Linux / UNIX Automatically Log BASH / TCSH / SSH Users Out After a Period of Inactivity

My development and testing webserver is used by over 100s of users. These users login from Windows XP, Linux, Mac OS X system via ssh. How do I set or automatically log users out after a period of inactivity under CentOS Linux server to improve server security and save some resources?

You can configure any Linux system to automatically log users out after a period of inactivity. Simply login as the root user and create a file called /etc/profile.d/autologout.sh, enter::

# vi /etc/profile.d/autologout.sh

Append the following code:

TMOUT=300
readonly TMOUT
export TMOUT

Save and close the file. Set permissions:

# chmod +x /etc/profile.d/autologout.sh

Above script will implement a 5 minute idle time-out for the default /bin/bash shell. You can also create tcsh version as follows:

# vi /etc/profile.d/autologout.csh

Append the following code:

set -r autologout 5

Save and close the file. Set permissions, enter:

# chmod +x /etc/profile.d/autologout.csh

Dealing with ssh clients

SSH allows administrators to set an idle timeout interval. After this interval has passed, the idle user will be automatically logged out. Open /etc/ssh/sshd config file, enter:

# vi /etc/ssh/sshd config

Find ClientAliveInterval and set to 300 (5 minutes) as follows:

ClientAliveInterval 300
ClientAliveCountMax 0

Save and close the file. Restart sshd:

# service sshd restart