I have run into many cases where my customers had a hard time with a remote
desktop connection to their server disconnecting.
I did all the tweaks needed to make sure terminal services and remote desktop (They are the same) didn't have a timeout limit.
So why on earth was their connections still dropping?
Well after doing some research the problem is the connection being dropped by
the isp or router. When a port is in use but no traffic is going across it the
connection is dropped after a while.
The fix? To have the remote connection send a keep alive, or heart beat packet.
Now the remote desktop will send data to keep the connection alive. And so far, every customer who had disconnect problems has been fixed :-)
I applied this registry tweak to the server the users where connecting to.
Windows Registry Editor Version 5.00