This question tests knowledge of Palo Alto Networks User-ID technologies for mapping IP addresses to users.

• Server monitoring is used to gather user mapping information by reading security event logs from servers like Microsoft Domain Controllers or Microsoft Exchange servers.
• The User-ID agent can parse syslog messages sent from a variety of network devices, including Linux/UNIX systems, to identify user login and logout events.
• Client probing is a technique used for Windows clients in environments that do not have a domain controller. The firewall or User-ID agent probes the clients directly to determine the logged-in user.
• The Terminal Services agent is specifically designed for multi-user environments like Citrix or Microsoft Remote Desktop Services, where multiple users share a single IP address. It maps users to specific TCP/UDP port ranges to differentiate their traffic.

Palo Alto Networks, PAN-OS® Administrator's Guide 10.2

Server Monitoring for Microsoft Exchange: "The User-ID agent can monitor Microsoft Exchange servers to map usernames to the IP addresses of client systems." (Refer to section "Configure the User-ID Agent for Server Monitoring").

Syslog Monitoring for Linux: "You can configure the User-ID agent to parse syslog messages received from a syslog sender... Common use cases include collecting user mappings from UNIX/Linux hosts..." (Refer to section "Configure the User-ID Agent to Monitor a Syslog Sender for User Mappings").

Client Probing: "For environments where users are not authenticating to a domain controller...you can enable the User-ID agent to probe client systems in the specified subnets..." (Refer to section "Configure Client Probing").

Terminal Services Agent for Citrix: "To enforce user-based policy rules in a terminal server environment (Citrix or Microsoft Terminal Services)...you must install the Palo Alto Networks Terminal Server (TS) agent on each server." (Refer to section "Enable User-ID for a Terminal Server").