Citrix Access Gateway

Citrix Access Gateway is an end of life product. See the Citrix Legacy Product Matrix for additional information. Consider updating to NetScaler.

First Steps

Before moving on to the deployment steps, it's a good idea to familiarize yourself with Duo administration concepts and features like options for applications, available methods for enrolling Duo users, and Duo policy settings and how to apply them. See all Duo Administrator documentation.

You should already have a working primary authentication configuration for your Citrix Access Gateway users before you begin to deploy Duo.

To integrate Duo with your Citrix Access Gateway, you will need to install a local Duo proxy service on a machine within your network. This Duo proxy server will receive incoming RADIUS requests from your Citrix Access Gateway, contact your existing local LDAP/AD or RADIUS server to perform primary authentication, and then contact Duo's cloud service for secondary authentication.

If you are already running a Duo Authentication Proxy server in your environment, you can use that existing host for additional applications, appending the new configuration sections to the current config. You don't have to set up a new Authentication Proxy server for each application you create. However, there are some cases where it might make sense for you to deploy a new proxy server for a new application, like if you want to co-locate the Duo proxy with the application it will protect in the same data center.

We recommend the following 64-bit operating systems for the system hosting the Duo Authentication Proxy:

• Windows Server 2016 or later
• CentOS Stream 9 or later
• Fedora 39 or later
• Red Hat Enterprise Linux 7 or later
• Rocky Linux 9 or later
• Ubuntu 20.04 LTS or later
• Debian 11 or later

The Duo End of Sale, Last Date of Support, and End of Life Policy states that Duo does not offer support for integrations running on operating system versions beyond the vendor’s stated Last Date of Support date.

See detailed Authentication Proxy operating system performance recommendations in the Duo Authentication Proxy Reference.

We do not recommend installing the Duo Authentication Proxy on the same Windows server that acts as your Active Directory domain controller or one with the Network Policy Server (NPS) role. If you must co-locate the Duo Authentication Proxy with these services, be prepared to resolve potential LDAP or RADIUS port conflicts between the Duo service and your pre-existing services.

Then you'll need to:

1. Sign up for a Duo account.
2. Log in to the Duo Admin Panel and navigate to Applications → Protect an Application.
3. Locate the entry for Citrix Access Gateway with a protection type of "2FA" in the applications list. Click Protect to get your integration key, secret key, and API hostname. You'll need this information to complete your setup. See Protecting Applications for more information about protecting applications in Duo and additional application options.

Install the Duo Authentication Proxy

If you will reuse an existing Duo Authentication Proxy server for this new application, you can skip the install steps and go to Configure the Proxy.

The Duo Authentication Proxy can be installed on a physical or virtual host. We recommend a system with at least 1 CPU, 200 MB disk space, and 4 GB RAM (although 1 GB RAM is usually sufficient). See additional Authentication Proxy performance recommendations in the Duo Authentication Proxy Reference.

We do not recommend installing the Duo Authentication Proxy on the same Windows server that acts as your Active Directory domain controller or one with the Network Policy Server (NPS) role. If you must co-locate the Duo Authentication Proxy with these services, be prepared to resolve potential LDAP or RADIUS port conflicts between the Duo service and your pre-existing services.

duoauthproxy-version.exe /S

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

sudo ./duoauthproxy-build/install --install-dir /opt/duoauthproxy --service-user duo_authproxy_svc --log-group duo_authproxy_grp --create-init-script yes

Configure the Proxy

After the installation completes, you will need to configure the proxy.

The Duo Authentication Proxy configuration file is named authproxy.cfg, and is located in the conf subdirectory of the proxy installation. With default installation paths, the proxy configuration file will be located at:

Note that as of v4.0.0, the default file access on Windows for the conf directory is restricted to the built-in Administrators group during installation.

The configuration file is formatted as a simple INI file. Section headings appear as:

[section]

Individual properties beneath a section appear as:

name=value

The Authentication Proxy may include an existing authproxy.cfg with some example content. For the purposes of these instructions, however, you should delete the existing content and start with a blank text file.

Duo Authentication Proxy Manager

The Duo Authentication Proxy Manager is a Windows utility for managing the Authentication Proxy installation on the Windows server where you install the Authentication Proxy. The Proxy Manager comes with Duo Authentication Proxy for Windows version 5.6.0 and later.

The Proxy Manager cannot manage remote Duo Authentication Proxy servers, nor can you install the Proxy Manager as a stand-alone application. There is no Proxy Manager available for Linux. The Proxy Manager only functions as part of a local Duo Authentication Proxy installation on Windows servers.

Learn more about using the Proxy Manager in the Duo Authentication Proxy Reference before you continue.

To launch the Proxy Manager utility:

• Open the Start Menu and go to Duo Security.
• Click the Duo Authentication Proxy Manager icon to launch the application. You must have administrative privileges on the Windows server and accept the prompt for elevation.
• The Proxy Manager launches and automatically opens the %ProgramFiles%\Duo Security Authentication Proxy\conf\authproxy.cfg file for editing.

