SAML Authentication between Citrix & Microsoft with Azure MFA

Update to the latest cloud navigation.

As a result of increasing projects, here is a little how-to with the summary of my previous articles. The main points are:

• Azure AD Seamless Single Sign-On (PTA / PHS)
• SAML Authentication (Azure AD as IdP & Citrix Gateway as SP)
• Citrix Federated Authentication Service (FAS)
• Microsoft Azure Multi-Factor-Authentication with Conditional Access

Requirements

• Fully working Citrix Virtual Apps and Desktop Environment (StoreFront & DDC Minimum Version 7.9)
• NetScaler with successful base configuration & activated Enterprise or Platinum license (Minimum Version 12.1 Build 50+ for native workspace app, for browser Minimum Version 11.1)
• Configured Unified Gateway vServer
• Internal and external DNS entries for Unified Gateway vServer (e.g. citrix.deyda.net)
• Certificates for DNS entries (wildcard certificates are the easiest)
• Existing Azure Tenant with Azure-AD base configuration (Domain, AAD Sync) & activated Azure AD Premium license
• AD Connect version installed and configured (Minimum Version 1.1.644.0)
• Firewall release for *.msappproxy.net on port 443
• Domain administrator credentials for the domains that connected to Azure AD via AD Connect
• Installed Authenticator App on Test User Mobile Phone

Azure AD Seamless SSO (PTA / PHS)

You can find more detailed background information on this topic here.

Activation of Azure AD Seamless Single Sign-On

Activation Seamless SSO – AD Connect

I will now show you how to enable Pass-through Authentication and Password Hash Synchronization. Only one feature is needed to use Seamless SSO.

Activating Pass-through Authentication

To enable Pass-through Authentication, connect to the AD member on which AD Connect is installed.

• Start Azure AD Connect

• Click on Configure in the Welcome Screen

• Now click on Change user sign-in and confirm this with Next

• Enter the credentials of the Global Administrator and confirm the entry with Next

• Possibly another login mask is requested because of an MFA

• Select Pass-through authentication and then Enable single sign-on. Confirm with Next

• Under Single single-on click on Enter credentials

• In the following windows, enter the credentials of a local domain administrator and click OK

• Click on Configure to perform the described actions

• Confirm the successful execution in the Configuration complete window with Exit

Activating Password Hash Synchronization

To activate Password Hash Synchronization connect to the AD member on which AD Connect is installed.

• Start Azure AD Connect

• Click on Configure in the Welcome Screen

• Now click on Change user sign-in and confirm this with Next

• Enter the credentials of the Global Administrator and confirm the entry with Next

• Possibly another login mask is requested because of an MFA

• Select Password Hash Synchronization and then Enable single sign-on
• Confirm with Next

• Under Single single-on click on Enter credentials

• In the following windows, enter the credentials of a local domain administrator and click OK

• Click on Configure to perform the described actions

• Confirm the successful execution in the Configuration complete window with Exit

Local Active Directory

In the local Active Directory, you can now find a new computer object called AZUREADSSOACC. This object should be protected from deletion.

Azure Portal

In the Azure Portal you can also see the activated Seamless SSO methods.

• Log in to the Azure Portal with administrative credentials

• In the Azure Portal, click on Azure Active Directory > Azure AD Connect

• Then click on Azure AD Connect

• Click on Connect Sync in AAD Connect

• Now click on the Seamless SSO method (Seamless single sign-on or Pass-through authentication) that has been enabled via Azure AD Connect

Under Seamless single sign-on, domains enabled with Password Hash Synchronization can be checked.

For Pass-through authentication, a warning icon is displayed because the agent is stored on only one server.

According to Microsoft, this will be distributed over 3 internal servers.

Group Policy Object

In order for Seamless SSO to work on the end devices, some settings still have to be distributed via GPOs.

• Connect to a computer that has the Group Policy Management Console installed.

