SSH disconnects very troubling

[Anne Moore]

Hi All
 
Whenever my users connect to my FreeBSD system, they are automatically
disconnected after 1 minute of inactivity. This happens no matter if they
are connected to our Oracle instance or SSH or Telnet, or anything. It's
like the server "hangs-up" on them after no activity for a minute or so.
 
I ran tcpdump during and received this error on the disconnect:
 
17:20:21.362159 IP 192.168.8.90.56141 > myhost1.rdm.loc.ssh: . ack 233 win
33303 <nop,nop,timestamp 2469825 98100123>
 
I'm stumped! Does anyone have any idea why this might be happening?
 
Thank you for your help! 
 
Anne