Errata
WANProxy is presently considered beta software at best. Though it has been under development for some time now and has seen extensive testing, that testing has been in limited environments. The issues enumerated here tend to be major issues that are outstanding. An accounting of minor problems and problems which have been fixed will appear after version 1.0.
WANProxy is a fairly simple program at present and does not support many key features which are necessary to build a production-deployable proxy, including persistent storage of previously sent data.
Protocol support for exchanging previously-sent data is currently very new and may not work completely. When you restart one half of a proxy, you may need to restart both. This also means that problems may occur when dealing with multiple clients.
There is also no way to resolve ambiguity in collisions between clients and servers, or between two clients using the same server, etc.
Because no authentication is currently performed between WANProxy instances, an attacker with knowledge of the WANProxy protocol could attempt to guess the symbolic identifiers that WANProxy uses to refer to previously-sent data to discover sensitive information. This will be fixed in the future.
No limits on buffering are currently set meaning that the WANProxy program can take a lot of memory for a large transfer, and that there may be a lack of backpressure on both sides of a proxy.