Public IPs. Make sure only the MEP IPs can access this port on the other ADC . Do not allow any other device on the Internet to access this port. Port 3009 is encrypted.
    • GSLB Sync Ports: To use GSLB Configuration Sync, open ports TCP 22 and TCP 3008 (secure) from the NSIP (management IP) to the remote public MEP IP. The GSLB Sync command runs a script in BSD shell and thus NSIP is always the Source IP.
  • Public IP Summary: In summary, for public GSLB, if MEP and ADNS are listening on the same IP, then you need one new public IP that is NAT’d to the DMZ IP that is used for ADNS and MEP (GSLB Site IP).
    • Each datacenter has a separate public IP.
    • DNS is delegated to all public ADNS IP listeners.

GSLB Wizard

NetScaler 12 and Citrix ADC 12.1 and newer have a GSLB Wizard at Traffic Management > GSLB.

However, the wizard doesn’t really save any time or steps, so it won’t be documented here.

ADNS Listener

  1. At System > Network > IPs, identify a Citrix ADC-owned IP that you will use as the ADNS listener. This is typically a SNIP.
  2. Create a public IP for the ADNS Service IP and configure firewall rules. UDP 53 and TCP 53 need to be opened from the Internet to the public IP that NATs to the ADNS Listener IP address.
  3. On the left, expand Traffic Management > Load Balancing, and click Services.
  4. On the right, click Add.

    1. In the Basic Settings section, do the following:
      1. Name the service ADNS or similar.
      2. In the IP Address field, enter an appliance SNIP.
      3. In the Protocol drop-down, select ADNS.
    2. Click OK.
    3. No other configuration is needed so scroll down and click Done to close the Load Balancing Service properties.
  5. Highlight the ADNS service you just added and then click Add to create another Service while copying some of the settings from the previously created Service.

    1. Change the Service Name to ADNS_TCP or similar.
    2. Change the Protocol drop-down to ADNS_TCP.
    3. Click OK to close the Basic Settings section.
    4. No other configuration is needed so scroll down and click Done to close the Load Balancing Service properties.
  6. You should have two ADNS services on the same IP address: one for ADNS, and one for ADNS_TCP.
  7. On the left of the console in the menu, expand System, expand Network, and then click IPs.
  8. On the right, you’ll see the SNIP is now marked as the ADNS svc IP.
  9. Repeat the ADNS configuration on the other appliance pair in the other datacenter. Except the other appliance will use its own SNIP as the ADNS Service listener IP address.
  10. Your ADC appliances are now DNS servers.

DNS Security

  1. Citrix ADC includes DNS Security Options, at Security > DNS Security, which can protect your ADNS service.
  2. To protect ADNS, set the Profile to All DNS Endpoints.

Metric Exchange Protocol

This section details MEP configuration between two GSLB Sites. See Citrix Docs for larger Parent-Child Topology Deployment Using the MEP Protocol.

GSLB Sites

  1. The local GSLB Site IP can be any IP, including the same SNIP that you used for ADNS.
  2. Open the firewall rules for Metric Exchange Protocol. The GSLB Site IP on this appliance pair uses TCP 3009 to communicate with the GSLB Site IP on the other appliance pair.
  3. On the left, expand Traffic Management, right-click GSLB, and enable the feature.
  4. Expand GSLB, and click Sites.
  5. On the right, click Add.
  6. In the Create GSLB Site page, do the following:
    1. We’re adding the local site first. Enter a descriptive name for the local site.
    2. In the Site Type drop-down, select LOCAL.
    3. In the Site IP Address field, enter an IP that this appliance will listen for MEP traffic. This is typically a SNIP and can the same as your ADNS IP.
    4. For Internet-routed GSLB MEP, in the Public IP Address field, enter the public IP that is NAT’d to the GSLB Site IP.
    5. For internal GSLB MEP, there is no need to enter anything in the Public IP field.
  7. Scroll down, and click Create, to close the Create GSLB Site page.

  8. Go back to System > Network > IPs, and notice that the IP is now marked as a GSLB site IP.
  9. If you want to use the GSLB Sync Config feature, then you’ll need to edit the GSLB site IP, and enable Management Access.

    1. Scroll down, and enable Management Access. SSH is all you need.
  10. Go to the other appliance pair, and also create the Local GSLB site using its GSLB site IP, and its public IP that is NAT’d to the GSLB site IP.

    1. In System > Network > IPs on the remote appliance, there should now be a GSLB site IP. If GSLB Sync is desired, enable management access on that IP and ensure SSH is enabled.
  11. Now on each appliance, add another GSLB Site, which will be the Remote GSLB site.
  12. In the Create GSLB Site page, do the following:
    1. Enter a descriptive name for the remote site.
    2. Select REMOTE as the Type.
    3. Enter the other appliance’s actual GSLB Site IP as configured on the appliance. This IP does not need to be reachable.
    4. In the Public IP Address field, enter the public IP that is NAT’d to the GSLB Site IP on the other appliance. For MEP, TCP 3009 must be open from the local GSLB Site IP, to the remote public Site IP. For GSLB sync, TCP 22, and TCP 3008, must be open from the local NSIP, to the remote public Site IP.
  13. Click Create.
  14. Repeat on the other appliance.

RPC

MEP defaults to unencrypted on TCP 3011. To fix that:

  1. On the left, expand System, expand Network, and click RPC.
  2. On the right, right-click the new RPC address (the other site’s GSLB Site IP), and click Edit.
  3. On the bottom, check the box next to Secure. In ADC 13.0 64.x and 12.1 build 61.x onwards, Secure is enabled by default. (source = Citrix CTX292743 Configuration Sync, Propagation and MEP Propagation Might Fail After Upgrade to 13.0 64.x\12.1 61.x)

    • If your local GSLB Site IP is not a SNIP, then you’ll need to change the RPC Node to use the local GSLB Site IP as the source IP. In the Source IP Address field, enter the local GSLB Site IP.
  4. Click OK when done.
  5. Do the same thing on the other appliance.
  6. If you go back to GSLB > Sites, you should see it as active.

See Citrix Tech Zone Troubleshooting Citrix GSLB MEP Cheat Sheet

If your MEP connection between GSLB Sites flaps, it might be useful to introduce a delay before remote GSLB Services are marked as Down.

  1. You can do this at Traffic Management > GSLB > Dashboard.
  2. On the right, click Change GSLB settings.
  3. In the GSLB Service State Delay Time (secs) field, enter a delay before the GSLB Services are marked as down when MEP goes down.

    set gslb parameter -GSLBSvcStateDelayTime 15

Static Proximity Geo Location Database

If you want to use DNS Policies, or Static Proximity GSLB Load Balancing, or Responders based on user’s location, import a geo location database.

Citrix ADC has a built-in database at /var/netscaler/inbuilt_db/ that you can use. Or you can download a database. Common free databases are:

For IP2Location, see the blog post Add IP2Location Database as NetScaler’s Location File for instructions on how to import.

CTX235799 NetScaler data formats for Location Database Import

Citrix Github has a Citrix-ADC-GSLB-GeoIP-Conversion-Tool that can convert Maxmind GeoIP City database to Citrix ADC (NetScaler) format.

Import the Built-in Geo database:

  1. In the Citrix ADC GUI, on the left, expand Traffic Management, expand GSLB, expand Database and Entries, and click Static Databases.
  2. On the right, click Add.
  3. Change the Import From selection to File.
  4. Click Choose File.
  5. Browse to /var/netscaler/inbuilt_db/. To browse to the directory, select var, and then click Open.
  6. Repeat for each directory until you reach /var/netscaler/inbuilt_db.
  7. In ADC 12.1, you can select the file named Citrix_Netscaler_InBuild_GeoIP_DB_IPv4. In NetScaler 12.0, select the only file shown. Then click Open.
  8. In the Location Format field, if using the built-in database, select netscaler, and click Create.
  9. After you later create a GSLB Service, when you open the GSLB Service, the public IP will be translated to a location based on the contents of the static proximity database.

Private IP Blocks

Geo Location databases only contain entries for Public IPs. For Private IPs, do the following:

  1. On the left, expand Traffic Management, expand GSLB, expand Database and Entries, and click Custom Entries.
  2. On the right, click Add.
  3. Enter a range of IP addresses for a particular location.
  4. Enter a Location Name in Geo Location format, which is typically six location words separated by periods. You can look in the static proximity database for examples.
  5. Make sure you enter coordinates. Google can find you coordinates for cities.
  6. Click Create.
  7. Continue creating Custom Entries for other private IP blocks.

Use Geo Locations

You can use the Geo locations in a DNS Policy, static proximity GSLB Load Balancing, Responders, and Rewrites:

Prior to Citrix ADC 12.1 build 50, the only option in policy expressions is to match a known location.

Citrix ADC 12.1 build 50 and newer lets you extract the user’s location and use it in policy expressions.

GSLB Services

GSLB Services represent the IP addresses that are returned in DNS Responses. The IP addresses represented by GSLB Services do not need to be hosted on a Citrix ADC, but Citrix ADC-owned IP addresses (e.g. load balancing VIPs) have additional GSLB Site Persistence options (e.g. cookie-based persistence).

  • Each potential IP address in a DNS response is a separate GSLB Service.
  • GSLB Services are associated with GSLB Sites.
  • GSLB Service configuration is identical for active/active and active/passive. GSLB Virtual Server configuration defines active/active or active/passive, not GSLB Services.

GSLB should be configured identically on all Citrix ADC pairs that are responding to DNS queries. Since you have no control over which Citrix ADC will receive the DNS query, you must ensure that both Citrix ADC pairs are giving out the same DNS responses.

To create a GSLB Service:

  1. On the left, expand Traffic Management > GSLB, and click Services.
  2. On the right, click Add.
  3. The service name should be similar to the DNS name that you are trying to GSLB. Include the site name in the service name.
  4. Select one of the GSLB Sites. The IP address you’re configuring in this GSLB Service should be geographically located in the selected GSLB Site.
  5. On the bottom part, if the IP address is owned by this Citrix ADC, then select Virtual Servers, and select a Virtual Server that is already defined on this appliance. It should automatically fill in the other fields. This option is only available when creating a GSLB Service in the Local GSLB Site.

