What command is essential for enabling detailed BGP session logging?

The command that enables detailed BGP session logging is crucial for network administrators who want to monitor and troubleshoot BGP sessions effectively. When you execute the command "diagnose ip router bgp all enable," it instructs the FortiGate device to log all BGP-related activity, providing granular insights into BGP sessions, including establishment, maintenance, and potential issues.

This command is particularly useful for diagnosing BGP-related problems, as it captures detailed information about the state of the BGP sessions, the routes exchanged, and any errors that may arise. This logging helps network engineers identify misconfigurations, connectivity issues, or problems with route propagation.

Other commands listed do not serve the specific purpose of enabling detailed BGP session logging. For instance, enabling debugging with "diagnose debug enable" generally affects broader debugging capabilities across various protocols, not targeted specifically at BGP. Similarly, commands related to system configuration or execution of BGP clearing do not provide the detailed log output required for analyzing BGP sessions. Thus, the selection of the command that directly pertains to BGP logging is essential for effective network management and troubleshooting.