oracle database connection timed out

we noticed that if our user used vpn connection to connect to oracl database, the client will get timed out if the session is idle for some time around 10-15 mins.

is there any settings that we can configure to prevent the idle connection from getting disconnected ???

we tested using forticlient to connect to our database servers and then leave the session open, it will get disconnect after some time.

user need to re-login again

my fortigate is FG300D and firmware 5.2.3