    1. If the IP address is not owned by this Citrix ADC, then change the selection to New Server, and enter the remote IP address in the Server IP field.
    2. The Server IP field is the IP address that Citrix ADC will monitor for reachability.
    3. If the remote IP is owned by a different Citrix ADC that is reachable by MEP, then enter the actual VIP configured on that remote Citrix ADC. The Server IP does not need to match what is returned to the DNS Query.
  6. In the Public IP field, enter the IP address that will be returned to the DNS Query. If you leave Public IP blank, then Citrix ADC will copy the Server IP to the Public IP field. For Public GSLB, the Public IP field is usually a Public IP address. For internal GSLB, the Public IP field is usually an internal IP, and probably matches the Server IP.
  7. Scroll up, and make sure the Service Type is SSL. It’s annoying that Citrix ADC doesn’t set this drop-down correctly.
  8. Scroll down, and click OK, to close the Basic Settings section.
  9. GSLB Service Monitoring – on the right, in the Advanced Settings column, you can click Monitors to bind a monitor to this GSLB Service. Review the following notes before you bind a monitor.

    • Local Citrix ADC VIP – If the GSLB Service IP is a VIP on the local appliance, then GSLB will simply use the state of the local traffic Virtual Server (Load Balancing, Content Switching, or Gateway). There’s no need to bind a monitor to the GSLB Service.
    • Remote Citrix ADC VIP – If the GSLB Service IP is a VIP on a remote appliance, then GSLB will use MEP to ask the other appliance for the state of the remote traffic Virtual Server. In both cases. There’s no need to bind a monitor to the GSLB Service.
    • GSLB Monitor overrides other Monitoring methods – If you bind a monitor to the GSLB Service, then MEP and local Virtual Server state are ignored (overridden).
    • Here are some reasons for binding a monitor to the GSLB Service:
      • IP is not on a Citrix ADC– If the GSLB Service IP is not hosted on a Citrix ADC, then only a monitor can determine if the Service IP is up or not.
      • Monitor remote Internet – For Public DNS, if MEP is not routed through the Internet, then you need some method of determining if the remote Internet circuit is up or not. In that case, you’ll need to bind monitors directly to the GSLB Service. The route of the Monitor should go across the Internet. Or you can ping the Internet router in the remote datacenter to make sure it’s reachable.
      • Traffic Domains – If the GSLB Service IP is in a non-default Traffic Domain, then you will need to attach a monitor, since GSLB cannot determine the state of Virtual Servers in non-default Traffic Domains.
      • TCP monitor – for TCP services (not UDP), a simple TCP monitor is probably all you need. The TCP monitor tries to connect to the GSLB Service Public IP address using the SNIP of the local appliance. Make sure firewall on both sides allows this connection.
  10. Active/Active Site Persistence – If you intend to do GSLB active/active, and if you need site persistence, then on the right you can add Site Persistence and enable Connection Proxy or HTTP Redirect. See Citrix Blog Post Troubleshooting GSLB Persistence with Fiddler for more details. This only works with GSLB Service IPs that match Virtual Server VIPs on Citrix ADC appliances reachable through MEP.

  11. Scroll down, and click Done, to finish creating the GSLB Service.
  12. Create additional GSLB Services for each IP address that will be returned to a DNS query. There should be at least two for each DNS name.
  13. When creating a GSLB Service, select the correct Site, and make sure Service Type = SSL.
  14. The State will probably be down until the other ADC is configured.

Manually Synchronize GSLB Configuration

Copy the GSLB Service Configuration to the remote Citrix ADC pair. You can either repeat the GUI steps listed above. Or you can do the following:

  1. On the left, expand Traffic Management, expand GSLB, and click Dashboard.
  2. On the right, click View GSLB Configuration.
  3. This shows you all of the CLI commands for GSLB. Look for add gslb service commands. You can copy them, and run them (SSH) on other Citrix ADC pairs that are participating in GSLB.

GSLB Virtual Server

GSLB Virtual Server is the entity that links a DNS name with GSLB Services.

For Active/Passive GSLB in NetScaler ADC 13.1 or newer, GSLB Services can be bound in priority order. GSLB will give out the IP address of the lowest order GSLB Service. If that GSLB Service is down, then GSLB will give out the IP address of the next order GSLB Service.

  1. Create a GSLB Virtual Server.
  2. Bind the active GSLB Service but set the Order to 1.
  3. Bind the passive GSLB Service but set the Order to 2.
  4. Bind a DNS name to the GSLB Virtual Server.
  5. Repeat the GSLB Virtual Server configuration on other Citrix ADC pairs participating in GSLB.
  6. Delegate the DNS name to Citrix ADC ADNS.

For Active/Passive GSLB, the Active GSLB Virtual Server will give out a single IP address if that IP address up. If the GSLB Service is down, then it will fail over to a Backup GSLB Virtual Server that gives out a different IP address.

  1. Create a GSLB Virtual Server for the Passive IP address.
    1. Bind the Passive GSLB Service to the Passive GSLB Virtual Server.
  2. Create another GSLB Virtual Server for the Active IP address.
    1. Bind the Active GSLB Service to the Active GSLB Virtual Server.
    2. Configure Backup Virtual Server pointing to the Passive GSLB Virtual Server.
    3. Bind a DNS name to the Active GSLB Virtual Server.
  3. Repeat the GSLB Virtual Server configuration on other Citrix ADC pairs participating in GSLB.
  4. Delegate the DNS name to Citrix ADC ADNS.

For Active/Active GSLB, a single GSLB Virtual Server gives out multiple IP addresses based on load balancing method and site persistence.

  1. Create one GSLB Virtual Server.
    1. Bind two or more GSLB Services to the Virtual Server.
    2. Configure the GSLB Virtual Server Load Balancing Method – e.g., Proximity
    3. Configure Site Persistence:
      1. Source IP persistence is configured on the GSLB Virtual Server.
      2. Cookie Persistence is configured on the GSLB Services.
    4. Bind a DNS name to the GSLB Virtual Server.
  2. Repeat the GSLB Virtual Server configuration on other Citrix ADC pairs participating in GSLB.
  3. Delegate the DNS name to Citrix ADC ADNS.

Configure Active/Passive GSLB in NetScaler ADC 13.1 and newer

  1. On the left, expand Traffic Management, expand GSLB, and click Virtual Servers.
  2. On the right, click Add.
  3. In the Basic Settings section, do the following:
    1. Give the GSLB Virtual Server a descriptive name.
    2. Set the Service Type to SSL to match the GSLB Sevices you intend to bind.

      add gslb vserver <gslb_vserver_name> SSL
  4. Click OK to close the Basic Settings section.
  5. On the left, click where it says No GSLB Virtual Server to GSLB Service Binding.

    1. Click where it says Click to select.
    2. Check the box next to the active GSLB Service and click Select.
    3. In the Order box, enter 1. Click Bind.
  6. To add another GSLB Service Binding, on the left, click where it says 1 GSLB Virtual Server to GSLB Service Binding.

    1. Click Add Binding.
    2. Click where it says Click to select.
    3. Check the box next to a passive GSLB Service and then click Select at the top of the page.
    4. In the Order box, enter 2 so that this GSLB Service is only used if all Order 1 GSLB Services are down. Click Bind.
  7. Click OK to close the GSLB Services and GSLB Service Group Binding section.
  8. On the left, click where it says No GSLB Virtual Server Domain Binding.

    1. Enter the FQDN that this GSLB Virtual Server will resolve.
    2. Click Bind.
    3. If you are doing CNAME (e.g., citrix.corp.com CNAME to citrix.gslb.corp.com, then add domain bindings for both the main FQDN and the CNAME FQDN. Click Close when done.
  9. Click OK to close the GSLB Virtual Server Domain Binding section.
  10. Click OK to close the ADNS Service section.
  11. With GSLB Services assigned to different Order numbers, it is not necessary to configure Backup Virtual Server.
  12. If you bound multiple GSLB Services to a single Order number, then you might want to adjust Method and Persistence.
  13. Click Done to finish creating the GSLB Virtual Server.
  14. On the left, if you expand Traffic Management > DNS, expand Records, and click Address Records…
  15. You’ll see a new DNS record for the GSLB domain you just configured. Notice it is marked as GSLB DOMAIN, and has a default TTL of 5 seconds. You can also see which GSLB Virtual Server it is bound to.
  16. Configure an identical GSLB Virtual Server on the other NetScaler ADC appliance pair. Both NetScaler ADC pairs must be configured identically. You can use Traffic Management > GSLB > Dashboard > View GSLB Configuration to copy the add/set/bind gslb vserver commands from this appliance to other NetScaler ADC appliances.


Configure Active/Passive GSLB in NetScaler ADC 13.0 and older

Passive Virtual Server

  1. On the left, expand Traffic Management, expand GSLB, and click Virtual Servers.
  2. On the right, click Add.
  3. In the Basic Settings section, do the following:
    1. Give the Passive GSLB Virtual Server a descriptive name.
    2. Set the Service Type to SSL to match the GSLB Services that you will bind to this Virtual Server.
  4. Click OK to close the Basic Settings section.
  5. On the left, click where it says No GSLB Virtual Server to GSLB Service Binding.

    1. Click where it says Click to select.
    2. Check the box next to an existing Passive GSLB Service, and then click the blue Select button at the top of the screen.
    3. Click Bind.
  6. Click OK to close the GSLB Virtual Server GSLB Service Binding section.
  7. Click OK to close the GSLB Virtual Server Domain Binding section. The DNS name is bound to the Active Virtual Server, not the Passive Virtual Sever.
  8. Click OK to close the ADNS Service section.
  9. Click Done to finish creating the Passive GSLB Virtual Server.

Active Virtual Server

  1. On the left, expand Traffic Management, expand GSLB, and click Virtual Servers.
  2. On the right, click Add.
  3. In the Basic Settings section, do the following:
    1. Give the Active GSLB Virtual Server a descriptive name.
    2. Set the Service Type to SSL to match the GSLB Services that you will bind to this Virtual Server.
  4. Click OK to close the Basic Settings section.
  5. On the left, click where it says No GSLB Virtual Server to GSLB Service Binding.

    1. Click where it says Click to select.
    2. Check the box next to an existing Active GSLB Service, and click Select.
    3. Click Bind.
  6. Click OK to close the GSLB Virtual Server GSLB Service Binding section.
  7. On the left, click where it says No GSLB Virtual Server Domain Binding.
  8. In the Domain Binding page, do the following:
    1. Enter the FQDN that GSLB will resolve.
    2. Click Bind.
  9. Click OK to close the GSLB Virtual Server Domain Binding section.
  10. Click OK to close the ADNS Service section.
  11. On the right, in the Advanced Settings section, click Backup Virtual Server to add it to the left.
  12. On the left, in the Backup Virtual Server section, select the Passive GSLB Virtual Server, and click OK.
  13. Click Done when done creating the Active GSLB Virtual Server.
  14. On the left, if you expand Traffic Management > DNS, expand Records, and click Address Records…
  15. On the right, you’ll see a new DNS record for the GSLB domain you just configured. Notice the Type is GSLB DOMAIN, and has a default TTL of 5 seconds. You can also see which GSLB Virtual Server it is bound to.
  16. Configure identical GSLB Virtual Servers on the other Citrix ADC appliance pair. Both Citrix ADC pairs must be configured identically. You can use Traffic Management > GSLB > Dashboard > View GSLB Configuration to copy the add/set/bind gslb vserver commands from this appliance to other Citrix ADC appliances.