• Now adds the following settings to an existing or a new GPO
  • In the GPO, go to User / Computer Configuration > Adminstrative Templates > Windows Components > Internet Explorer > Internet Control Panel > Security Page

• Edit the Site to Zone Assignment List with the following values

Value Name	Value
login.microsoftonline.com	3
aadg.windows.net.nsatc.net	1
autologon.microsoftazuread-sso.com	1
secure.aadcdn.microsoftonline-p.com	1

Note:
If Seamless SSO is to be disabled for individual groups or users, the GPO must be turned to the Value 4 for these people.

• Then go to the path User / Computer Configuration > Adminstrative Templates > Windows Components > Internet Explorer > Internet Control Panel > Security Page > Intranet Zone

• Set the Allow updates to status bar via script entry to Enabled

Renew the Kerberos Decryption Key

Microsoft recommends rolling out the Kerberos Decryption Key at least every 30 days. This reduces the risk of spying on the Kerberos Decryption Key. Microsoft is working on the introduction of an automated function to perform this task.

To renew the Kerberos Decryption Key of the AZUREADSSOACC computer account, you must first download the Azure AD PowerShell module from the PowerShell Gallery.

• Start PowerShell as the administrator on the computer on which AD Connect is installed and run the following command:

• Navigate to the path C:\Program Files\Microsoft Azure Active Directory Connect and import the module AzureADSSO.psd1

• Execute the New-AzureADSSOAuthenticationContext command

• Enter the credentials of an Azure administrator in the following window.

• Then run Get-AzureADSSOStatus. This checks which domains are stored and activated in the Seamless SSO tenant.

• Then run the command $passwd = Get-Credential and enter the credentials of a local domain administrator in the following window.

• Finally, executes the following command to complete the update of the Decryption Key of the AZUREADSSOACC computer account.

This must be done for all domains configured for Seamless SSO.

SAML Authentication (Azure AD as IdP & Citrix Gateway as SP)

You can find more detailed background information on this topic here.

SAML Authentication with Azure AD as IdP and Citrix as SP

Active Directory

If you do not use the same UPN in Azure AD and in the local Active Directory, you still have to adjust it.

• To do this, open the Active Directory Domains and Trusts tool.

• In the tool, right-click on the top item (Active Directory Domains and Trusts) and select Properties.

• In the following window enter the desired domain (e.g. deyda.net) under Alternative UPN Suffixes and confirm the entry via Add
• Check that the domain name has been inserted correctly and confirm with OK

• Now you can bulk edit or manually adjust the UPN of the required users to the Azure-AD domain

Azure Active Directory

To connect our upcoming Service Provider, we now need to create a Enterprise application in the Azure Active Directory.

• To configure the Azure Active Directory, log in to Azure Portal

• In the Azure Navigation Panel, we click on Azure Active Directory.

• And click above on Create your own application

• In the following window enter the Name of the Enterprise app and select the checkbox next to Integrate any other application you don’t find in the gallery (Non-gallery)
• Confirm with Create

• Wait for the application to be created. Information can be obtained from the Notifications element at the top

• After successful creation of the application, you will be redirected to the Overview page of the application.

• If this does not happen, simply go to Azure Active Directory > Enterprise applications > All applications, find the new application you just created (e.g. CVAD) and click on it

• In the Enterprise application click on Single sign-on or 2. Set up single sign on

• Under Select a single sign-on method click on SAML

The following window configures the communication between the Identity Provider and Service Provider.

• Click on the pencil icon in the upper area with the number 1 to edit the Basic SAML Configuration.

• Enter here the following:
  • Identifier (Citrix Gateway Address, e.g. https://citrix.deyda.net)
  • Reply URL (Citrix Gateway Address with /cgi/samlauth, e.g. https://citrix.deyda.net/cgi/samlauth)
  • Relay State (NetScaler Gateway Adress with /CitrixAuthService/AuthService.asmx, e.g. https://citrix.deyda.net/CitrixAuthService/AuthService.asmx)
• Confirm your input with Save

Note !
The fields under Identifier and Reply URL appear only after clicking the Add identifier / Add reply URL links.

