Overview

To integrate Duo with your SonicWALL SRA SSL VPN, you will need to install a local proxy service on a machine within your network. This Duo proxy server also acts as a RADIUS server — there's usually no need to deploy a separate additional RADIUS server to use Duo.

Once configured, Duo sends your users an automatic authentication request via Duo Push notification to a mobile device or phone call after successful primary login.

This configuration doesn't support inline self-service enrollment. You'll need to create your users in Duo ahead of time using one of our other enrollment methods, like directory sync or CSV import. Read the enrollment documentation to learn more.

First Steps

You should already have a working primary authentication configuration for your SonicWALL SRA SSL VPN users before you begin to deploy Duo.

Locate (or set up) a system on which you will install the Duo Authentication Proxy. The proxy supports Windows and Linux systems (in particular, we recommend Windows Server 2012 R2 or later, Red Hat Enterprise Linux 7 or later, CentOS 7 or later, or Debian 7 or later).

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 this Application to get your integration key, secret key, and API hostname. See Getting Started for help.

Install the Duo Authentication 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).

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:

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. 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. In most cases, this means configuring the Proxy to communicate with Active Directory or RADIUS.

Active Directory

To use Active Directory as your primary authenticator, add an [ad_client] section to the top of your config file. Add the following properties to the section:

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
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 SRA SSL VPN

Next, we'll set up the Authentication Proxy to work with your SonicWALL SRA SSL VPN. Create a [radius_server_auto] section with the following properties:

Required

Optional

A completed config file that uses Active Directory 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_auto]
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 when done.

Start the Proxy

net start DuoAuthProxy

net stop DuoAuthProxy & net start DuoAuthProxy

# /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.

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. 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" or another unique name.

   

6. Click on the Virtual Host tab.

7. Enter your desired Virtual Host Domain Name.

   

8. Click Accept to save the settings.

Add a RADIUS Domain

1. Log in to the SonicWALL administrative interface.
2. In the left menu, navigate to Portals → Domains.
3. Click on Add Domain.
4. Select Radius from the Authentication type dropdown.
5. In the Domain Name field, "Duo-RADIUS" or another unique name.

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

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

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

   

   Click Accept to save the settings.

Test Your Setup

Configure your SonicWALL Mobile Connect app to connect to the Portal that is using the Duo RADIUS domain for authentication.

To test your setup, attempt to log in to your newly-configured system as a user enrolled in Duo with an authentication device. When you enter your username and password, you will receive an automatic push or phone callback. Alternatively you can add a comma (",") to the end of your password, followed by a Duo passcode.

For example, given a username 'bob', with password 'password123' and a Duo passcode '123456', you would enter:

username: bob
password: password123,123456

In addition, you may also enter the name of an out-of-band factor in lieu of a passcode. You may choose from the following factor names:

Returning to the previous example, if you wanted to use Duo Push (rather than a passcode) to authenticate, you would enter:

username: bob
password: password123,push

You can also specify a number after the factor name if you have more than one device enrolled. So you can enter phone2 or push2 if you have two phones enrolled.

Troubleshooting

Need some help? 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