Duo integrates with your Palo Alto GlobalProtect Gateway via RADIUS to add two-factor authentication to VPN logins.
Duo authentication for Palo Alto GlobalProtect supports push, phone call, or passcode authentication for GlobalProtect desktop and mobile client connections using RADIUS. This configuration does not feature the interactive Duo Prompt for web-based logins. After submitting primary username and password, users automatically receive a login request via Duo Push notification to a mobile device or as a phone call.
If you need inline self-service enrollment and the Duo Prompt for GlobalProtect SSO logins, refer to the Palo Alto Networks SSO instructions. GlobalProtect SSO requires that you deploy a SAML 2.0 identity provider on your network.
This application communicates with Duo's service on TCP port 443. Firewall configurations that restrict outbound access to Duo's service with rules using destination IP addresses or IP 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 this Duo KB article.
You should already have a working primary authentication configuration for your Palo Alto users before you begin to deploy Duo.
Before proceeding, you should locate (or set up) a system on which you will install the Duo Authentication Proxy. The proxy supports these operating systems:
Then you'll need to:
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 or email it to anyone under any circumstances!
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).
Ensure that Perl, Python 2.6 or 2.7 (including development headers and libraries), and a compiler toolchain are installed. On most recent RPM-based distributions — like Fedora, RedHat Enterprise, and CentOS — you can install these by running (as root):
$ yum install gcc make python-devel libffi-devel perl zlib-devel
On Debian-derived systems, install these dependencies by running (as root):
$ apt-get install build-essential python-dev libffi-dev perl zlib1g-dev
Download the most recent Authentication Proxy for Unix from https://dl.duosecurity.com/duoauthproxy-latest-src.tgz. Depending on your download method, the actual filename may reflect the version e.g. duoauthproxy-3.1.0-src.tgz. View checksums for Duo downloads here.
Extract the Authentication Proxy files and build it as follows:
$ tar xzf duoauthproxy-latest-src.tgz $ cd duoauthproxy-version-src $ make
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 and a group to own the log directory and files. You can accept the default user and group names or enter your own.
If you ever need to uninstall the proxy, run
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:
|Platform||Default Configuration Path|
|Windows (64-bit)||C:\Program Files (x86)\Duo Security Authentication Proxy\conf\authproxy.cfg|
|Windows (32-bit)||C:\Program Files\Duo Security Authentication Proxy\conf\authproxy.cfg|
The configuration file is formatted as a simple INI file. Section headings appear as:
Individual properties beneath a section appear as:
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.
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.
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:
||The hostname or IP address of your domain controller.|
||The username of a domain member account that has permission to bind to your Active Directory and perform searches. We recommend creating a service account that has read-only access.|
The password corresponding to
The LDAP distinguished name (DN) of an Active Directory container or organizational unit (OU) containing all of the users you wish to permit to log in. For example:
The hostname or IP address of a secondary/fallback domain controller. You can add additional domain controllers as
To further restrict access, specify the LDAP distinguished name (DN) of a security group that contains the users who should be able to log in. Other users will not pass primary authentication. For example:
[ad_client] host=184.108.40.206 host_2=220.127.116.11 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.
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:
The IP address of your RADIUS server. You can add backup servers with
||A secret to be shared between the Authentication Proxy and your existing RADIUS server. If you're on Windows and would like to encrypt this secret, see Encrypting Passwords in the full Authentication Proxy documentation.|
The authentication port on your RADIUS server. By default, the proxy will attempt to contact your RADIUS server on port 1812. Use
||If this option is set to "true", all RADIUS attributes set by the primary authentication server will be copied into RADIUS responses sent by the proxy. Default: "false"|
[radius_client] host=18.104.22.168 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.
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:
||Your integration key.|
||Your secret key.|
||Your API hostname (e.g. "api-XXXXXXXX.duosecurity.com").|
||The IP address of your Palo Alto GlobalProtect.|
||A secret to be shared between the proxy and your Palo Alto GlobalProtect. If you're on Windows and would like to encrypt this secret, see Encrypting Passwords in the full Authentication Proxy documentation.|
The mechanism that the Authentication Proxy should use to perform primary authentication. This should correspond with a "client" section elsewhere in the config file.
This parameter is optional if you only have one "client" section. If you have multiple, each "server" section should specify which "client" to use.
||The port on which to listen for incoming RADIUS Access Requests. Default: 1812.|
Either "safe" or "secure":
The IP address of your second Palo Alto GlobalProtect, if you have one. You can specify additional devices as as
The secrets shared with your second Palo Alto GlobalProtect, if using one. You can specify secrets for additional devices as
A completed config file that uses Active Directory should look something like:
[ad_client] host=22.214.171.124 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=126.96.36.199 radius_secret_1=radiussecret1 client=ad_client port=1812 failmode=safe
Make sure to save your configuration file when done.
Open an Administrator command prompt and run:
net 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.
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 and look for an Error from the source "DuoAuthProxy". The traceback may include a "ConfigError" that can help you find the source of the issue.
Stop and restart the Authentication Proxy service by either clicking the Restart Service button in the Windows Services console or issuing these commands from an Administrator command prompt:
net stop DuoAuthProxy & net start DuoAuthProxy
Open a root shell and run:
# /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 and restart the Authentication Proxy, open a root shell and run:
# /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.
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 7.1 documentation for more information.
Under the "Servers" section, click the Add button to add a RADIUS server, and enter the following information:
|Server||Type in Duo RADIUS or any name you prefer.|
|RADIUS Server||The hostname or IP 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).|
Click OK to save the new RADIUS server profile.
Click the New... button to add a new authentication profile, and enter the following information:
|Name||Enter Duo or any 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 or append the value of User Domain (as %USERDOMAIN%) to pre-configure the username input. Learn more about this setting in the GlobalProtect documentation.|
Click the Advanced tab. In the "Allow List" section click the drop-down and select the all group (or, if you want to restrict which users may authenticate with the Duo profile, select the group of your choice).
Click OK to save the authentication profile.
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.
(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 and then click the Client Settings tab. Click on the name of your config to open it.
(Optional) On the "Authentication Override" tab check the options to both generate and accept cookies for authentication override. Set a cookie lifetime and select 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.
Click OK (twice if you also enabled authentication override cookies) to save the GlobalProtect Gateway settings.
Learn more about GlobalProtect gateway configuration in the PaloAlto GlobalProtect Admin Guide.
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, 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.
If your organization would like to protect the GlobalProtect Portal with Duo follow these instructions.
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.
(Optional) If you aren't using authentication override cookies on your GlobalProtect Portal already you may want to enable it to minimize Duo authentication requests at client reconnection during one session.
Click the Agent tab on the left and then click on the name of your config to open it.
(Optional) On the "Authentication" tab check the options to both generate and accept cookies for authentication override. Set a cookie lifetime and select a certificate to use with the cookie.
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.
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.
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:
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
When configuring the Authentication Proxy's
[radius_server_auto] authproxy.cfg settings for your Palo Alto device include the following setting:
The client IP address is sent to the Authentication Proxy as AVP 19 and is captured in Duo's authentication log.
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 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:
Perform Duo Push authentication
You can use Duo Push if you've installed and activate Duo Mobile on your device.
|phone||Perform phone callback authentication.|
Send a new batch of SMS passcodes.
Your authentication attempt will be denied. You can then authenticate with one of the newly-delivered passcodes.
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 (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.