automatic logout

[Bill Tangren]

I am required to configure my servers so that anyone who logs in via ssh or sftp
will be logged out after 30 minutes of inactivity. I have looked through the
openssh documentation and have seen nothing on how do to this 
(ClientAliveInterval doesn't seem to do this). Googling didn't help much either. 
I found an environment variable for the bash and ksh shells that I can put in 
/etc/profile:

# export TMOUT=<timeout_in_seconds>

and this works, but it unceremoniously dumps the connection. And, if you are
logged in to the gui at the console, and you have terminal windows open (not
using ssh) it will close those too. Again with no warning.

Does anyone have any suggestions?

Bill Tangren