Finally, there’s a working patch available for Red Alert 2 that transforms the game to utilise the UDP protocol on LAN instead of IPX (which is no longer supported on Microsoft Windows Vista). The patch requires the modified file,
wsock32.dll, to be moved into the root folder of the game. I can hazard a guess that the author of the patch ingeniously hacked the DLL file and overwrote the network routines to use UDP, and since the DLL is available in the same folder as the game binary, it is loaded instead of the original DLL.
I use the patch on Microsoft Windows Vista Home Basic to play Red Alert 2 with a friend on Microsoft Windows XP. He, too, has the patch deployed. Give or take a few not too bothersome glitches sometimes, the game works flawlessly. In our configuration, both the players have the patch deployed. I cannot vouch for whether a mix of UPD and IPX game clients will work.