• The settings under point 2 Attributes & claims can remain in the existing standard

Note !
The settings in Attributes & Claims can be edited if not the Azure AD UPN should be passed to the local environment, but an alternative attribute should be used by storing the local login name.

• Under SAML Signing Certificate (Item 3), download the Certificate (Base 64) for the Service Provider (NetScaler)

Note !
The NetScaler can also be configured via Metadata URL, in the Enterprise Application this is called App Federation Metadata Url. Since I personally had only problems with it, I recommend the manual method described here.

Note !
The SAML Signing Certificate is valid for 3 years and must be renewed in time. Instructions can be found under Renewing the SAML Certificate.

• From area 4 (Set up OnPrem CVAD), copy the displayed URLs (Login URL, Azure AD Identifier & Logout URL) to a local file

To allow users to use SAML authentication for Citrix, they must be assigned to the application.

• Click on Users and groups.

• Now click on Add user/group

• Now select from the list the users who should be granted access (or select all users) and confirm this with Assign.

• I only authorised one test user (Test User 01) for this

NetScaler

Finally, the NetScaler (Citrix ADC) must be configured to communicate with the Identity Provider (Azure-AD).

• To do this, we log in to the Admin web interface of the NetScaler and navigate to Traffic Management > SSL > Certificates > Server Certificates.

• There, click Install to import the previously downloaded certificate of the enterprise app

• Enter the following and confirm the entry with Install
  • Certificate-Key Pair Name (Unique name for the SAML signature certificate, e.g. SAML-Azure-AD)
  • Certificate File Name (Downloaded signature certificate, e.g. Citrix FAS.cer)

• The installed certificate can not be found under Server or Client Certificates, but under Unknown Certificates

• Then we navigate to Security > AAA – Application Traffic > Virtual Servers to create the SAML Authentication Policy and Authentication vServer

• Under Authentication Virtual Servers, click Add to create a new vServer

• Now enter the following:
  • Name (Name of the vServer, e.g. Azure-AD_auth_VS
  • IP Address Type (Non Addressable)
• Click on OK

• In the following wizard click on No Server Certificate to connect your server certificate (not the IdP certificate !)

• Click in the Click to select area

• Select your NetScaler Server certificate (e.g. Wildcard certificate) and click Select

• Click on Bind

• If the certificate is attached (1 Server Certificate) click Continue

• Under the menu item Advanced Authentication Policies click on No Authentication Policy

• Click on Add under Select Policy

• Enter the following:
  • Name (Name of the Authentication Policy, e.g. saml_auth_pol)
  • Action Type (SAML)
  • Expression (HTTP.REQ.IS_VALID)
• Click on Add next to Action

• Now configure the Authentication SAML Server with the following parameters:
  • Name (Name of the SAML Authentication Server, e.g. saml_auth_server)
  • IDP Certificate Name (Certificate from the Azure-AD Application, e.g. SAML Auth)
  • Redirect URL (URL for logging in from the Azure AD application, e.g. https://login.microsoftonline.com/…/saml2)
  • Single Logout URL (URL for logging in from the Azure AD application, e.g. https://login.microsoftonline.com/…/saml2)
  • Signing Certificate Name (Server Certificate of the Citrix Gateway, e.g. Wildcard certificate)
  • Issuer Name (Identifier Entry of the Azure Enterprise App, e.g. https://citrix.deyda.net)
  • Reject Unsigned Assertion (Off)

Note !
If the configuration is to be done automatically, the checkbox next to Import Metadata must be selected and the previously copied App Federation Metadata Url must be stored in the window that then appears.

• Click on More and edit the following settings
  • Signature Algorithm (RSA-SHA256)
  • Digest Method (SHA256)
• Confirm the entry with Create

• Check the entries again and click Create

• Under Policy Binding controls the inputs and changes the following:
  • Goto Expression (END)
  • Confirm this with Bind

• If the Authentication Policy is connected click on Continue and Done

In order to complete the configuration on the NetScaler, we only need to bind the newly created SAML Authentication Policy to our Gateway Virtual Server.

