Duo for NetScaler - Basic Secondary Authentication Instructions with Classic Policies

1. Download the most recent Authentication Proxy for Windows from https://dl.duosecurity.com/duoauthproxy-latest.exe. Note that the actual filename will reflect the version e.g. duoauthproxy-6.4.1.exe. View checksums for Duo downloads here.
2. Launch the Authentication Proxy installer on the target Windows server as a user with administrator rights and follow the on-screen prompts.

   When installing, you can choose whether or not you want to install the Proxy Manager. The Proxy Manager is a Windows utility that helps you edit the Duo Authentication Proxy configuration, determine the proxy's status, and start or stop the proxy service. Learn more about using the Proxy Manager. Installing the Proxy Manager adds about 100 MB to the installed size.

   If you do not want to install the Proxy Manager, you may deselect it on the "Choose Components" installer screen before clicking Install.

To perform a silent install on Windows, issue the following from an elevated command prompt after downloading the installer (replacing version with the actual version you downloaded):

duoauthproxy-version.exe /S

Append /exclude-auth-proxy-manager to install silently without the Proxy Manager:

duoauthproxy-version.exe /S /exclude-auth-proxy-manager

If you installed the Duo Authentication Proxy Manager utility (available with 5.6.0 and later), click the Start Service button at the top of the Proxy Manager window to start the service.

To start the service from the command line, open an Administrator command prompt and run:

net start DuoAuthProxy

Alternatively, open the Windows Services console (services.msc), locate "Duo Security Authentication Proxy Service" in the list of services, and click the Start Service button.

Authentication Proxy v5.1.0 and later includes the authproxyctl executable, which shows the connectivity tool output when starting the service. The installer adds the Authentication Proxy C:\Program Files\Duo Security Authentication Proxy\bin to your system path automatically, so you should not need to specify the full path to authproxyctl to run it.

From an administrator command prompt run:

authproxyctl start

If the service starts successfully, Authentication Proxy service output is written to the authproxy.log file, which can be found in the log subdirectory.

If you see an error saying that the "service could not be started", open the Application Event Viewer and look for an Error from the source "DuoAuthProxy". The traceback may include a "ConfigError" that can help you find the source of the issue.

Stop and restart the Authentication Proxy service by either clicking the Restart Service button in the Duo Authentication Proxy Manager or the Windows Services console or issuing these commands from an Administrator command prompt:

net stop DuoAuthProxy & net start DuoAuthProxy

To stop and restart the Authentication Proxy using authproxyctl, from an administrator command prompt run:

authproxyctl restart

IMPORTANT: Citrix NetScaler 12.1 reached end of life on May 30, 2023, and NetScaler 13.0 reached end of life on July 15, 2024.

Duo does not support integrations beyond the third-party vendor's last date of support. Please review the Duo End of Sale, Last Date of Support, and End of Life Policy.

1. Log in to the NetScaler administrative interface.

2. Navigate to NetScaler Gateway → Virtual Servers or Citrix Gateway → Virtual Servers in the left panel of the administrative interface.

3. Select your existing Gateway Virtual Server, and then click Edit.

4. On the "VPN Virtual Server" page, click the plus sign (+) next to Basic Authentication to add a new authentication policy.

5. On the "Choose Type" page, select the RADIUS policy and Secondary type from the drop-down menus and click Continue.

   

6. On the next "Choose Type" screen, click the plus sign (+) next to the "Policy Binding" → "Select Policy" box.

7. On the "Create Authentication RADIUS Policy" page, enter a name for the policy (like CitrixWebPortal), and then click the plus sign (+) next to the "Server" box to create a new RADIUS server for Duo authentication for web browser clients.

8. On the "Create Authentication RADIUS Server" page, enter the information for your Duo Authentication Proxy server:

   Name	CitrixWebPortal (or another descriptive name)
   Server Name or IP Address	The hostname or IP address of your Duo Authentication Proxy server.
   Port	The port configured for radius_server_iframe on the Duo Authentication Proxy (1812 in the example)
   Time-out (seconds)	60
   Secret Key	The RADIUS secret shared with your Duo Authentication Proxy
   Confirm Secret Key	The RADIUS secret shared with your Duo Authentication Proxy

   If you use the Citrix Workspace app, click on More and set the “Group Vendor Identifier" to 3825.

   

9. Click Create to add the CitrixWebPortal RADIUS server and return to the "Create Authentication RADIUS Policy" page.

10. Click the Expression Editor link on the "Create Authentication RADIUS Policy" page to add an expression with the following details:

    Expression Type	General
    Flow Type	REQ
    Protocol	HTTP
    Qualifier	HEADER
    Operator	NOTCONTAINS
    Value*	CitrixReceiver
    Header Name*	User-Agent

    

11. When the Server and Expression information is correct click Create to save the new CitrixWebPortal policy and return to the "Choose Type" page.

    

12. On the "Choose Type" page, make sure the new RADIUS authentication policy you just created is selected. Set the Priority under "Binding Details" to 100 and click Bind.

    

13. Binding the new authentication policy returns you to the "VPN Virtual Server" page. Click the plus sign (+) next to Authentication again to add a second new authentication policy.

14. On the "Choose Type" page, select the RADIUS policy and Secondary type from the drop-down menus and click Continue.

    

15. On the next "Choose Type" screen, click the Add Binding button.

16. Click the plus sign (+) next to the "Policy Binding" → "Select Policy" box.

17. On the "Create Authentication RADIUS Policy" page, enter a name for the policy (like CitrixReceiver), and then click the plus sign (+) next to the "Server" box to create a new RADIUS server for Duo authentication for Citrix Receiver or Workspace clients.