Configure Active/Active GSLB

  1. On the left, expand Traffic Management, expand GSLB, and click Virtual Servers.
  2. On the right, click Add.
  3. In the Basic Settings section, do the following:
    1. Give the GSLB Virtual Server a descriptive name.
    2. Set the Service Type to SSL to match the GSLB Sevices you intend to bind.
    3. You can optionally check the box for Send all “active” service IPs in response (MIR). By default, GSLB only gives out one IP address per DNS query. This checkbox always returns all IPs, but the IPs are ordered based on the GSLB Load Balancing Method and/or GSLB Persistence.
    4. A new DNS feature called ECS will contain the actual DNS client IP. This dramatically improves the accuracy of determining a user’s location. Without this setting, GSLB can only see the IP address of the user’s configured DNS server instead of the real client IP. Check the box next to Respond with ECS option to enable ECS for site persistence.

      set gslb vserver <gslb_vserver> -ECS ENABLED
  4. Click OK to close the Basic Settings section.
  5. On the left, click where it says No GSLB Virtual Server to GSLB Service Binding.

    1. Click where it says Click to select.
    2. Check the boxes next to multiple existing GSLB Services, and click Select.
    3. Click Bind.
  6. Click OK to close the GSLB Virtual Server GSLB Service Binding section.
  7. On the left, click where it says No GSLB Virtual Server Domain Binding.

    1. Enter the FQDN that this GSLB Virtual Server will resolve.
    2. Click Bind.
  8. Click OK to close the GSLB Virtual Server Domain Binding section.
  9. Click OK to close the ADNS Service section.
  10. On the left, in the Method section, click the pencil icon.

    1. For poximity load balancing, change the Choose Method drop-down to RTT with STATICPROXIMITY as backup.
      1. RTT = Round Trip Time. Each ADC appliance sends a ping to the user’s DNS server. Whichever ADC appliance gets the fastest response determines the site of the GSLB Service. RTT requires that ADC be able to ping anything on the Internet so adjust firewall rules accordingly.
      2. STATICPROXIMITY requires that the Geo Location database has already been installed on the appliance.
    2. Click OK to close the Method section.
  11. On the right, in the Advanced Settings column, click Persistence to add it to the left.

    1. On the left, at the bottom of the page in the Persistence section, change the Persistence drop-down to Source IP.
    2. Enter a Persistence Id.
      1. The Persistence ID signifies the persistence table that each ADC pair shares across the MEP connection.
      2. Each active/active GSLB Virtual Server should have a different Persistence ID (different persistence table).
      3. When you configure the same GSLB Virtual Server on each Citrix ADC pair, specify the same Persistence ID so every Citrix ADC has the same persistence information for this particular GSLB Virtual Server.
    3. In the Time-out field, enter the Persistence Time-out. This is typically the same or longer than the webpage timeout.
    4. Click OK to close the Persistence section.
  12. Click Done to finish creating the GSLB Virtual Server.
  13. On the left, if you expand Traffic Management > DNS, expand Records, and click Address Records…
  14. You’ll see a new DNS record for the GSLB domain you just configured. Notice it is marked as GSLB DOMAIN, and has a default TTL of 5 seconds. You can also see which GSLB Virtual Server it is bound to.
  15. Configure an identical GSLB Virtual Server on the other Citrix ADC appliance pair. Both Citrix ADC pairs must be configured identically. You can use Traffic Management > GSLB > Dashboard > View GSLB Configuration to copy the add/set/bind gslb vserver commands from this appliance to other Citrix ADC appliances.


GSLB Configuration Synchronization Script

Manual GSLB Synchronization

  1. The synchronization script requires SSH to be enabled on your GSLB Site IPs.

  2. Ports TCP 3008, TCP 3010, and TCP 22 must be opened from the local NSIP to the remote GSLB Site IP. The source IP is NSIP, not SNIP.
  3. To manually run the script that syncs GSLB configuration from one GSLB Site to another, on the left, expand Traffic Management, expand GSLB, and click Dashboard.
  4. On the right, click the button labelled Auto Synchronization GSLB.
  5. Use the check boxes on the top, if desired. It’s usually a good idea to Preview the changes before applying them.
  6. Then click Run to begin synchronization.
  7. Click Close.
  8. You can Run it again without previewing it. It seems to take several seconds to complete.

Automatic GSLB Synchronization

  1. There is an automatic GSLB Configuration Sync feature, which automatically syncs the GSLB config every 15 seconds. To enable it on the master appliance, go to Traffic Management > GSLB > Dashboard. On the right, click Change GSLB settings.
  2. Check the box next to Automatic Config Sync. Only enable this on the one appliance where you are configuring GSLB, and want that GSLB config synced to other appliance.
  3. The automatic sync log can be found at /var/netscaler/gslb/periodic_sync.log.

Some notes regarding GSLB Sync:

  • When syncing GSLB Services, it tries to create Load Balancing Server objects on the remote appliance. If the GSLB Service IP matches an existing Load Balancing Server object, then the GSLB sync will fail. Check the Sync logs for details. You’ll have to delete the conflicting Load Balancing Server object before GSLB Sync works correctly.
  • GSLB Sync runs as a script on the BSD shell and thus always uses the NSIP as the source IP.
  • GSLB Sync connects to the remote GSLB Site IP on TCP 3008 (if RPC is Secure) and TCP 22.

Test GSLB

  1. You can test GSLB DNS name resolution from the GUI by going to Traffic Management > GSLB > Dashboard, and on the right, click the button labelled Test GSLB.

  2. Select a GSLB Domain Name.
  3. Select an ADNS Service IP to test it from, and click Test.
  4. The test performs a dig against the ADNS IP. Verify that the response contains the IP address you expected.
  5. Another method of testing GSLB is to simply point nslookup to the ADNS services and submit a DNS query for one of the DNS names bound to a GSLB vServer. Run the query multiple times to make sure you’re getting the response you expect.
    • The syntax is “nslookup <DNS_name> <ADNS_IP>”. The second argument specifies the DNS server that you send the DNS Query to.
  6. The Citrix ADC ADNS services at both GSLB sites should be giving the same response.
  7. To simulate a failure, if the GSLB Service IP is a Citrix ADC Load Balancing, Content Switching, or Citrix Gateway IP, you can disable the Virtual Server.
  8. Then the responses should change. Verify on both ADNS services.
  9. Re-enable the Virtual Server, and the responses should return to normal.

DNS Delegation

If you are enabling GSLB for the domain gateway.corp.com, you’ll need to create a delegation at the server that is hosting the corp.com DNS zone. For public GSLB, you need to edit the public DNS zone for corp.com.

DNS Delegation instructions will vary depending on what product is hosting the public DNS zone. This section details Microsoft DNS, but it should be similar in BIND or web-based DNS products.

There are two ways to delegate GSLB-enabled DNS names to Citrix ADC ADNS:

  • Delegate the individual record –  For example, delegate gateway.corp.com.
  • Delegate an entire subzone – For example, delegate the subzone gslb.corp.com. Then create a CNAME record in the parent DNS zone for gateway.corp.com that is aliased to gateway.gslb.corp.com. For additional delegations, simply create more CNAME records.
    • The incoming DNS query to the ADNS listener is for gateway.gslb.corp.com and not gateway.corp.com. You’ll need to bind gateway.gslb.corp.com to your GSLB Virtual Server. You can bind multiple FQDNs to a single GSLB Virtual Server.

A delegation consists of the following DNS records:

  • A records (host records) that resolve to each Citrix ADC ADNS IP address. If you have two ADC pairs participating in GSLB, then you’ll need one A record for each ADC pair.
    • The A record names are typically something like ns1.corp.com and ns2.corp.com, just like you would name any other DNS server.
    • You only create the A records once. The A records for ADNS services can be used by multiple delegations.
    • These A records for ADNS are sometimes called glue records.
  • NS records for each delegation. The NS records point to the A records that resolve to the ADC ADNS IP addresses. If you have two ADC ADNS IP addresses, then you need two NS records for each delegation.
    • When delegating individual records, you create separate NS records for each delegation. If you have two ADNS listeners, then you need two NS records for each delegation.
    • When delegating a subzone, you only need NS records for the subzone. To GSLB-enable a DNS name, you create a CNAME that aliases to a record under the subzone.

Delegate an individual DNS record

  1. Run DNS Manager.
  2. First, create Host Records pointing to the ADNS services running on the Citrix ADC pairs in each data center. These host records for ADNS are used for all GSLB delegations no matter how many GSLB delegations you need to create. These are sometimes called glue records.
  3. The first Host record is gslb1, (or similar) and should point to the ADNS service (Public IP) on one of the Citrix ADC appliances.
  4. The second Host record is gslb2, and should point to the ADNS Service (public IP) on the other Citrix ADC appliance.
  5. If you currently have a host record for the service that you are delegating to GSLB (e.g. gateway.corp.com), delete it.
  6. Right-click the parent DNS zone, and click New Delegation.
  7. In the Welcome to the New Delegation Wizard page, click Next.
  8. In the Delegated Domain Name page, enter the left part of the DNS record that you are delegating (e.g. gateway for gateway.corp.com). Click Next.
  9. In the Name Servers page, click Add.
  10. This is where you specify gslb1.corp.com and gslb2.corp.com as delegated name servers. Enter gslb1.corp.com, and click Resolve. Then click OK. If you see a message about the server not being authoritative for the zone, ignore the message. Note: you only add one name server at a time.
  11. Then click Add to add the other GSLB ADNS server.
  12. Once both ADNS servers are added to the list, click Next.
  13. In the Completing the New Delegation Wizard page, click Finish.
  14. The delegation is shown in the DNS Manager console.
  15. For proper delegation, the Name Server records should also be added to Citrix ADC. (source = Citrix CTX241493 Citrix Response on DNS Flag Day)
    1. On the GSLB Citrix ADC appliances, expand Traffic Management, expand DNS, expand Records, and click Name Server Records.
    2. On the right, click Add.
    3. In the Domain Name field, enter the name of the delegated DNS name (e.g. gateway.corp.com).
    4. In the Name Server field, leave it set to –<< New >>–, and enter one of the FQDNs for your GSLB ADNS services. This is one of the glue records you created earlier.
    5. Click Create.
    6. Add another Name Server Record for the same domain name. But this time, enter the second GSLB ADNS FQDN. Repeat this process until all GSLB ADNS FQDNs are specified.

