Which command is best for viewing the health and state of routing and interface on FortiGate?

The command that is optimal for viewing the health and state of routing and interface on a FortiGate device is "get router info kernel." This command provides comprehensive information about the routing details and the status of interfaces, including various kernel-specific routing metrics, which are crucial for diagnosing network connectivity and performance issues.

When executed, this command retrieves valuable data such as the routing table and state of the routes processed by the kernel. It can also display statistics that help network administrators understand how routes are being utilized and whether any issues may be affecting them.

Other options, while potentially useful in specific scenarios, do not offer the same depth of information regarding routing and interface health. For instance, "diagnose health check" is often used to assess the status of health checks associated with links or servers, rather than providing a broad view of routing and interface health. "Get system status" displays general system information, not specifically focused on routing and interfaces. Finally, "show routing interface" typically would present interface-specific details, but may not give the full routing information that a kernel-level command would. Thus, for a detailed overview of routing and interface health, the "get router info kernel" command is the most effective choice.