Do you have a current servers.ini file? Many servers on older servers.ini files are no longer active. For that matter, some networks may no longer be active, depending how old your file is.
Other than that, I have no solution for you. Your problem does sound related to port 113 if a particular network requires you to identify with that port rather than letting you on even if you don't identify. As for why it appears to be working backwards in your router, I'm not sure. If you are running multiple computers, are you certain that you are not trying to forward the port to more than one computer?