• To do this, we navigate to NetScaler Gateway > Virtual Servers

• Select the gateway vServer previously configured for FAS in StoreFront (e.g. https://citrix.deyda.net = UG_VPN_ug_10.0.0.8_443) and click Edit

• Unbind all connected LDAP or RADIUS authentication policy from the vServer
• Click on the policies under Basic Authentication (e.g. 1 LDAP Policy)

• Select the policies and click Unbind

• Confirm the window with Yes

• Check that neither a policy is connected in Basic Authentication nor in Advanced Authentication

• On the right side, click Authentication Profile under Advanced Settings

• Click on Add under Authentication Profile

• Enter a name (e.g. saml_auth_profile) under Create Authentication Profile and click on Click to select under Authentication Virtual Server

• Select the previously created Authentication Virtual Server (Azure-AD_auth_VS) and click Select

• Confirm the entry by clicking on Create

• Click on OK and on Done

• Navigate to NetScaler Gateway > Global Settings to delete the single sign-on domain

• Click on Change Global Settings

• Delete the possible entry under Single Sign-on Domain.

• If necessary, the policies of the Gateway vServer must also be adjusted for Single Sign-on Domain

Important !
If NetScaler 13.1 (currently tested with build 12.51) is used and the Single Sign-on Domain field under Global Settings is filled, the configuration currently does not work.
Under NetScaler 13.1 the Override Global is not stored in the Session Policy if the field is empty. But this is needed for the SAML Auth.

Therefore, the Global Setting must be cleaned up under 13.1 and it must be checked that no Override Global has been stored under Single Sign-on Domain in the Session Policies of the Gateway vServer. Please check previously for any other gateway vServers, that the Global Setting for this field is not required and if so, enter it in the connected Session Policies.

• Furthermore, the policies of the Gateway vServer must also be adjusted regarding Session Time-out
• This value must be smaller than the timeout value of the connected store in StoreFront

CLI Command

The certificate must first be uploaded to the NetScaler appliance via WinSCP. It must be stored under the path /nsconfig/ssl/.

Example:

If the authentication policies are not known. These can be found out as follows. The session policies are also displayed.

Example:

Now we know the session policies and have to find out the session profiles for the adjustment.

Citrix Federated Authentication Service (FAS)

Certificate Authority

Next, a PKI environment must be created, if there is no Microsoft Enterprise PKI in the domain. Go for this on the machine that should receive this role. In my example, it is the domain controller itself.

• For this we go to the Server Manager and click Add Roles and Features

• Click through the wizard to the point Server Roles and select the item Active Directory Certificate Services
• Confirm the selection with Add Features

• Then click Next in the Server Roles, Features and AD CS tab

• Under the heading Role Services you select the following points:
  • Certification Authority
  • Certification Authority Web Enrollment

• If pop-up windows with additional features appear, you also confirm these with Add Features

• Complete the installation with Install

• Now select the Notifications item in Server Manager
• Click on Configure Active Directory Certificate Services

• In the following configuration, the default settings can be confirmed with Next

• In the following window select Certification Authority and confirm with Next

• Define your configuration and confirm the individual points with Next
• Configuration used by me:
  • Setup Type (Enterprise CA)
  • CA Type (Root CA)
  • Private Key (Create a new private key)
  • Cryptography for CA (RSA#Microsoft Software Key Storage Provider, 2048, SHA256)
  • CA Name (Name of the CA, e.g. Deyda-CA)
  • Validity Period (5 Years)

• Confirm the settings with Configure

Now the domain controller must be issued a certificate of the local CA.

• To do this, open the MMC on the domain controller

• Click on File and Add / Remove Snap-in …

• Now click on Certificates and on Add

• In the following window select Computer account and confirm it with Next

• Finally, close the window with OK

• Right-click on Personal and then on All Tasks > Request New Certificate…

• In the Certificate Enrollment window, select your Active Directory Enrollment Policy and click Next

• Select Domain Controller Authentication and confirm this with Enroll

Citrix Federated Authentication Service

Now we can install and configure the FAS server. In my example, I install the FAS Part on the StoreFront server.

