Telnet timout question

ok here is a little bit on what I am trying to do. I am logged into a saolaris 9 server and telnet to another server to run an application that sits on the second unix / linux server. This application can sit idle for an hour to two and any given time. During this time the telnet session timesout and the users have to relog in. Now granted most of us would just login again but the users are at remote locations and never had this issues until we moved the servers off the local network. We have checked all our firewalls, switches and routers and there not booting the connection. Now if I have one of them use putty or secureCRT with anti-idle settings going they don't timeout. The problem is not all locations have a windows box to install those applications they use standard telnet from a unix terminal. My question is after reading a bunch of stuff is how do I send a nop or NO-OP from a standard telnet term on a unix box? Any help would be great on this or if you know another way I am all ears.

Thanks

There is an environment variable called TMOUT that contains the default number of seconds before a shell timeout occurs. If your session is idle for that duration, you get booted. You can however, over ride this variable (assuming that your local sys admin did not make this a read only variable). To do so in Korn Shell:

export TMOUT=0

I have already made that change in the /etc/profile with no luck as the session still times out after an hour. Any other idea's on how to keep this session from a time out. The bad part is that when they run the app it gives them a menu and they will sit there for hours befor ethey imput things.

Check the man page for telnet for your OS - should allow you to break out to show parameters.

What I see from mine: use Control-] to get to telnet prompt -

Then ? to see commands
mine has a send command
Type in send ? and you should see a nop

I also have a problem regarding telnet time out(the server is a p5 520 OS is AIX 5.2):
After telneting to the server, if inactive for more than 20 minutes the session is "closed by foreign host". Where is this timeout value set? I've looked at the /etc/profile and the TMOUT variable is commented out and an echo of TMOUT show a value of 0...which appears to mean "no time out set". We suspect that the new F5 switch is causing the problem, not the OS. Were else can I look?