[gadders]

I'm guessing this is Linux only? My other plan was to create a custom minecraft server on a spare PC.

[WonderfulVoid]

mclanproxy is plain C using Berkeley sockets but uses ip_mreq and getopt which seem to be slightly non-standard. Should work on most Unix/POSIX environments I think, possibly cygwin as well.

[gadders]

I might give Cygwin a go. Anything more complicated than that is beyond me...