  16. Also add an SOA record for the delegation. If you are delegating individual records, then you will need an SOA for each record. If you are delegating a subzone, you only need an SOA record for the subzone.
    1. On the left, in the menu, go to Traffic Management > DNS > Records > SOA Records.
    2. On the right, click Add.
    3. In the Domain Name field, enter the FQDN that you delegated to NetScaler. This can be an individual record, or a sub-zone.
    4. In the Origin Server field, leave it set to –<< New >> — and then enter the FQDN that resolves to one of your ADNS listeners. It doesn’t matter which one you enter.
    5. In the Contact field, enter an email address that is publicly viewable. Replace the @ symbol with a period.
    6. Click Create.
    7. Repeat this on the other ADCs that are participating in GSLB for this delegated DNS name.
  17. If you run nslookup against your Microsoft DNS server, it will respond with Non-authoritative answer. That’s because it got the response from Citrix ADC, and not from the original DNS server that you send the request to.

Delegate a Sub-zone

  1. Run DNS Manager.
  2. First, create Host Records pointing to the ADNS services running on the Citrix ADC pairs in each data center. These are sometimes called glue records.

    1. The first Host record is gslb1 (or similar), and should point to the ADNS service (Public IP) on one of the Citrix ADC appliances.
    2. The second Host record is gslb2, and should point to the ADNS Service (public IP) on the other Citrix ADC appliance.
  3. Right-click the parent DNS zone, and click New Delegation.
  4. In the Welcome to the New Delegation Wizard page, click Next.
  5. In the Delegated Domain Name page, enter the left part of the DNS sub-zone that you are delegating (e.g. gslb for gslb.corp.com). Click Next.
  6. In the Name Servers page, click Add.
  7. This is where you specify gslb1.corp.com and gslb2.corp.com. Enter gslb1.corp.com, and click Resolve. Then click OK. If you see a message about the server not being authoritative for the zone, ignore the message. Note: you only add one name server at a time.
  8. Then click Add to add the other GSLB ADNS server.
  9. Once both ADNS servers are added to the list, click Next.
  10. In the Completing the New Delegation Wizard page, click Finish.
  11. The sub-zone delegation is shown in the DNS Manager console.
  12. For proper delegation, the Name Server records should also be added to Citrix ADC. (source = Citrix CTX241493 Citrix Response on DNS Flag Day)
    1. On the GSLB Citrix ADC appliances, expand Traffic Management, expand DNS, expand Records, and click Name Server Records.
    2. On the right, click Add.
    3. In the Domain Name field, enter the name of the delegated sub-domain (e.g. gslb.corp.com).
    4. In the Name Server field, leave it set to –<< New >>–, and enter one of the FQDNs for your GSLB ADNS services. This is one of the glue records you created earlier.
    5. Click Create.
    6. Add another Name Server Record for the same domain name. But this time, enter the second GSLB ADNS FQDN.

    7. Repeat this process until all GSLB ADNS FQDNs are specified.
  13. Also add an SOA record for the delegation. If you are delegating individual records, then you will need an SOA for each record. If you are delegating a subzone, you only need an SOA record for the subzone.
    1. On the left, in the menu, go to Traffic Management > DNS > Records > SOA Records.
    2. On the right, click Add.
    3. In the Domain Name field, enter the FQDN that you delegated to NetScaler. This can be an individual record, or a sub-zone.
    4. In the Origin Server field, leave it set to –<< New >> — and then enter the FQDN that resolves to one of your ADNS listeners. It doesn’t matter which one you enter.
    5. In the Contact field, enter an email address that is publicly viewable. Replace the @ symbol with a period.
    6. Click Create.
    7. Repeat this on the other ADCs that are participating in GSLB for this delegated DNS name.

Each GSLB-enabled DNS name must be CNAME’d to GSLB:

  1. In Citrix ADC, go to Traffic Management > GSLB > Virtual Servers, and edit your GSLB Virtual Server.
  2. On the left, click in the GSLB Virtual Server Domain Binding section.
  3. Click Add Binding.
  4. Add a domain binding for the CNAME’d DNS name. For example, if the original DNS name is gateway.corp.com, then enter gateway.gslb.corp.com. gslb.corp.com matches the sub-zone that you delegated to Citrix ADC. Click OK.
  5. Repeat the Domain Binding on the other Citrix ADC appliances.
  6. In DNS Manager, if you currently have a host record for the service that you are delegating to GSLB (gateway.corp.com), delete it.
  7. Right-click the DNS zone, and click New Alias (CNAME).
  8. In the Alias name field, enter the left part of the original DNS name. For gateway.corp.com, enter gateway.
  9. In the Fully qualified domain name (FQDN) for target host field, enter the CNAME’d DNS name that is delegated to Citrix ADC. For example, if you delegated gslb.corp.com to Citrix ADC, then enter gateway.gslb.corp.com. The GSLB Virtual Server must be configured to match this longer DNS name.
  10. Click OK.
  11. If you run nslookup for the delegated DNS name, it will first CNAME to the longer name, and then respond with the IP address returned by Citrix ADC GSLB.
  12. You can repeat these steps to delegate (CNAME) additional DNS names to Citrix ADC GSLB.

RADIUS Authentication – Citrix Gateway

Last Modified: Mar 29, 2021 @ 11:28 am

215 Comments

This article applies to Citrix Gateway 13.0, Citrix Gateway 12.1, and NetScaler Gateway 12.0. Citrix ADC is the new name for NetScaler. Citrix Gateway is the new name for NetScaler Gateway.

Navigation

Change Log

RADIUS Overview

One method of two-factor authentication to Citrix Gateway is the RADIUS protocol with a two-factor authentication product (tokens) that has RADIUS enabled.

  • Another common two-factor authentication method is SAML to an Identity Provider, like Azure Active Directory or Okta. SAML is detailed in the Federated Authentication Service article.

RADIUS Clients and Source IP – On your RADIUS servers, you’ll need to add the ADC appliances as RADIUS Clients. When ADC uses a local (same appliance) load balanced Virtual Server for RADIUS authentication, the traffic is sourced from the ADC SNIP (Subnet IP). When ADC uses a direct connection to a RADIUS Server without going through a load balancing Virtual Server, or uses a remote (different appliance) Load Balancing Virtual Server, the traffic is sourced from the ADC NSIP (ADC Management IP). Use the correct IP(s) when adding the ADC appliances as RADIUS Clients. And adjust firewall rules accordingly.

  • For High Availability pairs, if you locally load balance RADIUS, then you only need to add the SNIP as a RADIUS Client, since the SNIP floats between the two appliances. However, if you are not locally load balancing RADIUS, then you’ll need to add the NSIP of both appliances as RADIUS Clients. Use the same RADIUS Secret for both appliances.

Links:

Some two-factor products (e.g. SMS Passcode) require you to hide the 2nd password field. Receiver 4.4 and newer supports hiding the 2nd field if you configure a Meta tag in index.html.

Two-factor Policies Summary

ADC has two methods of configuring multi-factor authentication:

  • Citrix Gateway Virtual Server has bind points for Primary and Secondary authentication. This functionality is available in all ADC Editions and is detailed in this post.
    • This is the older method of configuring authentication also known as Classic authentication policies. One challenge with Classic policies is that Citrix Workspace app requires the LDAP and RADIUS fields to be swapped.
  • nFactor Authentication supports unlimited factors, but requires ADC Advanced Edition (formerly known as Enterprise Edition) or ADC Platinum Edition.
    • nFactor is the newer authentication configuration method also known as Advanced authentication policies. With nFactor, there’s no need to swap the LDAP and RADIUS fields for Citrix Workspace app.

Workspace app authentication with a Classic Policy configuration looks like a Window that is very difficult to customize.

Workspace app authentication with an nFactor configuration looks like a webpage that is fully customizable.

See the ADC menu page for additional authentication mechanisms supported by Citrix Gateway. Some require nFactor.

When configuring the Citrix Gateway Virtual Server, you can specify both a Primary authentication policy, and a Secondary authentication policy. Users are required to successfully authenticate against both policies before being authorized for Citrix Gateway.

For browser-based StoreFront, you need two authentication policies:

  • Primary = LDAPS authentication policy pointing to Active Directory Domain Controllers.
  • Secondary = RADIUS authentication policy pointing to RSA servers with RADIUS enabled.

For Citrix Workspace app, the classic authentication policies need to be swapped. There’s no need to swap them if doing nFactor (Advanced) policies.

  • Primary = RADIUS authentication policy pointing to RSA servers with RADIUS enabled.
  • Secondary = LDAPS authentication policy pointing to Active Directory Domain Controllers.

With Classic Authentication Policies, if you need to support two-factor authentication from both web browsers and Citrix Workspace app, then you’ll need at least four authentication policies as shown below.

Primary:

  • Priority 90 = RADIUS policy. Expression = REQ.HTTP..HEADER User-Agent CONTAINS CitrixReceiver
  • Priority 100 = LDAP policy. Expression = REQ.HTTP..HEADER User-Agent NOTCONTAINS CitrixReceiver

Secondary:

  • Priority 90 = LDAP policy. Expression = REQ.HTTP..HEADER User-Agent CONTAINS CitrixReceiver
  • Priority 100 = RADIUS policy. Expression = REQ.HTTP..HEADER User-Agent NOTCONTAINS CitrixReceiver

LDAP Server/Action

See the LDAP post for instructions to create an LDAP Server/Action. Only the LDAP server/action is needed. The Policies will be created later.

RADIUS Server/Action

Create a RADIUS Server/Action:

  1. On the left, expand Authentication, and click Dashboard.
  2. On the right, click Add.
  3. Change Choose Server Type to RADIUS.
  4. Give the server a name.
  5. Specify the IP address of the RADIUS load balancing Virtual Server.
  6. Enter the secret key specified when you added the ADCs as RADIUS clients on the RADIUS server. Click Test RADIUS Reachability.
  7. Scroll down, and click More.
  8. Find the Password Encoding drop-down. Change it to mschapv2 if your RADIUS server supports it, c. Microsoft NPS requires mschapv2 to support changing expired Active Directory passwords. 💡
  9. If you want ADC to receive AAA Group information from RADIUS, see CTX222260 Radius Group Extraction from Windows Server 2008/2012 with NetScaler/CloudBridge.
    • RADIUS attribute = 26 (Vendor-Specific)
    • Vendor Code = 3845 (Citrix)
    • Vendor-assigned attribute number = any number (e.g. 1). Configure RADIUS policy on ADC with same attribute number.
    • Attribute value = Group Name
  10. Click Create.

    add authentication radiusAction RSA -serverIP 10.2.2.210 -serverPort 1812 -authTimeout 60 -radKey Passw0rd -passEncoding mschapv2

Advanced Authentication (nFactor) Policies for LDAP and RADIUS

For the older Classic Authentication policies, jump ahead to the Classic Policies section.

