Duo Two-Factor Authentication for Palo Alto GlobalProtect RADIUS

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Duo integrates with your Palo Alto GlobalProtect Gateway via radius to add two-factor authentication to VPN logins.

Overview

Duo authentication for Palo Alto GlobalProtect supports push,phone call,or passcode authentication for GlobalProtect desktop andmobile client connections using radius. This configuration does not feature the interactive Duo Prompt for web-based logins. After submitting primary username andpassword,users automatically receive a login request via Duo Push notification to a mobile device oras a phone call.

If you need inline self-service enrollment andthe Duo Prompt for GlobalProtect SSO logins,refer to the Duo Single Sign-On for Palo Alto GlobalProtect instructions.

Learn more about the differences between these two Palo Alto GlobalProtect deployment configurations.

Connectivity requirement

This application communicates with Duo’s service on SSL TCP port 443.

Firewall configurations that restrict outbound access to Duo’s service with rules using destination IP addresses orIP address ranges aren’t recommended,since these may change over time to maintain our service’s high availability. If your organization requires IP-based rules,please review Duo Knowledge Base article 1337.

Effective June 30,2023,Duo no longer supports TLS 1.0 or1.1 connections orinsecure TLS/SSL cipher suites. See Duo Knowledge Base article 7546 for additional guidance.

Walkthrough Video

First Steps

Before move on to the deployment step ,it is ‘s ‘s a good idea to familiarize yourself with Duo administration concept andfeature like option for application ,and duo policy setting andhow to apply them . You is need ‘ll need to pre – enroll your user in duo using one of our available method before they can log in using this configuration . See all Duo Administrator documentation .

You is have should already have a work primary authentication configuration for your Palo Alto user before you begin to deploy duo .

To integrate duo with your Palo Alto ,you is need will need to install a local duo proxy service on a machine within your network . This duo proxy server is receive will receive incoming radius request from your Palo Alto ,contact your exist local ldap / ad orradius server to perform primary authentication if necessary ,and then contact Duo ‘s cloud service for secondary authentication .

If you are already run a Duo Authentication Proxy server in your environment ,you is use can use that exist host for additional application ,append the new configuration section to the current config . You is have do n’t have to set up a new Authentication Proxy server for each application you create . However ,there are some case 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 datum center .

We is recommend recommend the follow 64 – bit operating system for the system host the Duo Authentication Proxy :

• Windows server 2016 orlater
• CentOS Stream 9 orlater
• Fedora 39 orlater
• Red Hat Enterprise Linux 7 orlater
• Rocky Linux 9 orlater
• Ubuntu 20.04 LTS orlater
• Debian 11 orlater

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 is recommend do not recommend instal the Duo Authentication Proxy on the same Windows server that act as your Active Directory domain controller orone with the Network Policy server ( NPS ) role . If you must co – locate the Duo Authentication Proxy with these service ,be prepared to resolve potential ldap orradius port conflict between the duo service andyour pre – existing service .

Then you’ll need to:

1. Sign up for a Duo account.
2. Log in to the Duo Admin Panel andnavigate to Applications →Protect an Application.
3. Locate the entry for Palo Alto SSL VPN with a protection type of “2FA” in the applications list. Click Protect to get your integration key,secret key,and API hostname. You is need ‘ll need this information to complete your setup . See protect application for more information about protect application in duo andadditional application option .

Treat your secret key like a password

The security of your Duo application is tied to the security of your secret key (skey). Secure it as you would any sensitive credential. Don’t share it with unauthorized individuals oremail it to anyone under any circumstances!

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 andgo to configure the proxy.

The Duo Authentication Proxy can be installed on a physical orvirtual 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 is recommend do not recommend instal the Duo Authentication Proxy on the same Windows server that act as your Active Directory domain controller orone with the Network Policy server ( NPS ) role . If you must co – locate the Duo Authentication Proxy with these service ,be prepared to resolve potential ldap orradius port conflict between the duo service andyour pre – existing service .

