First Steps

To integrate Duo with your Palo Alto, you will need to install a local proxy service on a machine within your network. Before proceeding, you should 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 6 or later, CentOS 6 or later, or Debian 6 or later).

This Duo proxy server also acts as a RADIUS server — there's no need to deploy a separate RADIUS server to use Duo.

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 Palo Alto 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 Palo Alto GlobalProtect

Next, we'll set up the Authentication Proxy to work with your Palo Alto GlobalProtect. 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

Configure Your Palo Alto GlobalProtect Gateway

This configuration has been tested with PAN-OS 5.0.6 to 7.0.1 and GlobalProtect 1.2.5.

Add the Duo RADIUS server

1. Log in to the Palo Alto administrative interface.
2. On the Device tab, navigate to Server Profiles, then RADIUS.
3. Click the Add button to add a new RADIUS server profile.
4. In the Name field, enter Duo RADIUS, and in the Timeout field enter 30.

5. Under the Servers section, click the Add button to add a RADIUS server, and enter the following information:

   Property	Value
   Server	Type in Duo RADIUS or any name you prefer.
   IP Address	Enter the IP address of your Duo Authentication Proxy.
   Secret	Enter the RADIUS secret shared with your Duo Authentication Proxy.
   Port	Enter 1812 (or whichever port configured on your Duo Authentication Proxy).

6. Click OK to save the RADIUS server profile.

   

Add an Authentication Profile

1. On the Device tab, navigate to Authentication Profile.

2. Click the New... button to add a new authentication profile, and enter the following information:

   Property	Value
   Profile Name	Enter Duo or any name you prefer.
   Authentication	Select RADIUS from the drop-down list.
   Server Profile	Select Duo RADIUS from the drop-down list (or whatever name used to create the RADIUS Server Profile in the Add the Duo RADIUS Server section.

3. Click OK to save the authentication profile.

   

Configure GlobalProtect Gateway

1. On the Network tab, navigate to GlobalProtect then Gateways.
2. Click on your configured GlobalProtect Gateway to bring up the properties window.
3. In the Authentication section of the GlobalProtect Gateway General properties tab, select the Duo authentication profile created in Add an Authentication Profile from the drop-down list.

4. Click OK to save the GlobalProtect Gateway settings.

   

Configure GlobalProtect Portal

If the GlobalProtect Portal is configured for Duo two-factor authentication, users may have to authenticate twice when connecting the GlobalProtect Gateway Agent. For the best user experience, Duo recommends leaving your GlobalProtect Portal set to use LDAP or Kerberos authentication.

If your organization would like to protect the GlobalProtect Portals with Duo follow these instructions.

1. On the Network tab, navigate to GlobalProtect then Portal.
2. Click on your configured GlobalProtect Portal to bring up the properties window.
3. In the Authentication section of the GlobalProtect Portal Portal Configuration properties tab, select the Duo authentication profile created in Add an Authentication Profile from the drop-down list.

4. Click OK to save the GlobalProtect Portal settings.

   

Commit and Save Your Settings

To make your changes take effect, click the Commit button in the upper-right corner of the Palo Alto administrative interface. Once you've tested your setup, you can click Save to save the settings.

Client IP Reporting

When using Duo's radius_server_auto integration with the Palo Alto GlobalProtect Gateway clients or Portal access, Duo's authentication logs may show the endpoint IP as 0.0.0.0. Palo Alto does not send the client IP address using the standard RADIUS attribute Calling-Station-Id.

A new RADIUS attribute containing the client IP address (PaloAlto-Client-Source-IP) was introduced in PAN-OS v7. Duo's Authentication Proxy supports the PaloAlto-Client-Source-IP attribute as of version 2.4.12.

To send the PaloAlto-Client-Source-IP attribute information to Duo:

1. Connect to the PA device administration shell and enable sending the PaloAlto-Client-Source-IP client IP attribute:

   set authentication radius-vsa-on client-source-ip

2. When configuring the Authentication Proxy's [radius_server_auto] authproxy.cfg settings for your Palo Alto device include the following setting:

   client_ip_attr=paloalto

The client IP address is sent to the Authentication Proxy as AVP 19 and is captured in Duo's authentication log.

Test Your Setup

Navigate your browser to the GlobalProtect Portal page, or attempt to connect your GlobalProtect Gateway agent.

To test your setup, attempt to log in to your newly-configured system. 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 our Palo Alto Knowledge Base articles or Community discussions. For further assistance, contact Support.

Network Diagram

1. Primary authentication initiated to Palo Alto Global Protect
2. Palo Alto Global Protect sends 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. Palo Alto Global Protect access granted