Citrix Federated Authentication Service – Advanced Configurations

In this article, I explain how you can use your own certificate template naming scheme, replacing the default names that are used by FAS. FAS high availability is also briefly explained.

Two challenges you may face when deploying FAS for a customer:

1. Customers have a specific naming scheme for certificate templates deployed via Active Directory Certificate Services, so the default names that FAS uses are unwanted. In this case, it is possible to create your own templates, define your own names, and then instruct FAS (via PowerShell) to use those instead.
2. Customers have a need for their services to be highly available. As such, you may also be tasked with configuring the FAS component to be highly available, which is quite simple given it acts in an active/active mode.

How to create FAS certificate templates with your own naming scheme

By default, FAS publishes three certificates to ADCS:

• Citrix_SmartcardLogon
• Citrix_RegistrationAuthority_ManualAuthorization
• Citrix_RegistrationAuthority

To create your own names, you can simply duplicate each of the three templates listed above:

Specifying the name of the template is performed on the General tab. Repeat this step for all three templates.

Adjust the xxSmartcardLogon certificate permissions so that each FAS server in your deployment has Enroll permission, and Authenticated Users have Read permission.

Under Certificate Templates in the ADCS console, you can delete the default issued FAS templates.

Then issue the new certificates via the ADCS console.

Next on your FAS server, launch PowerShell and run the below commands, replacing values with your own where appropriate:

1. asnp Citrix.Authentication.FederatedAuthenticationService.v1
2. New-FasAuthorizationCertificate -Address FAS1.jgspiers.com -CertificateAuthority DC.jgspiers.com\JGSPIERS-CA -CertificateTemplate “JGS-Citrix_RegistrationAuthority” -AuthorizationTemplate “JGS-CitrixRegistrationAuthority_ManualAuthorization”

Note: Take note of the Id from the console output, as we will use that in a near-future step.

This step allows the FAS server to send a certificate request for the Manual Authroization certificate to your Certificate Services server. This is a temporary certificate that is valid for 24 hours by default. The CA will not issue the certificate automatically, hence the need to manually issue it from the CA console. Log on to your CA console and issue the pending certificate request.

Once the certificate is issued, FAS uses the Manual Authorization certificate (JGS-CitrixRegistrationAuthority_ManualAuthorization) to automatically obtain the Registration Authority certificate (JGS-Citrix_RegistrationAuthority), which is valid for 2 years by default. The FAS server then deletes the Manual Authorization certificate (JGS-CitrixRegistrationAuthority_ManualAuthorization) as soon as it has a Registration Authority certificate (JGS-Citrix_RegistrationAuthority).

Any further Registration Authority certificate renewal will use the Citrix_RegistrationAuthority certificate template, thus you can unpublish the Citrix_RegistrationAuthority_ManualAuthorization template from AD CS if you wish.

Next run the following command:

1. Get-FasAuthorizationCertificate -Address FAS1.jgspiers.com

Note that two Authorization Certificates appear. The default one when you originally deployed FAS and pushed the default certificate templates out, and the new one you just enrolled for.

Using the Id value that you captured in an earlier step, we can identify which the other default Authorization Certificate by its Id, which we want to delete. Run the following command, replacing values with your own where appropriate:

1. Remove-FasAuthorizationCertificate -Address FAS1.jgspiers.com -Id 4d32dd77-e09f-481a-a2d2-a8998a63761f

Using the Id value that you captured in an earlier step, run the following command, replacing values with your own where appropriate:

1. New-FasCertificateDefinition -Address FAS1.jgspiers.com -CertificateAuthorities DC.jgspiers.com\JGSPIERS-CA -MsTemplate “JGS-CitrixSmartcardLogon” -AuthorizationCertificate 41452431-0551-49b7-8f27-aff416be065c

You can view the new Certificate Definition by running the following command:

1. Get-FasCertificateDefinition -Address FAS1.jgspiers.com

Note: If you see more than one Certificate Definition here, you will probably want to delete them. For example, the default definition may appear if you have already created a FAS rule.

The next step involves creating a FAS rule, which will link permissions to your newly created Certificate Definition. Open the Federated Authentication Service Configuration console and browse to the User Rules tab. Click on Add.

Specify a name and then click Ok.

Using the drop-down, select your Certificate Authority.

Using the drop-down, select the Citrix_SmartcardLogon default certificate template. We will later use PowerShell to change this to the template we created earlier.

Configure other settings as desired. The configuration of each remaining item is explained in more detail here

Click Apply.

Now run the following command:

1. Get-FASRule -Address FAS1.jgpiers.com

Notice the FAS rule that has been created. You now need to change the Certificate Definition to the one you created earlier. To do so, run the following command, replacing values with your own where appropriate:

1. Set-FasRule -Address FAS1.jgspiers.com -Name JGS-Rule -CertificateDefinitions JGS-CitrixSmartcardLogon

To clean up the Certificate Definition that was created by the Federated Authentication Service Configuration GUI, run the following commands, replacing values with your own where appropriate:

1. Get-FasCertificateDefinition -Address FAS1.jgspiers.com
2. Remove-FasCertificateDefinition -Address FAS1.jgspiers.com -Name JGS-Rule_Definition

Finally, create a Group Policy that applies to your StoreFront servers and informs them of the new FAS rule you have created.

Reboot your StoreFront servers so they pick up the new rule. A gpupdate via CMD is not enough.

You can tell when the rule has been picked up by StoreFront by looking at the HKLM\SOFTWARE\Policies\Citrix\Authentication\UserCredentialService registry key.

For high availability, you simply perform the same steps on your additional FAS servers, to make sure the configuration is the same. As previously mentioned, FAS works in an active/active mode. Be sure to update the Federated Authentication Service Group Policy setting by clicking Show beside DNS Addresses.

Enter the name of each FAS server you want to use. Click OK.