Is there an auto-logout setting for TELNET

[Gary Yu]

As we know, we can set a time-out or auto-logout for a unattended terminal. I am interested to know if there's a similar setting for telnet service.

the reason for that is: sometime, when I leave a telnet session idle for some time, then it would be logged off by the remote server automatically, I don't know the reason.

Any comment on the breaking of telnet connection is appreciate.

[A. Clay Stephenson · Accepted solution]

Hi,

You simply need to set the the TMOUT variable in the user .profile; the shell will then exit and thus log off a telnet user.

in the user's .profile
export TMOUT=30

to logoff after 30 minutes of inactivity

[James R. Ferguson]

Hi:

Yes, if the shell variable TMOUT is set greater than zero (0). Then, this will cause the shell to terminate if a command is not entered within TMOUT number of seconds after issuing the PS1 prompt.

...JRF...

[Gary Yu]

Thanks guys for your instant reply!

So, in terms of TMOUT, it's the same effect on telnet as with local terminals?

[A. Clay Stephenson]

Hi Gary:

The real answer is that the shell is the same and when it exits the underlying daemon (in this case telnetd) responds.

[Gary Yu]

Thanks Clay, I am clear now :)

[Bill Hassell]

It's important to note that telnet does not have a timeout value, it's the shell you are using. For POSIX and ksh, the value is TMOUT, while for csh, it is autologout and the units of measure are different (seconds versus minutes). Other shells (bash, tcsh and so on) may have similar env values. A useful technique is to set the TMOUT and autologout values with the modifier: readonly as in:

readonly TMOUT=3600

NOTE: not even root can change a readonly env variable in the shell. User timeouts should probably be longer than root (root should have a short, 15-60 minutes).

But most important, the shell does the counting! So if the user starts a subprocess, for example: vi then the counting stops because the shell is not running. When vi terminates, the shell starts counting all over again.

[Brian M. Fisher]

Another "trick" I have seen to avoid the TMOUT setting is to type the backslash character on a blank line. This is a line continuation character that tells the shell there is more information to come.

Brian
<*(((>< er

[sreejith_4]

Hi,

Anyone can please tell me where the autologout variable set. I couldn't find it in .profile.

Thanks
Sreejith M