How to set default session timeout in Linux

posted on March 5, 2008 in HowTo, Linux with 11 Comments

My DC operation guys access Linux servers on a daily basis but somehow they never remember to log out. This is a security risk as anyone could gain access to the open console and create caos.

Today, yet again I’m forced to play the bad guy by dummy proofing my Linux servers by implementing default timeout for user sessions.

Bash and Korn both support the TMOUT variable which I will use to set the default timeout.

The etc/.bashrc file will apply the timeout system wide but if you need it to be user specific then modify the ~/.bashrc file instead.

Here’s how it’s done.

echo "TMOUT=300 &gt;&gt; /etc/bashrc

1	echo "TMOUT=300 >> /etc/bashrc

echo "readonly TMOUT" &gt;&gt; /etc/bashrc

1	echo "readonly TMOUT" >> /etc/bashrc

echo "export TMOUT" &gt;&gt; /etc/bashrc

1	echo "export TMOUT" >> /etc/bashrc

Log off, start a new session and wait for 5 minutes. Your session should terminate

Manojg

This is helpful. what is the equivalent variable for c shell? I connect to the remote computer via ssh and I am being log out after certain time if I stop working. I checked the /etc/bashrc and /etc/csh.cshrc files in remote computer, and ~.bashrc and ~.cshrc files in my local computer but I could not find anything about the log out time. Where is this log out time hidden?

Thanks.
Shrirang

Danesh,

Does the soultion work if someone enables the keepalive configuration in the client application (like putty)? It will not, since the client will keep sending null packets to the server, so it will never seem like the client is idle.

Thanks,

Shrirang.
Chris

If you’re running debian check out timeoutd. Not sure if it will solve all your issues but it sure is nice to have that in one place.
vaibhav

Is it possible to set different timeouts for different users?

I mean I do not want user1 to be idle for more than, say, 5 minutes, but it is alright if user2 stays idle for an hour or so.

Is it possible to execute it?
Danesh

vaibhav, you could try adding the above into the .bashrc file within your user’s user dir.

Tell me if it works
LinuxM@n

Thanks for posting the timeout instructions. I work with Ubuntu 10.04 and the 3 lines of code does in fact disconnect my user.

I modified the .bashrc file in the home directory.

Thanks!
sunili

good one .. thanks
Pingback: How to keep your Linux session alive()
Alex Matskoff

Hi,
Will it work if something like htop or dstat is running? From what I remember it should not.
- Curt Sampson
  
  No, it will not.
Curt Sampson

Note that this works only in bash, and when bash itself is waiting for input. If someone leaves a session running an editor, for example, it will never timeout. Also, the TMOUT variable doesn’t carry across a sudo command in many configurations.

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How to set default session timeout in Linux

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