Create Advanced Authentication Policies:

  1. In the left menu, go to Security > AAA – Application Traffic > Policies > Authentication > Advanced Policies > Policy.
  2. On the right, click Add.
  3. In the Create Authentication Policy window:
    1. Change the Action Type to RADIUS.
    2. Select your RADIUS Action.
    3. Give the policy a name.
    4. Expression = true.
  4. Click Create.
  5. Create another Authentication Policy.
    1. Set Action Type to LDAP.
    2. Select your LDAP Action/Server.
    3. Give the policy a name.
    4. Expression = true.
  6. Click Create.

Create a Policy Label for the second factor, which is typically the RADIUS policy. The first factor (LDAP) does not need a Policy Label.

  1. In the left menu, click Policy Label.
  2. On the right, click Add.
  3. Give the Policy Label a name.
  4. Leave Login Schema set to LSCHEMA_INT. The Login Schema in the first factor will collect both password and passcode in one form so there’s no need for the second factor to collect it again.
  5. Click Continue.
  6. In the Select Policy field, select your RADIUS policy.
  7. Click Bind at the bottom of the page.
  8. Click Done to finish creating the Policy Label.

Create a Login Schema to collect the password and passcode on the same form.

  1. In the left menu, click Login Schema.
  2. On the right, switch to the tab named Profiles and then click Add.
  3. Give the Login Schema a name (e.g. DualAuth).
  4. Click the pencil icon and then open the LoginSchema folder.
  5. Click the DualAuth.xml file on the left. On the right, make sure you click the blue Select button. It’s too easy to miss this step.
    • See my nFactor article for some info on how to customize the Login Schema.
  6. Then click Create.
  7. On the right, switch to the tab named Policies.
  8. Give the Login Schema Policy a name.
  9. Select the Login Schema Profile you just created.
  10. Set the Rule field to true.
  11. Click Create.

Create an Authentication (AAA) Virtual Server to link the factors together.

  1. In the left menu, under AAA – Application Traffic, click Virtual Servers.
  2. On the right, click Add.
  3. Change the IP Address Type to Non Addressable.
  4. Give the AAA vServer a name and then click OK.
  5. In the Certificate section, you can optionally bind a certificate. It doesn’t matter what certificate you choose (typically the Gateway cert). The only thing this certificate binding does is make the AAA vServer show as UP instead of DOWN. Otherwise it has no effect on functionality. Click Continue.
  6. In the Advanced Authentication Policies section, click where it says No Authentication Policy.
  7. In the Select Policy field at the top of the window, select the LDAP policy.
  8. Near the bottom, in the Select Next Factor field, click where it says Click to select.
  9. Select your RADIUS Policy Label and then click Bind. After LDAP is done, nFactor will then move to your RADIUS Policy Label.
  10. Click Continue.
  11. On the right, in the Advanced Settings column, click Login Schemas.
  12. On the bottom left, click where it says No Login Schema.
  13. Select the DualAuth Login Schema you created earlier and then click Bind.
  14. Click Done at the bottom of the page.

Link the AAA vServer to your Gateway vServer:

  1. In the left menu, expand Citrix Gateway and then click Virtual Servers.
  2. On the right, edit your Gateway vServer.
  3. On the right, in the Advanced Settings column, click Authentication Profile.
  4. On the bottom left, in the Authentication Profile section, click the Add button.
  5. Select the AAA vServer you created earlier.
  6. Give the Profile a name and then click Create.
  7. Back in the Gateway vServer, make sure you click OK in the Authentication Profile section. If you forget to click OK then the Authentication Profile won’t be bound.

If you point your Workspace app to the Gateway that has nFactor configured, the authentication window will look like a web page.

Classic Authentication Policies for LDAP and RADIUS

For Advanced Authentication (nFactor) policies, jump back to the Advanced Policies section.

  1. Go to Citrix Gateway > Policies > Authentication > RADIUS.
  2. On the right, in the Policies tab, click Add.
  3. In the Create Authentication RADIUS Policy page:
    1. Name the policy RSA-ReceiverSelfService or similar.
    2. Select the RADIUS server created earlier.
    3. Enter an expression. You will need two policies with different expressions. The expression for Receiver Self-Service is REQ.HTTP.HEADER User-Agent CONTAINS CitrixReceiver.
      Note: Citrix Gateway 12.1 does not natively support binding of Advanced Authentication Policies so you’ll have to create them as Basic Policies (classic expressions). You can only bind Advanced Authentication Policies using nFactor.
  4. Click Create.
  5. If you see a warning about deprecation, click OK, and ignore it.
  6. Create another RADIUS policy to match the ones shown below. Both RADIUS policies are configured with the same RADIUS server. The only difference between them is the expression (CONTAINS vs NOTCONTAINS):
    Name Expression Server
    RSA-ReceiverSelfService REQ.HTTP.HEADER User-Agent CONTAINS CitrixReceiver RSA
    RSA-ReceiverForWeb REQ.HTTP.HEADER User-Agent NOTCONTAINS CitrixReceiver RSA

  7. Go to the Citrix Gateway\Policies\Authentication\LDAP node.
  8. On the Policies tab, create two policies with the expressions shown below. Both LDAP policies are configured with the same LDAP server. The only difference between them is the expression (CONTAINS vs NOTCONTAINS).
    Name Expression Server
    LDAP-Corp-ReceiverSelfService REQ.HTTP.HEADER User-Agent CONTAINS CitrixReceiver LDAP-Corp
    LDAP-Corp-ReceiverForWeb REQ.HTTP.HEADER User-Agent NOTCONTAINS CitrixReceiver LDAP-Corp 

add authentication radiusPolicy RSA-ReceiverForWeb "REQ.HTTP.HEADER User-Agent NOTCONTAINS CitrixReceiver" RSA

add authentication radiusPolicy RSA-ReceiverSelfService "REQ.HTTP.HEADER User-Agent CONTAINS CitrixReceiver" RSA

add authentication ldapPolicy Corp-Gateway-ReceiverForWeb "REQ.HTTP.HEADER User-Agent NOTCONTAINS CitrixReceiver" Corp-Gateway

add authentication ldapPolicy Corp-Gateway-ReceiverSelfService "REQ.HTTP.HEADER User-Agent CONTAINS CitrixReceiver" Corp-Gateway

Bind Two-factor Policies to Gateway

  1. When you create or edit a Citrix Gateway Virtual Server, bind the Basic Authentication Policies as shown in the following table. Priority doesn’t matter because they are mutually exclusive.
    Policy Name Type Bind Point
    LDAP-Corp-ReceiverForWeb LDAP Primary
    RSA-ReceiverSelfService RADIUS Primary
    LDAP-Corp-ReceiverSelfService LDAP Secondary
    RSA-ReceiverForWeb RADIUS Secondary 

    bind vpn vserver gateway.corp.com -policy Corp-Gateway-ReceiverForWeb -priority 100

bind vpn vserver gateway.corp.com -policy RSA-ReceiverSelfService -priority 110

bind vpn vserver gateway.corp.com -policy RSA-ReceiverForWeb -priority 100 -secondary

bind vpn vserver gateway.corp.com -policy Corp-Gateway-ReceiverSelfService -priority 110 -secondary
  2. The Session Policy/Profile for Receiver Self-Service needs to be adjusted to indicate which authentication field contains the Active Directory password. On the Client Experience tab is Credential Index. This needs to be changed to SECONDARY. Leave the session policy for Web Browsers set to Primary.

    set vpn sessionAction "Receiver Self-Service" -ssoCredential SECONDARY
  3. On the StoreFront server, when creating the Citrix Gateway object, on the Authentication Settings page, change the Logon type to Domain and security token. This instructs Receiver / Workspace app to properly handle two-factor authentication. If you change this setting after Receiver / Workspace app has already performed discovery, then users might have to remove the Account from Receiver / Workspace app and re-add it.

RADIUS Load Balancing – NetScaler 12

Last Modified: Apr 1, 2020 @ 6:41 am

32 Comments

Navigation

Change Log

  • 2018 Feb 17 – in RADIUS Monitor section, added Microsoft Network Policy Server Ping User-Name. (Source = Stefano Losego in the comments)
  • 2017 Dec 25 – updated entire article for 12.0 build 56. Monitor section has new build 56 instructions.

RADIUS Load Balancing Overview

One method of two-factor authentication to NetScaler Gateway is the RADIUS protocol with a two-factor authentication product (tokens) that has RADIUS enabled.

RADIUS Clients and Source IP – On your RADIUS servers, you’ll need to add the NetScaler appliances as RADIUS Clients. When NetScaler uses a local (same appliance) load balanced Virtual Server for RADIUS authentication, the traffic is sourced from the NetScaler SNIP (Subnet IP). When NetScaler uses a direct connection to a RADIUS Server without going through a load balancing Virtual Server, or uses a remote (different appliance) Load Balancing Virtual Server, the traffic is sourced from the NetScaler NSIP (NetScaler IP). Use the correct IP(s) when adding the NetScaler appliances as RADIUS Clients. And adjust firewall rules accordingly.

  • For High Availability pairs, if you locally load balance RADIUS, then you only need to add the SNIP as a RADIUS Client, since the SNIP floats between the two appliances. However, if you are not locally load balancing RADIUS, then you’ll need to add the NSIP of both appliances as RADIUS Clients. Use the same RADIUS Secret for both appliances.

RADIUS Monitor and Static Credentials – When load balancing RADIUS, you’ll want a monitor that verifies that the RADIUS server is functional. The RADIUS monitor will login to the RADIUS server and look for a response. The credentials in the load balancing monitor must have a static password.

  • If you don’t mind failed login attempts in your RADIUS logs, you can specify fake credentials in your load balancing monitor. The monitor would be configured to expect a login failure response, which means that at least a RADIUS service is responding to the monitor. Not as accurate as a successful login response, but better than ping.
  • The only other monitoring option is Ping. No credentials needed for this option. Adjust the firewall to allow ping to the RADIUS servers.

Active/passive load balancing – If you have RADIUS Servers in multiple datacenters, you can create multiple load balancing Virtual Servers, and cascade them so that the local RADIUS Servers are used first, and if they’re not available, then the Virtual Server fails over to RADIUS Servers in remote datacenters.