• For this mount the ISO of your Virtual Apps & Desktops version and start autoselect.exe
• Then start the installation by clicking on Federated Authentication Service in the following window

• Click on “I have read, understand, and … ” and confirm it with Next

• Now confirm the following default settings with Next

• And click Next again

• Start the installation with Finish

• You may have to restart your server

• To perform the basic configuration of the FAS through the GPO, copy the ADMX / ADML files from the specified path of your FAS server (C:\Program Files\Citrix\Federated Authentication Service\PolicyDefinitions)

• Add them to the PolicyDefinitions Store of your Active Directory

• Create a new one or edit an existing GPO, which will be activated on the following systems:
  • FAS Server
  • StoreFront Server
  • VDA Worker

• In the GPO go to the path:

• Enter your FAS server in Federated Authentication Service

• Update your local GPOs on the FAS server by running gpupdate /force in the CMD

• Then check the registry that the required entry has been written to the system:

Or / And

• Now start the Citrix Federated Authentication Service Tool with the “run as administrator” parameter

• Under Connect to FAS Server you can see the list of FAS servers entered via GPO
• Select the desired server and click OK

• The following window configures the FAS
• Click on Deploy in the frame Deploy certificate templates

• Click on OK, so that the configuration is carried out automatically, in the background

• After successful setup, a green tick appears next to the frame
• Then click on Publish in the second frame (Set up a certificate authority)

• Under Certificate Authority, select your CA configured / created for FAS (e.g. DC01.deyda.local\CA-DEYDA) and click OK

• Upon successful setup, also a green tick appears next to the second frame
• Now click on Authorize at the third frame Authorize this service

• Here select your CA and click OK.

• Next to the third frame now appears a blinking circle, because the certificate request must be approved

• Reconnect to the server with the FAS CA and open the Server Manager
• In Server Manager, click Tools > Certification Authority

• In the Certification Authority console, click on Pending Requests

• There you right click on the request of your FAS server (e.g. DEYDA \ CTX01) and click on All Tasks > Issue

• Thereafter, the certificate appears under Issued Certificates

The now-approved certificate normally expires in 2 years.
Therefore, it is recommended to include this certificate in the monitoring so that you renew the certificate before it expires.

Here are the PowerShell commands to get the expiration date (Replace CTX01.deyda.local with your FAS server).

• After approving, also a green tick appears next to the third frame

• Now click on Create in the frame Create a Rule

• Click on Next to create the default rule

• In the Template section select Citrix_SmartcardLogon and click Next

• In the Certificate authority section select your FAS CA (e.g. DC01.deyda.local\CA-DEYDA) and click Next

• Select Allow in-session use if you want to support double hop scenarios
• Click on Next

• Under Access control click on Manage StoreFront access permissions

• In the following window you delete the default group Domain Computers

• Then add your StoreFront servers and give them the Assert Identity (Allow) right
• Confirm this with OK

• Confirm with Next

• Under Restrictions you can define the user and the VDA for which certificate authentication via FAS should be allowed

• Click on Manage user permissions
  You can restrict the users who can log in to Citrix via SAML. By default, the group Domain Users is stored here, which can stay that way.

• Click on Manage VDA permissions
  Under Manage VDA permissions you can narrow down the list of Citrix Workers to which you can log in via SAML. By default this stands on Domain Computers, which can stay that way.

• After everything is defined click on Next
• In the last window on Create

• Now all points have a green tick

StoreFront

Now we configure the StoreFront server so that it can talk to the FAS server.

