Comprehensive and Detailed Explanation From Palo Alto Networks Next-Generation Firewall Engineer documents objectives:
According to Palo Alto Networks technical documentation,GlobalProtectis considered the most accurate and preferred method for obtaining user-to-IP address mappings. This is because GlobalProtect requires an explicit authentication event directly with the firewall (or portal/gateway) to establish a connection. Whether the user is internal or external, the GlobalProtect app provides the firewall with consistent, high-fidelity identity data the moment the network interface is initialized.
While the Authentication Portal (formerly Captive Portal) also uses direct authentication, it is often triggered by specific web traffic (HTTP/HTTPS) and is generally used as a fallback for users who cannot be identified through other means. GlobalProtect, conversely, is described as the "best solution" for sensitive environments because it ensures that the mapping is established at the session level and remains persistent as long as the agent is connected. It eliminates the latency and "best-guess" nature of passive methods like Server Monitoring (probing Active Directory logs) or XFF headers, which can be spoofed or stripped by proxies.
Because the firewall itself validates the credentials and maintains the tunnel or connection state, the resulting mapping is 100% verified and tied to the specific device's logical interface.