RADIUS Monitor

The RADIUS Monitor attempts to successfully log into the RADIUS server. For RSA, create an account on RSA with the following parameters as mentioned by Jonathan Pitre:

  • Setup a user with a fixed passcode in your RSA console.
  • Ensure you login with that user at least once to the RSA console because you’ll be asked to change it the first time.
  • There is no need to assign a token to your monitor user as long as you are using a fixed passcode. You don’t want to waste a token on a user just for monitoring.

Henny Louwers – Configure RSA RADIUS monitoring on NetScaler.

12.0 build 56 and newer

Monitor instructions changed in 12.0 build 56 and newer. If your build is older than build 56, then jump to the older Monitor instructions.

  1. In the NetScaler Configuration Utility, on the left, under Traffic Management > Load Balancing, click Monitors.
  2. On the right, click Add.
  3. Name the monitor RSA or similar.
  4. In the Type field, click where it says Click to select.
  5. Scroll down and click the circle next to RADIUS.
  6. Scroll up and click the blue Select button.
  7. In the Basic Parameters section, you might have to increase the Response Time-out to 4.
  8. In the Basic Parameters section, do the following:
    1. Enter valid RADIUS credentials. Make sure these credentials do not change or expire. For RSA, in the Password field, enter the fixed passcode.
    2. Enter the RADIUS key (secret) configured on the RADIUS server for the NetScaler as RADIUS client.
    3. For Response Codes, add both 2 and 3. 2 means success, while 3 indicates some kind of failure. Either result means that the RADIUS server is responding, and thus is probably functional. But 2 is the ideal response.
  9. Scroll down and click Create.

    add lb monitor RSA RADIUS -respCode 2-3 -userName ctxsvc -password Passw0rd -radKey Passw0rd -resptimeout 4
  10. Jump to the Servers section.

12.0 older than build 56

  1. In the NetScaler Configuration Utility, on the left, under Traffic Management > Load Balancing, click Monitors.
  2. On the right, click Add.
  3. Name the monitor RSA or similar.
  4. Change the Type drop-down to RADIUS.
  5. On the Standard Parameters tab, you might have to increase the Response Time-out to 4.
  6. On the Special Parameters tab, do the following:
    1. Enter valid RADIUS credentials. Make sure these credentials do not change or expire. For RSA, in the Password field, enter the fixed passcode.
    2. Also enter the RADIUS key (secret) configured on the RADIUS server for the NetScaler as RADIUS client.
    3. For Response Codes, add both 2 and 3. 2 means success, while 3 indicates some kind of failure. Either result means that the RADIUS server is responding, and thus is probably functional. But 2 is the ideal response.
  7. Click Create when done.

    add lb monitor RSA RADIUS -respCode 2-3 -userName ctxsvc -password Passw0rd -radKey Passw0rd -resptimeout 4

Servers

  1. On the left, expand Traffic Management, expand Load Balancing, and click Servers.
  2. On the right, click Add.
  3. Enter a descriptive server name; usually it matches the actual server name.
  4. Enter the IP address of the RADIUS server.
  5. Enter comments to describe the server. Click Create.

    add server RSA01 10.2.2.42
add server RSA02 10.2.2.43
  6. Continue adding RADIUS servers.

Service Groups

  1. On the left, expand Traffic Management, expand Load Balancing, and click Service Groups.
  2. On the right, click Add.
  3. You will create one Service Group per datacenter. Enter a name reflecting the name of the datacenter.
  4. Change the Protocol to RADIUS.
  5. Scroll down, and click OK, to close the Basic Settings section.
  6. On the left, in the Service Group Members section, click where it says No Service Group Member.

    1. If you did not create server objects, then enter the IP address of a RADIUS Server in this datacenter. If you previously created a server object, then change the selection to Server Based, and select the server object(s).
    2. In the Port field, enter 1812 (RADIUS).
    3. Click Create.
  7. Click OK when done adding members.
  8. On the right, in the Advanced Settings column, click Monitors.

    1. On the left, in the Monitors section, click where it says No Service Group to Monitor Binding.
    2. In the Select Monitor field, click where it says Click to select.
    3. Click the circle next to your new RADIUS monitor. It might be on page 2.
      • You must click the circle exactly (no room for error). If you click outside the circle, then the monitor will be opened for editing. If this happens, click Close to return to the selection screen.
    4. At the top of the window, click the blue Select button.
    5. Click Bind.
  9. To verify the members are up, click in the Service Group Members section.

    1. Right-click a member, and click Monitor Details.
    2. It should say Radius response code 2 (or 3) received. Click Close twice.
  10. Scroll down, and click Done to finish creating the Service Group.

    add serviceGroup svcgrp-RSA RADIUS
bind serviceGroup svcgrp-RSA RSA01 1812
bind serviceGroup svcgrp-RSA RSA02 1812
bind serviceGroup svcgrp-RSA -monitorName RSA
  11. Add additional service groups for RADIUS servers in each data center.

Virtual Server

  1. On the left, expand Traffic Management, expand Load Balancing, and click Virtual Servers.
  2. On the right, click Add.
  3. In the Basic Settings section, do the following:
    1. Name it lbvip-RADIUS-HQ or similar. You will create one Virtual Server per datacenter so include the datacenter name.
    2. Change the Protocol drop-down to RADIUS.
    3. Enter a Virtual IP. This VIP cannot conflict with any other IP + Port already being used. You can use an existing VIP if the VIP is not already listening on UDP 1812.
    4. Enter 1812 as the Port.
  4. Click OK to close the Basic Settings section.
  5. In the Services and Service Groups section, click where it says No Load Balancing Virtual Server ServiceGroup Binding.

    1. Click where it says Click to select.
    2. Click the circle next to a previously created Service Group. It might be on Page 2.
      • You must click the circle exactly (no room for error). If you click outside the circle, then the Service Group will be opened for editing. If this happens, click the x on the top right, or click Done on the bottom, to return to the selection screen.
    3. At the top of the window, click the blue Select button.
    4. Click Bind.
  6. Click Continue.
  7. On the right, in the Advanced Settings section, click Method.
  8. On the left, in the Method section, do the following:
    1. Change the Load Balancing Method to TOKEN.
    2. In the Expression box, enter CLIENT.UDP.RADIUS.USERNAME.
  9. Click OK to close the Method section.
  10. On the right, in the Advanced Settings section, click Persistence.
  11. On the left, in the Persistence section, do the following:
    1. Change Persistence to RULE. Note: 12.0 build 56 and newer is slightly different than older builds.
    2. In the Expression box, enter CLIENT.UDP.RADIUS.USERNAME.
  12. Click OK to close the Persistence section.
  13. Scroll down and click Done to finish creating the Virtual Server.
  14. If you are configuring this RADIUS Load Balancer for more than just NetScaler Gateway, you can add another Load Balancer on port 1813 for RADIUS Accounting. Then you need a Persistency Group to tie the two load balancers together. See Configuring RADIUS Load Balancing with Persistence at Citrix Docs. 
    add lb vserver lbvip-RSA RADIUS 10.2.2.210 1812 -persistenceType RULE -lbMethod TOKEN -rule CLIENT.UDP.RADIUS.USERNAME
bind lb vserver lbvip-RSA svcgrp-RSA
  15. The new Virtual Server should show as Up. If not, click the Refresh icon on the top right of the screen (not the browser refresh).

Active/Passive Load Balancing

  1. Create additional Virtual Servers for each datacenter.

    1. These additional Virtual Servers do not need a VIP. so change the IP Address Type to Non Addressable. Only the first Virtual Server will be directly accessible.

      add lb vserver lbvip-RSA-Backup RADIUS 0.0.0.0 0 -persistenceType NONE -cltTimeout 120
    2. Notice that the additional datacenter Virtual Servers have an IP Address of 0.0.0.0 and port of 0.
  2. After you are done creating a Virtual Server for each datacenter, right-click the primary datacenter’s Virtual Server, and click Edit.
  3. On the right, in the Advanced Settings column, click Protection.
  4. On the left, in the Protection section, change the Backup Virtual Server to one of the other datacenter Virtual Servers. If all of the services in this datacenter are DOWN, the backup Virtual Server will be used instead. You can cascade multiple Virtual Servers using this method. Click OK and Done.

    set lb vserver lbvip-RSA -backupVServer lbvip-RSA-Backup
  5. You may now use this Virtual IP in your RADIUS authentication policies for NetScaler Gateway or NetScaler management login.

CLI Commands

Here is a list of CLI Commands for RADIUS load balancing.

# Load Balancing Global Parameters
# --------------------------------
enable ns mode FR L3 Edge USNIP PMTUD ULFD
set ns tcpParam -WS ENABLED -SACK ENABLED


# Monitors
# --------
add lb monitor RSA RADIUS -respCode 2-3 -userName rsamon -password Passw0rd -encrypted -encryptmethod ENCMTHD_3 -radKey Passw0rd -encrypted -encryptmethod ENCMTHD_3 -LRTM DISABLED -resptimeout 4


# Servers
# -------
add server RSA01 10.2.2.42

add server RSA02 10.2.2.43


# Service Groups
# --------------
add serviceGroup svcgrp-RSA-RADIUS-DR RADIUS -maxClient 0 -maxReq 0 -cip DISABLED -usip NO -useproxyport NO -cltTimeout 120 -svrTimeout 120 -CKA NO -TCPB NO -CMP NO
bind serviceGroup svcgrp-RSA-RADIUS-DR RSA01 1812
bind serviceGroup svcgrp-RSA-RADIUS-DR -monitorName RSA

add serviceGroup svcgrp-RSA-RADIUS-HQ RADIUS -maxClient 0 -maxReq 0 -cip DISABLED -usip NO -useproxyport NO -cltTimeout 120 -svrTimeout 120 -CKA NO -TCPB NO -CMP NO
bind serviceGroup svcgrp-RSA-RADIUS-HQ RSA02 1812
bind serviceGroup svcgrp-RSA-RADIUS-HQ -monitorName RSA


# Load Balancing Virtual Servers
# ------------------------------
add lb vserver lbvip-RADIUS-DR RADIUS 0.0.0.0 0 -persistenceType NONE -cltTimeout 120
bind lb vserver lbvip-RADIUS-DR svcgrp-RSA-RADIUS-DR

add lb vserver "lbvip-RADIUS HQ" RADIUS 10.2.5.70 1812 -persistenceType RULE -lbMethod TOKEN -rule CLIENT.UDP.RADIUS.USERNAME -cltTimeout 120 -backupVServer lbvip-RADIUS-DR
bind lb vserver "lbvip-RADIUS HQ" svcgrp-RSA-RADIUS-HQ

Citrix Gateway Tweaks

Last Modified: Jan 23, 2024 @ 3:58 pm

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Change Log

Citrix Gateway Feature Licensing

Here is a listing of some Citrix Gateway features and the licenses they require:

Feature ADC Editions Universal Licenses?
StoreFront Load Balancing Standard/Enterprise/Platinum  
Global Server Load Balancing (GSLB) Enterprise/Platinum  
ICA Proxy and StoreFront Proxy All  
Two-factor Auth (RADIUS) All  
StoreFrontAuth (nFactor) Enterprise/Platinum  
nFactor Authentication Enterprise/Platinum  
Native OTP Authentication (nFactor) Enterprise/Platinum  
Self-Service Password Reset (SSPR) Enterprise/Platinum  
HDX Insight (AppFlow) Enterprise/Platinum  
SmartAccess All Yes
SmartControl Platinum Yes
RDP Proxy Enterprise/Platinum Yes
SSL VPN All Yes
PCoIP Proxy Enterprise/Platinum Yes
Unified Gateway Enterprise/Platinum Yes
Citrix SCOM MP for NetScaler Platinum  

All Editions = Citrix Gateway VPX, NetScaler Standard Edition, NetScaler Advanced Edition (formerly known as Enterprise Edition), and NetScaler Premium Edition (formerly known as Platinum Edition).