• Go to your Citrix StoreFront console and make a note of your stores you want to configure for FAS (e.g. Store)

• Start PowerShell as administrator on a StoreFront server

• Execute the following commands in PowerShell (change the store path in line 2 to your store name):

• If you want to deactivate this again, e.g. for troubleshooting, you can do this with the following command in an administrative PowerShell (Adjust the line 2):

• Now open the Citrix StoreFront console again
• Click on Manage Authentication Methods in the panel on the right side

• Enable Pass-through from Citrix Gateway, if it is not enabled

• Then click on the gear on Pass-through from Citrix Gateway and on Configure Delegated Authentication

• In the following window, check the box next to Fully delegate credential validation to Citrix Gateway
• Click OK two times to close the windows

• Click, back in the main window of the StoreFront console, on Manage Citrix Gateways

• In Manage Citrix Gateways, you add a new Gateway or edit an existing one to connect to your NetScaler which will later be used as Service Provider

• In my case, I edited an existing Gaeway via Edit
• Configured the following under Authentication Settings:
  • Version (10.0 (Build69.4) or later)
  • VServer IP address (IP address of the Gateway VIP, e.g. 10.0.0.8)
  • Logon type (Domain)
  • Callback URL (Address of the Callback, e.g. https://citrix.deyda.net)
• Confirm the settings with Finish

Important !
The callback address must also be resolved correctly in the internal DNS.

• In the main menu of the StoreFront console, click on Configure Remote Access Settings

• Check that the item Allow users to access only resources delivered through StoreFront (No VPN tunnel) is activated

Delivery Controller

The XML Trust must still be activated on the Delivery Controller if this is not already activated.

• To do this you start a PowerShell as administrator on a Delivery Controller

• Now run the following command

Microsoft Azure Multi-Factor-Authentication with Conditional Access

You can find more detailed background information on this topic here.

Microsoft Azure MFA Cloud Service in Citrix ADC

Conditional Access

• First, we sign up with an administrative account in Azure Portal

• Click on Azure Active Directory > Security

• Click on Conditional Access

• Click on Named locations

• Create a new location based on the IP with a click on IP ranges location (via Countries location you can define whole countries to which you can then set special permissions)

• Configure the following for the workers
  • Name (e.g. Azure Worker)

• Click on the +

• Mark as trusted location (Checked)
• Click on Create

• Click under Policies on New policy

• In the new window, enter a Name for the policy (e.g. External MFA)
• Click on Users and groups
• Click under Include on All users

• Under Exclude click on Users and Groups
• Click on Select excluded users
• On the following window select the users that should not receive an MFA message, like the Break Glass User and the Sync Accounts
• Confirm with Done

• Click on Target resources
• Click on Select apps and select the previously created Enterprise App (e.g. Citrix FAS)
• Confirm with Done

• Click on Conditions > Locations
• Click under Configure on Yes

• Click under Exclude on Selected locations
• Select the previously created Location (e.g. Azure Worker)
• Confirm with Done

• Click under Access controls on Grant
• Select Grant access and Require multi-factor authentication
• Confirm with Select

• Click under Enable policy on On
• Confirm with Create

Convert users from per-user MFA to Conditional Access based MFA

Before the following script works, a connection to Azure AD must be established. Execute the following lines.

Save the following code into a PS1 file and execute it to swivel the MFA method.

List of configured MFA users

List of unconfigured MFA users

Authentication App

We now log in to MFA Setup with our test user to configure the Authentication App on the mobile device.

If the test user does not yet have a configured second factor, the following message appears.

The configuration can be started with Next.

• In the next window, select the type of the Second Factor (e.g, Mobile App)
• To simplify the configuration, you select to receive notifications for verification and click Next
• In the following window, a QR code is displayed, with which the Authentication App can be configured

• Open the Authenticator app on your device
• Click on the + symbol to add another account
• Select Business or School Account in the Accounts window

• With the following menu item Scan QR code you can scan the existing QR Code

• Now the test user is displayed in the account list

• In the browser you can confirm the configuration of the MFA service with Next and Finish

Result

If we now open the FQDN of the gateway (https://citrix.deyda.net) via browser.

We will be forwarded directly to Azure-AD and can authenticate ourselves there.

We get our Citrix resources listed and can start them.

