Citrix - Web Interface

Citrix Web Interface 5.4 is part of XenApp 6.5, which is an end-of-life product. See the Citrix Web Interface 5.4 FAQ for additional information. Consider updating to Citrix Gateway and StoreFront for application delivery.

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 Web Interface users before you begin to deploy Duo.

To integrate Duo with your Citrix Web Interface, 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 Web Interface, 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 operating systems for the system hosting the Duo Authentication Proxy:

• Windows Server 2016 or later
• CentOS 7
• CentOS Stream 8 or later
• Fedora 37 or later
• Red Hat Enterprise Linux 7 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.
3. Click Protect an Application and locate RADIUS 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 Duo Only Authentication

At the top of your authproxy.cfg, create a [duo_only_client] section. This section has no additional parameters to configure.

[duo_only_client]

When using the [duo_only_client] configuration, the Authentication Proxy will ignore primary credentials and perform Duo factor authentication only.

Configure the Proxy for Your Citrix Web Interface

Next, you need to set up the Authentication Proxy to work with your Citrix Web Interface. Create a [radius_server_duo_only] section and add the properties listed below. If you've already set up the Duo Authentication Proxy for a different RADIUS Duo-only application, append a number to the section header to make it unique, like [radius_server_duo_only2].

Required

Optional

A completed config file for radius_server_duo_only with no primary authenticator should look something like:

[duo_only_client]
 
[radius_server_duo_only]
ikey=DIXXXXXXXXXXXXXXXXXX
skey=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
api_host=api-XXXXXXXX.duosecurity.com
failmode=safe
radius_ip_1=5.6.7.8
radius_secret_1=radiussecret1
port=1812

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 Citrix Web Interface

Configure Your Citrix Web Interface Server

1. Log in to the Citrix Web Interface Management Console.
2. Navigate to XenApp Web Sites and click on Authentication Methods.
3. Confirm that only Explicit is checked and click properties
   
4. Click on Two-Factor Authentication and select RADIUS for the Two-factor Setting.
5. Add a RADIUS server and enter the authentication proxy IP address as the server address and 1812 for the server port. Configure the Timeout to 60 seconds and save your configuration.
   
6. Create a new text file in the Citrix Web Interface \conf folder called radius_secret.txt.
   Type the radius_secret from the authentication proxy configuration in the radius_secret.txt file.
   
   (The location for this file is given by the RADIUS_SECRET_PATH configuration value in the web.config file (for sites hosted on IIS) or web.xml file (for sites hosted on Java application servers). The location given is relative to the \conf folder for sites hosted on IIS and relative to the /WEB_INF directory for sites hosted on Java application servers.) Typically the location will be similar to: C:\inetpub\wwwroot\Citrix\Xenapp\conf.
7. On the Citrix Web Interface server open the web.config (IIS Hosted) or web.xml (Java Apps) file and add the Citrix Web Interface IP address as the "RADIUS_NAS_IP_ADDRESS".
   

Test Your Setup

1. First enroll users by using the Duo Security's Bulk Enrollment feature. See our documentation for Bulk Enrollment in the Administration Guide.
2. Once users are enrolled, start Your Citrix Web Interface Client and enter your username and password.
   

Duo two-factor login for jdoe

  Enter a passcode or select one of the following options:
  
  1. Duo Push to XXX-XXX-1234
  2. Phone call to XXX-XXX-1234
  3. SMS passcodes to XXX-XXX-1234
  
  Passcode or option (1-3)
  

In the text response area, type in the number that matches the option you want to use to log in. For example, to log in with Duo Push after receiving the above challenge prompt, enter 1, and then approve the Duo Push request you receive.

Instead of typing in the number that corresponds to the listed options, you may also enter a Duo factor option:

If you wanted to use Duo Push (rather than a passcode) to authenticate, you would enter:

push

You can also specify a number after the factor name if you have more than one device enrolled (as the automatic push or phone call goes to the first capable device attached to a user). So you can enter phone2 or push2 if you have two phones enrolled and you want the authentication request to go to the second phone.

The format of the Duo RADIUS text challenge prompt may change if you have multiple authentication devices enrolled in Duo, due to the character length limit of a RADIUS packet. If we detect that the user logging in has too many devices to list by number with full details the Duo proxy will automatically switch to a compact format, like this.

Choose a secondary factor from (`push1`, `phone1`, `sms1`) or enter passcode:

Respond to this prompt in the same way, by typing in either the name of a Duo factor listed or a number that matches a factor's position in the list.

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.