  • Citrix Gateway VPX is the inexpensive VPX appliance that only does Citrix Gateway. It doesn’t even do Load Balancing. This edition is no longer sold by Citrix.
  • NetScaler Advanced Edition is the minimum edition for many Gateway features, and thus is recommended for all Gateway purchases.

Gateway Universal Licenses – many Citrix Gateway features require Citrix Gateway Universal licenses for each concurrent connection to the Citrix Gateway Virtual Server. See the above table for which features require these licenses.

When you create a Citrix Gateway Virtual Server, in the Basic Settings section, the ICA Only setting determines if you need Citrix Gateway Universal licenses or not. If the Virtual Server is set to ICA Only is true, then features requiring Universal Licenses are disabled. But if ICA Only is set to false, then you need a Citrix Gateway Universal license for every user that connects to this Citrix Gateway Virtual Server.

Most editions of NetScaler include Gateway Universal licenses:

  • Citrix Gateway VPX does not come with any Gateway Universal Licenses. This edition is no longer sold by Citrix.
  • NetScaler Standard Edition comes with 500 Gateway Universal Licenses. This edition is no longer sold by Citrix.
  • NetScaler Advanced Edition comes with 1,000 Gateway Universal Licenses
  • NetScaler Premium Edition comes with unlimited Gateway Universal Licenses

If your NetScaler Edition does not include a sufficient number of Universal Licenses for your user load, then you can acquire these licenses through other means:

  • Citrix Virtual Apps and Desktops (CVAD) Premium Edition includes Gateway Universal licenses for each licensed user
  • “a la carte” Citrix Gateway Universal Licenses – these are very inexpensive

You can install more Gateway Universal licenses on the NetScaler appliance. The Gateway Universal licenses are allocated to the case sensitive hostname of each appliance. If you have an HA pair, and if each node has a different hostname, then allocate the Gateway Universal licenses to the first hostname, and then reallocate the same licenses to the other hostname.

To see the hostname, click your username on the top right.

To change the hostname:

  1. Click the gear icon on the top right. Note: this icon won’t work unless you are logged in as nsroot.
  2. Then click the third section.

Go to https://citrix.com/account and allocate your purchased Gateway Universal licenses to the hostname of the appliance.

To upload the allocated Gateway Universal licenses to the appliance, go to System > Licenses > Manage Licenses. A reboot is required.

To see the number of installed Gateway Universal licenses:

  1. On the left, expand System, and click Licenses.
  2. On the right, in the Maximum Citrix Gateway Users Allowed field is the number of licensed users for Citrix Gateway Virtual Servers that are not set to ICA Only.

RfWebUI Portal Theme

Citrix Blog Post Branding your Deployment Part 2: Matching NetScaler to StoreFront explains Citrix Gateway Portal Themes, how to edit the Portal Theme CSS, and warns about GUI changes overwriting CSS file changes.

NetScaler article Unleashing RfWebUI Potential: JavaScript-Powered Citrix Gateway Login Page Customization explains how to use JavaScript to customize the RfWebUI theme.

NetScaler article Visually change RFWebUI with CSS shows how to relocate the form header to the top of the username input field and make it bold and adjust the positioning of the “User name:” and “Password:” labels nearer to the input fields.

If you want the logon page for Citrix Gateway to look like Citrix Cloud, then see CTX258331 Customizing the on-premises Citrix Gateway authentication page to look identical to Citrix Cloud logon page.

If you want the logon page for Citrix Gateway to look more like StoreFront 3.0 and newer, enable the built-in RfWebUI or X1 theme. RfWebUI is optimized for Unified Gateway (Clientless VPN) since it provides the exact same appearance and user experience as StoreFront 3.x. The Unified Gateway RfWebUI theme can display RDP Links, Web Links (bookmarks), PCoIP published icons, along with the familiar StoreFront apps and desktops. Note: RfWebUI requires StoreFront 3.6 or newer.

  1. Go to Citrix Gateway > Virtual Servers and edit an existing Virtual Server.
  2. If you see the Portal Theme section on the left:
    • Then click the pencil icon.
  3. If you don’t see Portal Theme on the left:
    • On the right, in the Advanced Settings section, click Portal Themes.
  4. On the left, change the Portal Theme drop-down to RfWebUI. Click OK.
  5. Click Done to close the Gateway Virtual Server. 
    bind vpn vserver gateway.corp.com -portaltheme RfWebUI
  6. When you access the Citrix Gateway login page you’ll see the theme.

RfWebUI Customizations

Custom Portal Theme

You can create your own theme by starting from one of the built-in themes:

  1. Go to Citrix Gateway > Portal Themes.
  2. On the right, click Add.
  3. Give the theme a name, select RfWebUI as the Template Theme, and click OK.
  4. In the Look and Feel section, there are two sub-sections: one for Home Page Attributes, and one for Common Attributes.
  5. The Home Page Attributes section is for Unified Gateway (aka VPN Clientless Access). Notice that the Websites Sections can be disabled.
  6. The Help Legend link at the top of the section shows you what the other fields modify.

  7. If you want to modify some attributes of the logon page, use the Common Attributes sub-section. The labels are changed later.
  8. The Help Legend link at the top of the Common Attributes section shows you what the fields modify.
  9. Make changes as desired, and click OK at the bottom of the page.
  10. After you click OK, the Language section appears.
  11. In the Language section, select a language, and click OK.
  12. On the right, in the Advanced Settings section, click Login Page.
  13. Make changes as desired (e.g. Password Field Titles), and click OK.
  14. At the top of the screen, click the link to Click to Bind and View Configured Theme.
  15. Select a Gateway Virtual Server, and click Bind and Preview. Notice that you can also bind Portal Themes to AAA vServers.
  16. The logon page is displayed.
  17. You could go to /var/netscaler/logon/themes/MyTheme/css and make more changes to custom.css, but this file gets overwritten any time you make a change in the Portal Themes section of the NetScaler GUI.
  18. Citrix CTX209526 NetScaler; How to Copy a Portal Theme from the Device running version 11.0 to another Device running 11.0.

Public DNS SRV Records

When a user launches Receiver, instead of typing in the Gateway FQDN, the user can enter an email address. Receiver uses the email suffix to lookup the Gateway FQDN. It does this by looking for an SRV record named _citrixreceiver._tcp in the email suffix’s domain (e.g. _citrixreceiver._tcp.corp.com). If you have multiple email suffixes, then you need to add the SRV record to each email suffix DNS zone.

Note: to eliminate certificate and/or trust prompts, the Gateway certificate must match discoverReceiver.email.suffix (e.g discoverReceiver.corp.com). If you have multiple email suffixes, then you need the certificate to match every email suffix.

To enable email-based discovery, add a SRV record to each public email suffix DNS zone. Here are sample instructions for a Windows DNS server:

  1. In Server Manager, click Tools > DNS.
  2. In the left pane of DNS Manager, right-click your DNS domain, and click Other New Records.
  3. In the Resource Record Type dialog box, select Service Location (SRV), and then click Create Record.
  4. In the New Resource Record dialog box, do the following:
    1. In the Service box, enter the host value _citrixreceiver.
    2. In the Protocol box, enter the value _tcp.
    3. In the Port number box, enter 443.
    4. In the Host offering this service box, specify the fully qualified domain name (FQDN) for your Citrix Gateway Virtual Server in the form servername.domain (e.g. gateway.company.com).
  5. Click OK to close the New Resource Record dialog box.
  6. Click Done to close the Resource Record Type dialog box.

Customize Logon Page

Logon Page Labels

When two factor authentication is configured on Citrix Gateway, the user is prompted for User name, Password, and Password 2.

The Password field labels can be changed to something more descriptive, such as Active Directory or RSA:

To change the labels, edit a Portal Theme:

  1. Go to Citrix Gateway > Portal Themes, and edit an existing theme. You can’t edit the built-in themes, so you’ll have to create one if you haven’t already.
  2. If you see the Login Page section on the left:
    • Click the pencil icon in the Login Page section.
  3. If you don’t see the Login Page section on the left:
    • On the right, in the Advanced Settings column, click Login Page to add it to the left.
  4. On the left, in the Login Page section, change the two Password fields to your desired text.
  5. Click OK to close the Login Page section.
  6. If you are using the RfWebUI theme, the default text size for the form field labels is 17px. However, the Portal Themes editor defaults to 12px. You can change it back to 16px or 18px by doing the following:
    1. In the Look and Feel section, click the pencil icon.
    2. Scroll down to the Common Attributes section.
    3. Change the Form Font Size drop-down to 16px or 18px.
    4. Click OK to close the Look and Feel section.
  7. In the Portal Theme section at the top of the page, you can Click to Bind and View Configured Theme to Preview your changes.
  8. You might have to invalidate the loginstaticobjects Integrated Caching Content Group (Optimization > Integrated Caching > Content Groups) before the changes appear. This seems to be true even if Integrated Caching is disabled.

 Logon Security Message (Disclaimer, EULA)

You can force users to agree to a EULA before they are allowed to login.

Clicking the Terms & Conditions link allows the user to view the EULA text that you have entered.