18. On the "Create Authentication RADIUS Server" page, enter the information for your Duo Authentication Proxy server:

    Name	CitrixReceiver (or another descriptive name)
    Server Name or IP Address	The hostname or IP address of your Duo Authentication Proxy server.
    Port	The port configured for radius_server_duo_only on the Duo Authentication Proxy (18120 in the example)
    Time-out (seconds)	60
    Secret Key	The RADIUS secret shared with your Duo Authentication Proxy
    Confirm Secret Key	The RADIUS secret shared with your Duo Authentication Proxy
    Send Calling Station ID	Check this box in order to send the IP address of Citrix Receiver or Workspace clients to Duo

    

19. Click Create to add the CitrixReceiver RADIUS server and return to the "Create Authentication RADIUS Policy" page.

20. Click the Expression Editor link on the "Create Authentication RADIUS Policy" page to add an expression with the following details:

    Expression Type	General
    Flow Type	REQ
    Protocol	HTTP
    Qualifier	HEADER
    Operator	CONTAINS
    Value*	CitrixReceiver
    Header Name*	User-Agent

    

21. When the Server and Expression information is correct click Create to save the new CitrixReceiver policy and return to the "Choose Type" page.

    

22. On the "Choose Type" page, make sure the new RADIUS authentication policy you just created is selected. Set the Priority under "Binding Details" to 110 and click Bind.

    

23. Verify that your new policies for Receiver or Workspace and browser clients are both listed and are bound in the correct order. Click Close to save the new policy configuration.

    

24. Verify that you have two RADIUS policies for Secondary Authentication and click Done.

25. Save all of the changes made to the running config.

IMPORTANT: Citrix NetScaler 13.0 reached end of life on July 15, 2024.

Duo does not support integrations beyond the third-party vendor's last date of support. Please review the Duo End of Sale, Last Date of Support, and End of Life Policy.

With a Rewrite Policy

Rewrite policies can be bound to individual NetScaler virtual servers instead of globally to all virtual servers. Ensure that the Rewrite feature is enabled on your NetScaler by going to System → Settings → Configure Basic Features and verifying that the "Rewrite" feature is checked in the NetScaler administrative interface.

1. SSH in to your NetScaler.

2. Enter the following commands to create rewrite actions that will hide the second password field:

   add rewrite action rw_act_insert_DUO_ENABLED insert_after_all "HTTP.RES.BODY(120000).SET_TEXT_MODE(IGNORECASE)" "\" && !DUO_ENABLED\"" -search "text(\"if (pwc ==2\")"
   
    add rewrite action rw_act_insert_var_DUO_ENABLED insert_before_all "HTTP.RES.BODY(120000).SET_TEXT_MODE(IGNORECASE)" "\"var DUO_ENABLED = true;\"" -search "text(\"if (pwc ==2\")"

3. Next, enter the following commands to create rewrite policies that apply the actions created in step #2 to the gateway_login_form_view.js file:

   add rewrite policy rw_pol_insert_var_DUO_ENABLED "HTTP.REQ.URL.CONTAINS(\"gateway_login_form_view.js\")" rw_act_insert_var_DUO_ENABLED
   
    add rewrite policy rw_pol_insert_DUO_ENABLED "HTTP.REQ.URL.CONTAINS(\"gateway_login_form_view.js\")" rw_act_insert_DUO_ENABLED

4. In the NetScaler administrative interface, navigate to NetScaler → Virtual Servers or Citrix Gateway → Virtual Servers. Click on the virtual server where you added Duo secondary authentication to access its properties page.

5. Scroll down to the Policies section and click the plus sign (+) to add the Duo rewrite policies.

6. On the "Choose Type" page, select Rewrite from the "Choose Policy" drop-down and Response from the "Choose Type" drop-down. Click Continue.

   

7. On the next "Choose Type" page, click on the "Select Policy" Click to select field in the "Policy Binding" section of the page. This shows you the list of rewrite policies you created from the shell earlier. Select the rw_pol_insert_var_DUO_ENABLED policy and click the Select button to return to the "Choose Type" page.

8. When back on the "Choose Type" page, change the "Goto Expression" to NEXT. You usually do not need to change the "Priority" from the default value assigned. Click the Bind button to bind the first rewrite policy to your virtual server.

   

9. Click the plus sign (+) in the "Policies" section again to bind the second Duo rewrite policy. Once again, select Rewrite from the "Choose Policy" drop-down and Response from the "Choose Type" drop-down and then click Continue.

   

10. On the "Policy Binding page, click the Add Binding button. Click on the "Select Policy" Click to select field to bring up the list of policies. Select the rw_pol_insert_DUO_ENABLED policy and click the Select button to return to the "Policy Binding" page.

11. When back on the "Policy Binding" page, leave the "Goto Expression" set to END. You usually do not need to change the "Priority" from the default value assigned, just make sure that it has a greater number than the priority vaule assigned to the first bound policy (e.g. if the first one was priority 100 the second policy priority should be 110). Click the Bind button to bind the second rewrite policy to your virtual server.

    

12. Now you should see both "DUO_ENABLED" rewrite policies listed in the correct order (rw_pol_insert_var_DUO_ENABLED before rw_pol_insert_DUO_ENABLED). Click Close to finish.

    

13. Verify that you have two additional Rewrite policies listed under "Response Policies" and click Done.

14. Save all of the changes made to the running config.

15. Reboot the device.