>...It is common for firewall software to have its own "idletimeout" value. ...
As always, excellent experience-based info from Wanda. You might also look into the possibility of tuning the TCP keepalive value for the client operating system. For example, AIX has a network tuning option called tcp_keepintvl, which defaults to 75 seconds. Note that the client programming might also set the SO_KEEPALIVE socket option. Richard Sims