We had noticed that idle-timeout would work on our systems... *only* if the
timeout was set for a very short amount of time... like a minute or so.
....but, if the idle-timeout was set to 20 or 30 minutes... idle-timeout
would *never* work.
So, we finally figured out what was happening.... our Windows 95
clients Network Neighborhood was browsing the network automatically
every 12 minutes or so.... which was generating activity... which was
nullifying the idle-timeout feature.
If you remove everything out of the Network configuration, except the
Dial-Up Adapter and TCP/IP... it works great.
Hope this helps someone with a similiar problem...