Terminating idle logins

[john s karabaic]

Anybody know of any daemons that search for users who have been idle
for longer than x minutes and then automatically log them out?  I'm on
a VAXStation III with a 2-user license, so we need something like
this.  I'm also running X Windows, so I may need to hack it so it
won't affect the virtual terminals.
 
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These opinions are mine and I cannot confirm or deny whether anyone else holds 
them.