For IBM RS/6000

To display the current timeout value, enter:

/usr/sbin/no -o tcp_keepidle

The tcp_keepidle parameter specifies the length of time (measured in half seconds) to keep an idle connection active before the system checks to see if the connection died. The default is 14,400 half seconds (7200 seconds, or 2 hours).

IBM recommends a value of at least 15 minutes.