Which TCP session timer must be increased to fix this problem?

An administrator has decreased all the TCP session timers to optimize the FortiGate memory usage. However, after the changes, one network application started to have problems. During the troubleshooting, the administrator noticed that the FortiGate deletes the sessions after the clients send the SYN packets, and before the arrival of the SYN/ACKs. When the SYN/ACK packets arrive to the FortiGate, the unit has already deleted the respective sessions.

Which TCP session timer must be increased to fix this problem?
A . TCP half open.
B . TCP half close.
C . TCP time wait.
D . TCP session time to live.

Answer: A

Explanation:

http://docs-legacy.fortinet.com/fos40hlp/43prev/wwhelp/wwhimpl/common/html/wwhelp.htm?context=fgt&file=CLI_get_Commands.58.25.html

The tcp-halfopen-timer controls for how long, after a SYN packet, a session without SYN/ACKremains in the table.

The tcp-halfclose-timer controls for how long, after a FIN packet, a session without FIN/ACKremains in the table.

The tcp-timewait-timer controls for how long, after a FIN/ACK packet, a session remains in thetable. A closed session remains in the session table for a few seconds more to allow any out-of-sequence packet.