If user login and don't do anything in 15 mins, the user is kicked off from the server. how to disable it?
This is due to the TMOUT variable which is most likely set in /etc/profile.
Thank you, however, when I check /etc/profile, and .profile for user, there are not TMOUT or TIMEOUT setup.
Who knows there is other place to setup?
Such a function could also be implemented by a firewall.
It could very well be a firewall setting. However give this a try to at least eliminate the possibilty of the TMOUT variable. Login as the user and run "echo $TMOUT" and see if it returns anything.
As a quick solution, do
$ TMOUT=
After you log in
Or add this into your .profile