For explicit Web Proxy deployment on PAN-OS, Palo Alto Networks currently supports Kerberos and SAML as authentication methods. RADIUS is not supported for explicit or transparent Web Proxy authentication on Palo Alto Networks appliances, which means that if the client is currently using RADIUS, they will need to configure an alternate supported authentication method. LDAP or TACACS+ authentication is not directly supported for Web Proxy authentication in PAN-OS.

For more information on supported Web Proxy authentication methods, please refer to the latest Palo Alto Networks "PAN-OS® Web Interface Reference Guide".