TCP/IP / UDP/IP connection proxy

Are you behind a disturbing firewall, that does not allow you to run any public services for the Internet?

Do you have access to a non-firewalled computer somewhere? Can you connect to it with ssh? If you can, connproxy will solve the rest of your problems.

connproxy consists of two programs: connmaster and connbeacon. Connmaster is run on your computer, and connbeacon is run on the non-firewalled computer. The programs will talk to each others, and connbeacon starts receiving connections. The connection between connbeacon and connmaster will work as a wormhole which makes the Internet behind your firewall able to reach your computer.

Example of use:

twinpipe "connmaster -t6667:22" "ssh 10.104.2.2 connbeacon"
(Tunnels tcp port 6667 of 10.104.2.2 to local 22)

(Note you could also do this with ssh alone without connproxy:
ssh -R6667:localhost:22 10.104.2.2)

But -- you can not forward UDP ports with ssh:
twinpipe "connmaster -u4665" "ssh 10.104.2.2 connbeacon"

You will also need the twinpipe program, which connects the stdins and stdouts of the master and beacon program together.
A working version of twinpipe is included in the package, so you don't need a separate download.

Note that you do not actually need ssh. Any way you can make the beacon and master communicate with each other (one's stdin becomes other's stdout) will work.

You can masquerade multiple tcp and udp ports with just the one wormhole.

tcp-to-udp or udp-to-tcp conversions are theoretically possible, but not implemented due to unapplicability.

connproxy has been written by Joel Yliluoma, a.k.a. Bisqwit,
and is distributed under the terms of the General Public License (GPL).

• Anything-over-http support (http is usually the least firewalled service)
• Implicit connection
• Manual pages
• Invent a way to not lose the information about connectee (kernel-level stuff, sorry)
• Gatewaying of outgoing connections also (eeh, this is ppp/vpn stuff already)
• Intense testing of udp forwarding. It has actually not been tested yet.
• Invent something wise to replace the thousand FIXME-comments in system call error checking.

connproxy has been written in C++.
GNU make is required.
The poll system call is also required. This may or may not cause problems on *BSD systems.
connproxy compiles without warnings at least on g++ versions 2.95.2, 3.0.1 and 3.0.3 in Linux.
The protocol and structure of connproxy are system independent. The master and beacon ends of the wormhole don't need to have the same operating system or hardware architechture.

The official home page of connproxy is at http://oktober.stc.cx/source/connproxy.html.
Check there for new versions.