Use the Proxy Manager editor on the left to make the authproxy.cfg changes in these instructions. As you type into the editor, the Proxy Manager will automatically suggest configuration options. Accepting these suggestions helps make sure you use the correct option syntax.

As you follow the instructions on this page to edit the Authentication Proxy configuration, you can click Validate to verify your changes (output shown on the right).

When you complete the Authentication Proxy configuration steps in this document, you can use the Save button to write your updates to authproxy.cfg, and then use the authproxy.cfg button to start the Authentication Proxy service before continuing on to the next configuration steps.

If you do not use the Proxy Manager to edit your configuration then we recommend using WordPad or another text editor instead of Notepad when editing the config file on Windows.

Configure the Proxy for Your Primary Authenticator

In this step, you'll set up the Proxy's primary authenticator — the system which will validate users' existing passwords. Determine which type of primary authentication you'll be using, and create either an Active Directory/LDAP [ad_client] client section, or a RADIUS [radius_client] section as follows.

Active Directory

Add an [ad_client] section if you'd like to use an Active Directory domain controller (DC) or LDAP-based directory server to perform primary authentication. This section accepts the following options:

Required

search_dn=DC=example,DC=com

Optional

security_group_dn=CN=DuoVPNUsers,OU=Groups,DC=example,DC=com

For example:

[ad_client]
host=1.2.3.4
host_2=1.2.3.5
service_account_username=duoservice
service_account_password=password1
search_dn=DC=example,DC=com
security_group_dn=CN=DuoVPNUsers,OU=Groups,DC=example,DC=com

For advanced Active Directory configuration, see the full Authentication Proxy documentation.

RADIUS

To use RADIUS as your primary authenticator, add a [radius_client] section to the top of your config file. Then add the following properties to the section:

Required

Optional

For example:

[radius_client]
host=1.2.3.4
host_2=1.2.3.5
secret=radiusclientsecret

In addition, make sure that the RADIUS server is configured to accept authentication requests from the Authentication Proxy.

For advanced RADIUS configuration, see the full Authentication Proxy documentation.

Configure the Proxy for Your Citrix Access Gateway

Next, we'll set up the Authentication Proxy to work with your Citrix Access Gateway. Create a [radius_server_iframe] section and add the properties listed below. If you've already set up the Duo Authentication Proxy for a different RADIUS iframe application, append a number to the section header to make it unique, like [radius_server_iframe2].

Required

Optional

A completed config file, using Active Directory as the primary authenticator, should look something like:

[ad_client]
host=1.2.3.4
service_account_username=duoservice
service_account_password=password1
search_dn=cn=Users,dc=example,dc=com
 
[radius_server_iframe]
type=citrix
ikey=DIXXXXXXXXXXXXXXXXXX
skey=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
api_host=api-XXXXXXXX.duosecurity.com
radius_ip_1=5.6.7.8
radius_secret_1=radiussecret1
client=ad_client
port=1812
failmode=safe

Make sure to save your configuration file in your text editor — or validate and save in the Proxy Manager for Windows — when you're finished making changes.

Start the Proxy

net start DuoAuthProxy

authproxyctl start

net stop DuoAuthProxy & net start DuoAuthProxy

authproxyctl restart

# /opt/duoauthproxy/bin/authproxyctl start

# /opt/duoauthproxy/bin/authproxyctl status

# /opt/duoauthproxy/bin/authproxyctl restart

If you modify your authproxy.cfg configuration after initial setup, you'll need to stop and restart the Duo Authentication Proxy service or process for your change to take effect.

You can view information about your Authentication Proxy in the Authentication Proxy Dashboard.

Configure Your Citrix Access Gateway

Add a RADIUS authentication profile

1. Log in to the Citrix Access Gateway administrative interface.
2. Navigate to Management → Authentication Profiles in the administrative interface.
3. Click the Add button and select RADIUS to create a new RADIUS authentication profile.
4. In the RADIUS Properties dialog, enter the following information:

   Profile name

   Duo RADIUS

5. Next, click the New button in the Servers list section, and enter the following information:

   Server	The IP address of your Duo Authentication Proxy
   Shared secret	The RADIUS secret shared with your Duo Authentication Proxy
   Confirm secretg	The RADIUS secret shared with your Duo Authentication Proxy

6. Click the OK button to add the RADIUS server.

   
7. Click the Save button to save the new authentication profile.:

Add/configure a logon point

1. Navigate to Management → Logon Points in the administrative interface.
2. Click the Add button to add a new logon point. Alternately, you can modify an existing logon point by selecting it and clicking the Edit button.

3. Select Duo RADIUS as the primary authentication profile under Authentication Profiles and fill in any additional required fields.

   
4. Click the Save or Update button to save the logon point settings.

Test Your Setup

To test your setup, go to the URL you normally use to log in to your Citrix Access Gateway. After you complete the primary authentication, Duo enrollment/login should appear.

Troubleshooting

Need some help? Review troubleshooting tips for the Authentication Proxy and try the connectivity tool included with Duo Authentication Proxy 2.9.0 and later to discover and troubleshoot general connectivity issues.

Also take a look at our Citrix Knowledge Base articles or Community discussions. For further assistance, contact Support.