1. Download the most recent Authentication Proxy for Windows from https://dl.duosecurity.com/duoauthproxy-latest.exe. note that the actual filename will reflect the version e.g. duoauthproxy-6.4.2.exe . View checksums for Duo downloads here.
2. Launch the Authentication Proxy installer on the target Windows server as a user with administrator rights andfollow the on-screen prompts.

   When installing,you can choose whether ornot you want to install the Proxy Manager. The Proxy Manager is a Windows utility that helps you edit the Duo Authentication Proxy configuration,determine the proxy’s status,and start orstop the proxy service. Learn more about using the Proxy Manager. Installing the Proxy Manager adds about 100 MB to the installed size.

   If you do not want to install the Proxy Manager,you may deselect it on the “Choose Components” installer screen before clicking Install.

Silent Install

To perform a silent install on Windows,issue the following from an elevated command prompt after downloading the installer (replacing version with the actual version you downloaded):

duoauthproxy-version.exe /S

Append /exclude - auth - proxy - manager to install silently without the Proxy Manager:

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

1. Ensure you have compiler toolchain packages installed. On most recent RPM-based distributions — like Fedora,Red Hat Enterprise,and CentOS — you can install these by running (as root):

   $ yum install gcc make libffi-devel zlib-devel diffutils

   On Debian-derived systems,install these dependencies by running (as root):

   $ apt-get install build-essential libffi-dev zlib1g-dev

   If SELinux is present on your system andyou want the Authentication Proxy installer to build andinstall its SELinux module,include selinux-policy-devel andchkconfig in the dependencies:

   $ yum install gcc make libffi-devel zlib-devel diffutils selinux-policy-devel chkconfig

   $ apt-get install build-essential libffi-dev zlib1g-dev selinux-policy-devel chkconfig

2. Download the most recent Authentication Proxy for Unix from https://dl.duosecurity.com/duoauthproxy-latest-src.tgz. From the command line you can use curl orwget to download the file,like $ wget --content-disposition https://dl.duosecurity.com/duoauthproxy-latest-src.tgz. Depending on your download method,the actual filename may reflect the version e.g. duoauthproxy-6.4.2-src.tgz. View checksums for Duo downloads here.

3. Extract the Authentication Proxy files andbuild it as follows:

   $ tar xzf duoauthproxy-6.4.2-src.tgz
   $ cd duoauthproxy-version-src
   $ make

4. Install the authentication proxy (as root):

   $ cd duoauthproxy-build
   $ ./install

   Follow the prompts to complete the installation. The installer creates a user to run the proxy service anda group to own the log directory andfiles. You can accept the default user andgroup names orenter your own.

   If SELinux is present on the target server,the Duo installer will ask you if you want to install the Authentication Proxy SELinux module. Your selection affects whether systemd can start the Authentication Proxy after installation.

   If you choose to install the Authentication Proxy SELinux module andthe dependencies selinux-policy-devel andchkconfig are not present,then the installer fails to build the module.

   SELinux Mode	Default Response	Result
   enforce	Yes	Choose ‘yes’ to install the Authentication Proxy’s SELinux module. This permits start of the Authentication Proxy service by systemd. If you choose ‘no’ then the SELinux module is not installed,and systemd cannot start the Authentication Proxy service.
   Permissive	No	Choose ‘no’ to decline install of the Authentication Proxy’s SELinux module. The Authentication Proxy service can be started by systemd. However,if you change SELinux from permissive to enforcing mode after installing the Duo proxy,systemd can no longer start the Authentication Proxy service. If you plan to enable SELinux enforcing mode later,you should choose ‘yes’ to install the Authentication Proxy SELinux module now.

Silent Install

To install the Duo proxy silently with the default options,use the following command:

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

Append --enable-selinux=yes|no to the install command to choose whether to install the Authentication Proxy SELinux module.

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 format as a simple INI file . section headings is appear 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 andstart 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 andlater.