Do the following to configure the EULA:

  1. Go to Citrix Gateway > Resources > EULA.
  2. On the right, click Add.
  3. Give the EULA a name, and enter some text. You can even enter HTML code. See the example posted by Chris Doran at Citrix Discussions.
  4. Scroll down, and click Create.
  5. Edit a Gateway Virtual Server.
  6. On the right, in the Advanced Settings column, click EULA.
  7. On the left, in the EULA section, click where it says No EULA.
  8. Click where it says Click to select.
  9. Click the radio button next to the previously created EULA, and click Select.
  10. Click Bind.
  11. Mike Roselli at Automatic EULA Acceptance by Cookie Rewrite Guide at Citrix Discussions details Rewrite policies that change the behavior so that users only have to accept the EULA once. It records acceptance in a cookie.
  12. Sam Jacobs Adding an EULA for AAA Login at CUGC explains how to enable the EULA on the AAA logon page.

Theme File Customization

The original themes (Default, Green Bubble, and X1) use files from /netscaler/ns_gui/vpn/js and /var/netscaler/logon/themes. A commonly edited file is /netscaler/ns_gui/vpn/js/gateway_login_form_view.js since this file is responsible for rendering the logon form.

The new RfWebUI theme is different than the original themes, because it pulls files from /var/netscaler/logon/LogonPoint/receiver. This means the customizations for NetScaler 11.0 won’t work with the new RfWebUI theme. When reviewing customization guides for NetScaler 11, be aware that most of them won’t work for the RfWebUI theme.

Citrix CTX202444 How to Customize NetScaler Gateway 11 logon Page with Links shows how to add links to the Citrix Gateway 11 logon page. This only works in the Default, Green Bubble, and X1 themes (no RfWebUI theme).

Other Customizations

CTP Sam Jacobs at Adding Text, Links and Other Elements to the NetScaler Logon Page – Part 2 at CUGC explains how to add text to the RfWebUI theme logon page. The process for RfWebUI is quite different than the older themes:

  • Text is stored in /var/netscaler/logon/themes/<theme>/strings.<language code>.json
  • Custom CSS is stored in /var/netscaler/logon/themes/<theme>/css/theme.css
  • Sample Logon Page:

CTP Sam Jacobs at Adding Text, Links and Other Elements to the NetScaler Logon Page – Part 1 at CUGC explains how to modify custom.css and en.xml to add text below the logon box on the Logon Page. No Rewrite policies or source code modifications needed.

Mike Roselli at Netscaler 11 Theme Customization – How to Add Links and Verbiage at Citrix Discussions has sample rewrite policies to customize the Citrix Gateway logon page with additional HTML.

 

Craig Tolley Customising the NetScaler 11 User Interface – Adding Extra Content: add new sections to login page. These sections pull content from local HTML files.

 

Daniel Ruiz Set up a maintenance page on NetScaler Gateway: configure a Responder policy (see the blog post for sample HTML code). During maintenance, manually bind the Responder policy to the Gateway. Manually remove the policy after maintenance is complete.

 

Manuel Kolloff Adding additional languages to NetScaler RfWebUI Theme

 UDP Audio Through Gateway

From John Crawford at Citrix Discussions and Marius Sandbu Enabling Citrix Receiver audio over NetScaler Gateway with DTLS

Note: Enabling DTLS on the Gateway also enables the Gateway to support EDT (Adaptive Transport) and Framehawk.

Requirements for UDP Audio:

  • Citrix Receiver 4.2 or newer
  • UDP 443 allowed to Citrix Gateway Virtual Server
  • UDP 16500-16509 allowed from Citrix SNIP to the VDAs

To enable UDP Audio through Gateway, make changes on both the Citrix Gateway Virtual Server, and in Receiver:

  1. Edit a Citrix Gateway Virtual Server.
  2. In the Basic Settings section, click the pencil icon.
  3. Click More.
  4. Enable the DTLS option, and click OK.
  5. After enabling DTLS, it probably won’t work until you unbind the Gateway certificate, and rebind it.
    1. On the left, click where it says 1 Server Certificate.
    2. Click Add Binding.
    3. Click where it says Click to select.
    4. Click the radio button next to the same certificate that’s already bound. Click Select.
    5. Click Bind.
    6. Click Close.
    7. Click Continue to close the Certificate section.

Client-side configuration

There are two methods of enabling RTP on the client side:

  • Edit default.ica on the StoreFront server
  • Use GPO to modify the client-side config

To edit the default.ica file on the StoreFront server (h/t Vipin Borkar): Edit the file C:\inetpub\wwwroot\Citrix\Store\App_Data\default.ica and add the following lines to the Application section:

EnableRtpAudio=true
EnableUDPThroughGateway=true
AudioBandwidthLimit=1

To use GPO to modify the client-side config:

  1. Copy the receiver.admx (and .adml) policy template into PolicyDefinitions if you haven’t already.
  2. Edit a GPO that applies to Receiver machines. You can also edit the local GPO on a Receiver machine.
  3. Go to Computer Configuration | Policies | Administrative Templates | Citrix Components | Citrix Workspace app | User Experience.
  4. On the right, edit the setting Client audio settings.
  5. Do the following in the Client audio settings dialog box.
    1. Enable the setting.
    2. Set audio quality as desired. Higher quality = higher bandwidth.
    3. Check to Enable Real-Time Transport.
    4. Check to Allow Real-Time Transport through Gateway.
  6. Click OK to close the Client audio settings dialog box.
  7. Look in the client-side registry at HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Citrix\ICA Client\Engine\Lockdown Profiles\All Regions\Lockdown\Virtual Channels\Audio to make sure the registry keys applied.
  8. When you launch the first session after enabling Real-Time Transport, you might be prompted to enable it through the client-side firewall.

To view the current UDP Audio sessions:

  1. In the NetScaler GUI, click the Citrix Gateway node.
  2. On the right, click DTLS ICA Connections.
  3. This will show you all users that have UDP Audio connections through Citrix Gateway. Note: this is different than EDT. To see EDT (UDP) HDX connections, click ICA Connections instead.

Citrix VPN from Mobile Devices

Links:

Citrix VPN Clients on Mobile Devices (Android, iOS) contain one of the following in their User-Agent strings. You can use this text in a Session Policy expression.

  • CitrixReceiver/NSGiOSplugin
  • CitrixReceiver/CitrixVPN

To block the Citrix VPN client connections from mobile devices, do one of the following:

  • Create an AppExpert > Responder > Policy with Action = DROP and Expression = HTTP.REQ.HEADER("User-Agent").CONTAINS("CitrixReceiver/NSGiOSplugin")|| HTTP.REQ.HEADER("User-Agent").CONTAINS("CitrixReceiver/CitrixVPN"). Either bind the Responder Policy Globally, or bind it to the Gateway vServers.
  • In your Gateway Session Policies, on the Client Experience tab, set the Plug-in Type to Java. If any of them are set to Windows/MAC OS X, then VPN for Mobile is allowed.

StoreFront – Rewrite X-Citrix-Via

When Citrix Gateway communicates with StoreFront, it adds a header called X-Citrix-Via that contains the FQDN entered in the user’s address bar. StoreFront uses this header to find a matching Gateway object so StoreFront knows how to handle the authentication. In Citrix Gateway 11.0 and newer, you can create a rewrite policy to change this header. This is useful when changing URLs or using DNS aliases for Gateways. See CTX202442 FAQ: Modify HTTP Header X-Citrix-Via on NetScaler for more details.

Here’s a sample rewrite policy for this header:

enable ns feature REWRITE

add rewrite action rwact_storefront replace "HTTP.REQ.HEADER(\"X-Citrix-Via\")" "\"mystorefront.mydomain.com\""

add rewrite policy rwpol_storefront "HTTP.REQ.HEADER(\"X-Citrix-Via\").NE(\"mystorefront.mydomain.com\")" rwact_storefront

bind vpn vserver mygateway-vs -policy rwpol_storefront -priority 100 -type REQUEST

Device Certificates

Citrix Gateway can require Device Certificates (machine based) before a user can login. The Endpoint Analysis Plug-in reads the machine certificate, and compares it to a CA certificate that is bound to the Citrix Gateway Virtual Server.

  • Device Certificates are different from User Certificates.
  • Administrator permissions are required to access the machine certificate’s private key. Citrix Gateway Plug-in (VPN client) can workaround this requirement.
  • OCSP is required. You can use Microsoft Online Responder.

To enable Device Certificates on Citrix Gateway

  1. Create a OCSP Responder on NetScaler and bind it to the CA Certificate. See CTX200290 How to Configure Device Certificate on NetScaler Gateway for details. At Traffic Management > SSL > Certificates > OCSP Responder.

    1. The URL for Microsoft Online Responder is http://ocsp_server_FQDN:80/ocsp.
    2. Misja Geuskens at Netscaler Device certificate checks fails with W2K12R2 Online responder says don’t check the Nonce box.
  2. Import CA certificates for Root and Intermediate. At Traffic Management > SSL > Certificates > CA Certificates.
  3. Right-click each CA certificate, and click OCSP Bindings.

    1. Select the OCSP Responder you created earlier.
  4. Bind the CA certificates to the Gateway Virtual Server in the CA certificates section.

  5. Enable Device Certificates in the Citrix Gateway Virtual Server > Basic Settings > More section. Move the same CA certificates to the right.

Device Certificates in nFactor (AAA)

nFactor Endpoint Analysis also supports Device Certificates. OCSP (described earlier) is also required for this feature.

  1. It’s probably easier to search the menu for EPA than to actually navigate to Security > AAA – Application Traffic > Policies > Authentication > Advanced Policies > Actions > EPA.
  2. On the right, click Add.
  3. On the bottom right, click EPA Editor.
  4. Change the first drop-down to Common.
  5. Change the second drop-down to Device Certificate and then click Done
  6. Give the EPA Action a name and then click Create.
  7. You can now use this EPA Action in your nFactor configuration.
  8. On the Gateway Virtual Server, bind CA certificates as described in the previous section.
  9. On the AAA Virtual Server, click the pencil in the Basic Settings section.
  10. Click More.
  11. Near the bottom, click Add next to the CA for Device Certificate section to bind CA certificates. Then click OK.

User Experience

Users will be prompted to install the Endpoint Analysis plugin.

Click Yes to run the scan. Note: if the user is not an administrator of the local machine, then you must also install the Citrix Gateway Plug-in (VPN client) to handle the security restrictions.

If there are multiple certificates on the client machine, the user will be prompted to select one.

The chosen machine certificate is stored in %localappdata%\Citrix\AGEE\config.js. The user won’t be prompted for certificate selection again unless you delete this file.

This same folder contains nsepa.txt, which lets you troubleshoot device certificate checking. The most common issue is lack of permissions, which is handled by installing the Citrix Gateway VPN Plug-in. The Gateway VPN Plug-in version must match the firmware version.