I just found the PC version of halo at superstore allowing me to play online and what do i find when i go looking for patches on filefront but halo CE. You need Halo installed (i think) and the Halo disk but once you install the two hour download (and yes it is a legal download) and install CE you now have a version of halo solely for multipayer.
You can mod it and give custom maps to i recommend it to anyone who has the PC version of halo
I also recomend the mod Halo CMT this adds halo’s campaign to halo CE with a twist the game has better graphics and a bunch of halo 2 weapons > > plus much more
edit: CMT is evil the mode easy is like the mode elite in difficulty at least i shudder to think what legendary will be like