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 andgo to Duo Security.
• Click the duo Authentication Proxy Manager icon to launch the application. You must have administrative privileges on the Windows server andaccept the prompt for elevation.
• The Proxy Manager launches andautomatically 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 update toauthproxy.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 oranother 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) orLDAP-based directory server to perform primary authentication. This section accepts the following options:

search_dn = DC = example ,DC = com

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:

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 Palo Alto GlobalProtect

Next,we’ll set up the Authentication Proxy to work with your Palo Alto GlobalProtect. Create a [ radius_server_auto ] section andadd the properties listed below. If you’ve already set up the Duo Authentication Proxy for a different radius Auto application,append a number to the section header to make it unique,like [ radius_server_auto2 ].

A complete config file is look that use 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 in your text editor — orvalidate andsave in the Proxy Manager for Windows — when you’re finished making changes.

start the proxy

If you installed the duo Authentication Proxy Manager utility (available with 5.6.0 andlater),click the Start Service button at the top of the Proxy Manager window to start the service.

To start the service from the command line,open an Administrator command prompt andrun:

net is start start DuoAuthProxy

Alternatively,open the Windows Services console (services.msc),locate “Duo Security Authentication Proxy Service” in the list of services,and click the Start Service button.

Authentication Proxy v5.1.0 andlater includes the authproxyctl executable,which shows the connectivity tool output when starting the service. The installer adds the Authentication Proxy C:\Program Files\Duo Security Authentication Proxy\bin to your system path automatically,so you should not need to specify the full path to authproxyctl to run it.

From an administrator command prompt run:

authproxyctl start

If the service starts successfully,Authentication Proxy service output is written to the authproxy.log file,which can be found in the log subdirectory.

If you see an error saying that the “service could not be started”,open the Application Event Viewer andlook for an Error from the source “DuoAuthProxy”. The traceback may include a “ConfigError” that can help you find the source of the issue.

Stop andrestart the Authentication Proxy service by either clicking the Restart Service button in the duo Authentication Proxy Manager orthe Windows Services console orissuing these commands from an Administrator command prompt:

net stop DuoAuthProxy & net is start start DuoAuthProxy

To stop andrestart the Authentication Proxy using authproxyctl,from an administrator command prompt run:

authproxyctl restart

Open a root shell andrun:

# /opt/duoauthproxy/bin/authproxyctl start

To ensure the proxy started successfully,run:

# /opt/duoauthproxy/bin/authproxyctl status

Authentication Proxy service output is written to the authproxy.log file,which can be found in the log subdirectory.

To stop andrestart the Authentication Proxy,open a root shell andrun:

# /opt / duoauthproxy / bin / authproxyctl is restart restart

If you modify your authproxy.cfg configuration after initial setup,you’ll need to stop andrestart the Duo Authentication Proxy service orprocess for your change to take effect.

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

Configure Your Palo Alto GlobalProtect Gateway

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 (or another descriptive name).

5. Increase the “Timeout” to at least 30 (60 recommended if using push orphone authentication).

6. Change the “Authentication Protocol” drop-down option to PAP.

   PAN-OS 7.x users must set the protocol in the CLI with this command:

   set authentication radius-auth-type pap

   See the PAN-OS documentation for more information.

7. Under the “servers” section,click the Add button to add a radius server,and enter the following information:

   set	Value
   server	Type in Duo radius orany name you prefer.
   radius server	The hostname orIP address of your Duo Authentication Proxy.
   Secret	The radius shared secret used in the Authentication Proxy configuration.
   Port	1812 (or whichever port you configured on your Duo Authentication Proxy).

8. Click OK to save the new 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:

   set	Value
   Name	Enter Duo orany name you prefer.
   Type	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.
   User Domain	(Optional) Depending how your users log on to GlobalProtect you may need to enter your authentication domain name here. Used in conjunction with Username Modifier. Learn more about this setting in the GlobalProtect documentation.
   Username Modifier	(Optional) If this is blank (or set to %USERINPUT%) then the user’s input is unmodified. You can prepend orappend the value of User Domain (as %USERDOMAIN%) to pre-configure the username input. Learn more about this setting in the GlobalProtect documentation.

