Examine the following CLI configuration: config system session-ttl set default 1800 end What statement is true about the effect of the above configuration line?

The `config system session-ttl set default 1800` command configures the global default idle timeout for all new sessions passing through the FortiGate, meaning that if a session remains inactive for 1800 seconds (30 minutes), it will be automatically terminated.

This command sets the *idle* timeout, not the absolute maximum length of time a session can be open; active sessions will reset their idle timer.

The `session-ttl` command manages session state termination based on inactivity, not user re-authentication; re-authentication is typically governed by authentication policies or timeouts.

FortiGate session-ttl refers to the session's idle timeout, and the device does not automatically send keepalive packets to prolong sessions based on this setting.