CSDoom

From ZDoom Wiki

CSDoom, or 'Client/Server Doom', is a network port based on the Zdoom 1.22 official release. The Client/Server architecture generally provides a more enjoyable on-line experience than the peer-to-peer design native to ZDoom--especially in games involving three or more players. Though CSDoom does not include many of the schnazzy features present in ZDaemon, or Skulltag, it is one very playable option for on-line play.

The original version of CSDoom, by Sergey Makovkin, is no longer being maintained, and the latest version is 0.7. Voxelsoft has decided to continue working on the port, however, and has released a new version as of September 24, 2004.