PortProxy is a TCP connection forwarding service that I wrote in college so that I could run servers from behind a firewall. When I put Linux onto resnet.bryant.edu, I no longer needed this program, but it's still cool if you are running Windows. I also wrote a version that runs as a system tray application in Windows 95.
PortProxy stores its configuration in the
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\PortProxy\Parameters registry key. It can be dynamically configured using a command line interface via a localhost telnet connection to port 256.
When connected to the configuration command line interface, the following commands can be used. Each command is terminated with a newline character. Responses from the server begin with either a plus sign (+) for a positive response or a minus sign (-) for a negative response, similar to DirList Server's protocol.
|+||port intaddr intport 6||Adds a forwarded port
|-||port||Removes a forwarded port
|s||port||Returns whether or not the given local port is being forwarded by PortProxy
|t||port||Tests a local port for use by PortProxy or another application
|n||No operation (no-op)|