Troubleshooting

Lessons learned from the field.

Cannot start app / Cannot start desktop

The user gets his resources displayed, but cannot start them and only gets the error message:

Cannot start app…

Cannot start desktop…

If this message appears only after FAS has been implemented, the usual suspects (machines not in Maintenance Mode, VDA is not registered, machines are shut down and so on), must be checked later.

Scenario 1

Checking the event log on the StoreFront shows the following.

Event 28 is generated when the application is started on the StoreFront server.

Failed to launch the resource ‘ ‘ using the Citrix XML Service at address ‘??’.

An unknown error occurred interacting with the Federated Autentication Service.

Citrix.Authentication.UserCredentialServices.FederatedAuthenticationServerFault,…Access Denied

This error message indicates a discrepancy in the FAS rule configuration. Mostly a different rule name is distributed than the one used in the FAS.

To check this, check the set Rule Name in the GPO or directly on the StoreFront in the registry.

To do this, go to the registry path and check the contents of DefaultRole:

Compares the rule name with the one stored in FAS under User Rules.

In my example, there was a discrepancy (GPO was configured to myRule and FAS to default) and this needs to be adjusted by editing the GPO and running a gpupdate /force on the StoreFront.

Scenario 2

If no event with ID 28 can be found on the StoreFront, the event log on the FAS server should be checked next.

Event 104 is generated when the application is started on the FAS server.

[S104] Server [] failed to assert UPN [] (UPN not allowed by role [default])

This indicates a misconfiguration in the specified FAS rule (here default). The StoreFront server (here SF1) is not authorized to make requests to the FAS server. But also the user could not be authorized in the FAS Rule.

To check this, check the settings in the FAS console regarding Manage StoreFront access permissions and Manage user permissions.

Here you can see that the StoreFront servers are not stored.

Expands the list of deposited machines with the required StoreFront servers.

Also check the Manage user permissions.

If the user or one of its groups is listed here and set to Deny, this should be corrected.

The request is not supported

The user gets his resources displayed and only gets the error message on the resource:

The request is not supported

Since we get to the VDA and there the message appears, check the event log on the target VDA.

Scenario 1

If event 3 occurs in the event log with the following content.

A Kerberos error message was received: on logon session

Error Code: 0x10 KDC_ERR_PADATA_TYPE_NOSUPP

This indicates that the domain controllers are missing the Domain Controller Authentication Certificate and/or the Kerberos Authentication Certificate. In the figure below you can see how it has to look like.

To do this, connect to the domain controller and check whether the above-mentioned certificates are available in the computer context. If not, simply add them so that the smart card logon works.

Szenario 2

If event 9 occurs in the event log.

The client has failed to validate the domain controller certificate for . The following error was returned from the certificate validation process: A certification chain processed correctly, but one of the CA certificates is not trusted by the policy provider.

Check the registry on the affected VDA at:

Normally, several CAs should be stored here.

If this is the case, export the internal CAs in DER format.

Then import the individual files on the VDA with the following command.

Then check via the registry that the CAs are now listed.

AADSTS50020: User account

After authentication, the user receives the following message.

AADSTS50020: User account

We can’t get to the Citrix farm and so check the Azure AD under Sign-in logs.

We find there the error code 50020, which matches the displayed error of the user.

Invalid username or password or Inval….

From the error message it is obvious that the entered user data does not match the Active Directory.

Scenario 1

Checking the user principal name (UPN) in the local Active Directory.

The local UPN (here User01@deyda.local) does not match the data entered and stored in Azure AD (here User01@deyda.net). This must be adjusted.

Scenario 2

If the UPN matches, check the Session Policies of the Citrix Gateway vServer, which is responsible for SAML authentication.

The Single sign-on domain must be empty in the session policies so that the correct username can be passed.

The user name or password is incorrect

The user gets the error message after starting the resource on the VDA.

The user name or password is incorrect

Since we get to the VDA and the message appears there, check the event log on the target VDA. There we find again the event ID 3 in the system log.

