Idle time logout mechanism (daemon)

[Harold Cook]

Does anyone have (or know of) a daemon which will monitor users idle time, and 
logout any user idle longer than a given amount of time. We have recently
had troubles with too many people and not enough ports, especially when there
are ports where people have left terminals for extended periods of time.
Please respond via mail and as usual, I will summarize for the net.
Many thanks in advance --