UDP-Bridge is a transparent proxy for UDP traffic, designed for use with Linux 2.2.x kernels. It provides two-way proxying of UDP packets, to avoid the port number mangling that occurs with Linux IP masquerading. This mangle rule causes problems for some online games.
This program was actually developed to solve a problem with handling Playstation 2 network traffic through a Linux firewall. According to testimonials, most games worked fine with this kind of configuration, but the one that I had tried (ATV Offroad Fury 2) would not work. The problem was apparently the UDP port mangling done by Linux IP masquerading, hence the need for this proxy.
To build the proxy, simply run make from within the source directory:
To install the proxy, run the following command as root:
This will install the proxy executable (udpbridge) into /usr/local/sbin, and the man page into /usr/local/man/man8.
The last step is to create and install a configuration file. The included example.conf file is a good template for this. The default location for the configuration file is /etc/udpbridge.conf.