Set Up Kerberos Authentication

1. Create a server profile.
   The server profile identifies the external authentication service and instructs the firewall on how to connect to that authentication service and access the authentication credentials for your users.
   1. Select DeviceServer ProfilesKerberos, and then Add a Kerberos server profile.
   2. Enter a Profile Name, such as GP-User-Auth.
   3. If this profile is for a firewall with multiple virtual systems capability, select a virtual system or Shared as the Location where the profile is available.
   4. Click Add in the Servers area, and then enter the following information for connecting to the authentication server:
      • Server Name
      • IP address or FQDN of the Kerberos Server
      • Port
   5. Click OK to save the server profile.
2. (Optional) Create an authentication profile.
   The authentication profile specifies the server profile that the portal or gateways use when they authenticate users. On a portal or gateway, you can assign one or more authentication profiles in one or more client authentication profile. For information on how an authentication profile within a client authentication profile supports granular user authentication, see Configure a GlobalProtect Gateway and Set Up Access to the GlobalProtect Portal.

   To enable users to connect and change their expired passwords without administrative intervention, consider using Remote Access VPN with Pre-Logon.
   1. Select DeviceAuthentication Profile, and then Add a new profile.
   2. Enter a Name for the profile, and then select Kerberos as the authentication Type.
   3. Select the Kerberos authentication Server Profile that you created in step 1.
   4. Specify the User Domain and Username Modifier. The endpoint combines these values to modify the domain/username string that a user enters during login. The endpoint uses the modified string for authentication and the User Domain value for User-ID group mapping. Modifying user inputs is useful when the authentication service requires domain/username strings in a particular format but you do not want to rely on users entering the domain correctly. You can select from the following options:
      • To send the unmodified user input, leave the User Domain blank (default) and set the Username Modifier to the variable %USERINPUT% (default).
      • To prepend a domain to the user input, enter a User Domain and set the Username Modifier to %USERDOMAIN%\%USERINPUT%.
      • To append a domain to the user input, enter a User Domain and set the Username Modifier to %USERINPUT%@%USERDOMAIN%.

      If the Username Modifier includes the %USERDOMAIN% variable, the User Domain value replaces any domain string that the user enters. If the User Domain is blank, the device removes any user-entered domain string.
   5. Configure Kerberos single sign-on (SSO) if your network supports it.
      • Enter the Kerberos Realm (up to 127 characters) to specify the hostname portion of the user login name. For example, the user account name user@EXAMPLE.LOCAL has the realm EXAMPLE.LOCAL.
      • Import a Kerberos Keytab file. When prompted, Browse for the keytab file, and then click OK. During authentication, the endpoint first attempts to establish SSO using the keytab. If it is successful, and the user attempting access is in the Allow List, authentication succeeds immediately. Otherwise, the authentication process falls back to manual (username/password) authentication using the specified authentication Type. The Type does not have to be Kerberos. To change this behavior so users can authenticate using only Kerberos, set Use Default Authentication on Kerberos Authentication Failure to No in the GlobalProtect portal agent configuration.
   6. On the Advanced tab, Add an Allow List to select the users and user groups that are allowed to authenticate with this profile. The all option allows every user to authenticate with this profile. By default, the list has no entries, which means no users can authenticate.
   7. Click OK.
3. Commit the configuration.
   Click Commit.