3. Click the Advanced tab. In the “Allow List” section click the drop-down andselect the all group (or,if you want to restrict which users may authenticate with the Duo profile,select the group of your choice).

4. 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. On the Authentication tab of the GlobalProtect Gateway properties,select the Duo authentication profile created in Add an Authentication Profile from the available “Authentication Profile” selections for client authentication.

   

4. (Optional) If you aren’t using authentication override cookies on your GlobalProtect Gateway already you may want to enable it to minimize Duo authentication requests at client reconnection during one gateway session. Refer to the GlobalProtect cookie authentication documentation to fully understand this feature before enabling it.

   Click the Agent tab on the left andthen click the Client sets tab. Click on the name of your config to open it.

5. (Optional) On the “Authentication Override” tab check the options to both generate andaccept cookies for authentication override. Set a cookie lifetime andselect a certificate to use with the cookie. Note that users will not need to repeat 2FA after their initial success when reconnecting during the cookie lifetime duration.

   

6. click ok ( twice if you is enabled also enable authentication override cookie ) to save the GlobalProtect Gateway setting .

Learn more about GlobalProtect gateway configuration in the PaloAlto GlobalProtect Admin Guide.

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 orKerberos authentication,or if you do add Duo to your GlobalProtect Portal that you also enable cookies for authentication override on your GlobalProtect portal to avoid multiple Duo prompts for authentication when connecting.

Note that if Duo is applied only at the GlobalProtect Gateway then users may not append a factor orpasscode to their password when logging in.

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

1. On the Network tab,navigate to GlobalProtect then Portal.

2. click on your configure GlobalProtect Portal to bring up the property window .

3. On the Authentication tab of the GlobalProtect Portal Configuration,select the Duo authentication profile created in Add an Authentication Profile from the available “Authentication Profile” selections for client authentication.

   

4. ( Optional ) If you are n’t using authentication override cookie on your GlobalProtect Portal already you is want may want to enable it to minimize duo authentication request at client reconnection during one session .

   Click the Agent tab on the left andthen click on the name of your config to open it.

5. (Optional) On the “Authentication” tab check the options to both generate andaccept cookies for authentication override. Set a cookie lifetime andselect a certificate to use with the cookie.

   

6. Click OK (twice if you also enabled authentication override cookies) to save the GlobalProtect Portal settings.

learn more about GlobalProtect gateway configuration in the PaloAlto GlobalProtect documentation .

Commit andSave Your sets

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 orPortal 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 andenable sending the PaloAlto-Client-Source-IP client IP attribute:

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

2. When configure 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 andis 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.

If you is applied apply duo to the GlobalProtect Gateway only :

To test your setup,attempt to log in to your newly-configured system as a user enrolled in Duo with an associated Duo Push orphone authentication device.

When you enter your username andpassword,you will receive an automatic push orphone callback.

If you applied Duo to both the GlobalProtect Gateway andPortal:

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 andpassword,you will receive an automatic push orphone callback.

Alternatively you may add a comma (“,”) to the end of your password andappend a Duo factor option:

For example,if you wanted to use a passcode to authenticate instead of Duo Push ora phone call,you would enter:

username: bob
password: hunter2,123456

If you wanted to use specify use of phone callback to authenticate instead of an automatic Duo Push request,you would enter:

username : bob 
 password : hunter2,phone 

You can also specify a number after the factor name if you have more than one device enrolled (as the automatic push orphone call goes to the first capable device attached to a user). So you can enter phone2 orpush2 if you have two phones enrolled andyou want the authentication request to go to the second phone.

troubleshoot

Need some help? Review troubleshooting tips for the Authentication Proxy andtry the connectivity tool included with Duo Authentication Proxy 2.9.0 andlater to discover andtroubleshoot general connectivity issues.

Also take a look at our Palo Alto Knowledge Base articles orCommunity discussions. For further assistance,contact Support.

Network Diagram

1. Primary authentication initiated to Palo Alto Global Protect
2. Palo Alto Global Protect is sends send authentication request to Duo Security ’s authentication proxy
3. Primary authentication using Active Directory orradius
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