Event 3 declares:

A Kerberos error message was received: on logon session

Error Code: 0x3e KDC_ERR_CLIENT_NOT_TRUSTED

This indicates that the Certificate Revocation List has expired or is not accessible.

To check this, start the URL Retrieval Tool and check the CRLs from the Active Directory.

Ensures that the CRLs are up-to-date and provided (see figure).

Temporarily, the CRL query can also be disabled by entering the following registry key on the VDA.

Important !!!!
Remove this after testing.

Cannot complete your request

The user gets the error message after being connected for a while.

Cannot complete your request

This indicates that the timeout in StoreFront is set shorter than in NetScaler Gateway vServer.

To do this, adjust the timeout in either StoreFront or NetScaler so that the value in NetScaler is less than that in StoreFront (here StoreFront 20 minutes and Citrix Gateway 15 minutes).

The StoreFront Store settings are accessible in the specific store under Manage Receiver for Web Sites.

You cannot login using smart card

The user gets the error message after trying to access the gateway page. Mostly when the user has previously authenticated against another Azure service.

You cannot login using smart card

To solve this, the script.js file must be customized on all StoreFront servers. This can be found under C:\inetpub\wwroot\Citrix\<Store Name>Web\custom.

Insert the following line at the end of the file and save it.

Afterwards the IIS must be restarted. Start a CMD and execute the following command:

This must be executed on all StoreFront servers, on which the store connected in Citrix Gateway is stored.

Renewing the SAML certificate

Since my first article on this topic, is now almost 3 years ago, I have also come to the point of what needs to happen to the SAML certificate from the Azure AD Enterprise App when it expires. This needs to be reissued in Azure AD and then replaced in the NetScaler SAML Server Actions.

Azure Active Directory

To renew the certificate, this must be requested and downloaded under Enterprise application in Azure Active Directory.

• For this go to Azure Portal

• In the Azure Navigation Panel, click on Azure Active Directory

• In Azure Active Directory, click on Enterprise applications > All applications

• Search for the previously created application (e.g. Citrix FAS) and click on it.

• In the Enterprise application click on Single sign-on or on 2. Set up single sign on

• Under SAML Signing Certificate (area 3) the expiration date of the certificate for the service provider (NetScaler) can be checked (here 2.6.2022)
• Click on Edit

• In the following window click New Certificate to create a new certificate

• Now a new certificate with the status n/a appears under the existing certificate
• Click Save to finally create the certificate (Then a certificate thumbprint is also displayed)

• After confirming the new certificate via Save, the thumbprint appears and the status changes to Inactive

• To activate the new certificate, click on the three dots (…) in the row of the new inactive certificate
• In the following drop down window click on Make certificate active

• A message follows that with the confirmation of this message, the old certificate is deactivated and no SAML authentications can be signed with this certificate any longer

Important!
The certificate can also be downloaded before activation and imported / activated in NetScaler. I only go through system by system in these instructions.

• The new certificate is now active and the old one can no longer be used

• Now the new certificate can be downloaded via Certificate (Base64)

• After the certificate is downloaded, it has been renamed to Citrix FAS New, for better clarity.

NetScaler

Finally, the newly downloaded certificate must also be imported on the NetScaler.

• Open the admin web interface of the NetScaler and navigate to Traffic Management > SSL > Certificates > Server Certificates

• Click Install there to import the new certificate

• Enter the following and confirm with Install
  • Certificate-Key Pair Name (Unique name for the SAML signing certificate, e.g. Citrix FAS NEW)
  • Certificate File Name (Downloaded signature certificate, e.g. Citrix FAS – NEW.cer)

• The installed certificate is not found under Server or Client Certificates, but under Unknown Certificates.

• Then navigate to Security > AAA – Application Traffic > Policies > Authentication > Advanced Policies > Actions > SAML Actions to edit the existing SAML server action (here saml_auth_server)

• Now replace the certificate under IDP Certificate Name and select the newly downloaded one (here Citrix FAS NEW).