NetScaler Gateway 11.1 RADIUS Authentication

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• RADIUS Overview
• Two-factor Policies Summary
• Create Two-factor Policies
• Bind Two-factor Policies to Gateway

RADIUS Overview

For two-factor authentication using Azure Multi-factor Authentication, see Jason Samuel How to deploy Microsoft Azure MFA & AD Connect with Citrix NetScaler Gateway

Citrix CTX125364 How to Configure Dual Authentication on NetScaler Gateway Enterprise Edition for Use with iPhone and iPad.

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.

• CTX205907 Dual-Password Field Shows in First Authentication When Connecting to NetScaler Gateway from Windows Receiver for instructions.
• CTX203775 Citrix Receiver and 2-Step Verification Incompatibility  💡

Two-factor authentication to NetScaler Gateway requires the RADIUS protocol to be enabled on the two-factor authentication product.

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 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.

Two-factor Policies Summary

When configuring the NetScaler 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 NetScaler 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 Receiver Self-service (native Receiver on mobile, Windows, and Mac), the authentication policies are swapped:

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

If you need to support two-factor authentication from both web browsers and Receiver Self-Service, 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

Create Two-factor Policies

Do the following to create the Two-factor policies:

1. Create an LDAP server.
2. For RADIUS, on the left, expand Authentication, and click Dashboard.
   
3. On the right, click Add.
   
4. Change Choose Server Type to RADIUS.
   
5. Give the server a name.
6. Specify the IP address of the RADIUS load balancing Virtual Server.
7. Enter the secret key specified when you added the NetScalers as RADIUS clients on the RADIUS server. Click Test Connection.
   
8. Scroll down and click Create.
   

   add authentication radiusAction RSA -serverIP 10.2.2.210 -serverPort 1812 -radKey Passw0rd

9. Since you can’t create authentication policies from the authentication dashboard, go to NetScaler Gateway > Policies > Authentication > RADIUS.
   
10. On the right, in the Policies tab, click Add.
    
11. Name it RSA-ReceiverSelfService or similar.
12. Select the RADIUS server created earlier.
13. 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.
14. Click Create.
    

    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

15. Create another 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

    

16. Go to the NetScaler Gateway\Policies\Authentication\LDAP node.
    
17. 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

    

Bind Two-factor Policies to Gateway

1. When you create or edit a NetScaler Gateway Virtual Server, bind the 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 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 NetScaler Gateway object, change the Logon type to Domain and security token.