Duo Two-Factor Authentication for SonicWall SRA or SMA 100 Series SSL VPN with RADIUS and Duo Prompt

If you are using SonicWall Mobile Connect client or SonicWall's Global VPN Client using IPsec, or an unsupported device as listed below, then see the VPN Client Instructions to configure the SonicWall device to use Duo Security's push authentication. The Duo Prompt shown in browsers does not work with SonicWall client VPN applications.

Other types of SonicWall devices (such as the SMA 1000 series, NSA series, or Aventail) may also work with Duo's RADIUS Application.

We support the Duo web-based prompt with the following:

• SMA 100 series devices (SMA 200, SMA 400, and SMA 500v) with 9.0.0.2-13 or later v9 firmware.
  • SonicWall has issued a zero-day vulnerability alert for firmware versions below 9.0.0.10.
• SMA 100 series devices (SMA 200, SMA 400, and SMA 500v) with v10 firmware.
  • SonicWall discontinued SMA v10.0 support in October 2020. SonicWall Product Lifecycles

We do not support the Duo web-based prompt with:

• SMA 100 series devices or upgraded SRA devices with firmware versions before 9.0.0.2-13. SonicWall discontinued SMA v8.x support in September 2019, and discontinued v9.0.x support in October 2021. SonicWall Product Lifecycles
• SRA devices which have reached end of life, which includes SRA 1600, SRA 4600, SRA EX6000, and SRA EX7000. No update to 9.0.0.10 to address this zero-day vulnerability alert is available for these end-of-life SRA appliances. Use at your own risk.
• SMA 1000 series devices which run v11 or v12 firmwares.
• NSA, TZ, or EX (Aventail) devices
• Devices that run SonicOS firmware

Sonicwall introduced a new "Contemporary mode" for SMA in v10.2. This mode may prevent display of the Duo prompt. The issue displaying the Duo prompt in "Contemporary mode" was fixed in SMA firmware update 10.2.1.0-17. If you have issues with the v10 "Contemporary mode" and cannot update your device firmware, access the "Classic mode" login page by changing the VPN login URL in your browser from https://<your SMA VPN portal>/spog/welcome to https://<your SMA VPN portal>/cgi-bin/welcome. There is no setting in the SMA config to force use of "Classic mode".

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 SonicWall SMA/SRA SSL VPN users before you begin to deploy Duo.

To integrate Duo with your SonicWall SMA/SRA SSL VPN, 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 SonicWall SMA/SRA SSL VPN, 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 SonicWALL SRA SSL VPN 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 SonicWALL SMA/SRA SSL VPN

Next, we'll set up the Authentication Proxy to work with your SonicWALL SMA/SRA SSL VPN. 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=sonicwall_sra
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 SonicWall SRA SSL VPN

Configure the Portal Settings

You can add Duo authentication to an existing remote access portal, or you can create a new portal to use with Duo. However, the portal you choose to use with Duo should be dedicated for Duo authentication, with the Duo RADIUS domain you create later in this document bound to it. Follow these steps to create a new portal.

1. Log in to the SonicWall administrative interface.

2. In the left menu, navigate to Portals → Portals.

3. Click on Add Portal.

4. Navigate to the General tab.

5. In the Portal Name field, enter "Duo-Portal".

6. On the General tab, add the following to the end of the text in the Login Message box:

   <script src="https://API_HOSTNAME/frame/hosted/Duo-SonicWALL-SRA-v1.js"></script>

   Replace API_HOSTNAME with your API hostname (i.e. api-XXXXXXXX.duosecurity.com)

7. Select the Display custom login page check box.

8. Select the Display login message on custom login page check box.

   

9. Click on the Virtual Host tab.

10. Enter your desired Virtual Host Domain Name and select a Virtual Host Certificate to secure the connection with SSL (see the SonicWALL administration guide for your device to learn how to import certificates).

    

11. Click OK to save the settings.

Add a RADIUS Domain

1. In the left menu of the SonicWall console, navigate to Portals → Domains.

2. Click on Add Domain.

3. Select Radius from the Authentication type drop-down.

4. In the Domain Name field, "Duo-RADIUS" or another unique name.

5. Under Primary Radius server, enter the following information:

   Radius server address	The IP address of your Duo Authentication Proxy
   Radius server port	1812
   Secret password	The RADIUS secret shared with your Duo Authentication Proxy
   Radius Timeout (Seconds)	Increase to 60

6. For the Portal name, select the portal(s) that should use this new RADIUS domain from the list.

   

7. Click Submit to save the settings.

Update CSP for Duo

1. Navigate to the SMA System → Administration page or the SMA Internal Settings page at https://<your SMA IP or hostname>/cgi-bin/diagsettings (depending on your firmware version).

2. Scroll down to the "Content Security Policy Settings" setting and enter *.duosecurity.com as the "Content Security Policy URL". Separate multiple values in that field with a semi-colon (;) if necessary.

3. Click Accept to save the settings.

Test Your Setup

To test your setup, open the Duo-Portal URL for your SonicWall SMA VPN (if running v10 firmware prior to 10.2.1.0-17 ensure you use the "Classic mode" version of the Duo-Portal URL for your SonicWall SMA VPN i.e. https://<your SMA VPN portal>/cgi-bin/welcome). Make sure to select Duo Domain from the Domain drop-down list.

After you complete primary authentication, the Duo enrollment/login prompt appears.

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 the SonicWall SRA Frequently Asked Questions (FAQ) page or try searching our SonicWall SRA Knowledge Base articles or Community discussions. For further assistance, contact Support.

Network Diagram

1. Primary authentication initiated to SonicWall SRA
2. SonicWall SRA send authentication request to Duo Security’s authentication proxy
3. Primary authentication using Active Directory or RADIUS
4. Duo authentication proxy connection established to Duo Security over TCP port 443
5. Secondary authentication via Duo Security’s service
6. Duo Authentication Proxy receives authentication response
7. SonicWall SRA access granted