NetScaler Gateway 11 RADIUS Authentication

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

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.

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 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 Native Citrix Receivers (non-browser including mobile), 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 both web browsers (PCs) and mobile devices, you’ll need at least four authentication policies as shown below.

Primary:

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

Secondary:

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

The policies are detailed below:

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 Create.
   
8. Since you can’t create authentication policies from the authentication dashboard, go to NetScaler Gateway > Policies > Authentication > RADIUS.
   
9. On the right, in the Policies tab, click Add.
   
10. Name it RSA-SelfService or similar.
11. Select the RADIUS server created earlier.
12. Enter an expression. You will need two policies with different expressions. The expression for Receiver Self-Service is HTTP.HEADER User-Agent CONTAINS CitrixReceiver.
13. Click Create.
    
14. 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-SelfService	REQ.HTTP.HEADER User-Agent CONTAINS CitrixReceiver	RSA
    RSA-Web	REQ.HTTP.HEADER User-Agent NOTCONTAINS CitrixReceiver	RSA

15. Go to the NetScaler Gateway\Policies\Authentication\LDAP node.
     
16. 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-SelfService	REQ.HTTP.HEADER User-Agent CONTAINS CitrixReceiver	LDAP-Corp
    LDAP-Corp-Web	REQ.HTTP.HEADER User-Agent NOTCONTAINS CitrixReceiver	LDAP-Corp

17. When you create the 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-Web	LDAP	Primary
    RSA-SelfService	RADIUS	Primary
    LDAP-Corp-SelfService	LDAP	Secondary
    RSA-Web	RADIUS	Secondary

18. 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.
    
19. On the StoreFront server, when creating the NetScaler Gateway object, change the Logon type to Domain and security token.