The CS 1.6 Zombie server list brings together Zombie Mod, Zombie Plague, and Zombie Escape. Maps beginning with zm_ usually focus on human survival and defense, while ze_ maps are built around escaping the infected. Current player counts, maps, player lists, and IP addresses help you find the mode you want; check each server description for classes, weapons, and abilities.
Zombie Mod replaces the usual team-versus-team setup with humans fighting the infected. Depending on the mode, players defend, try to survive, or reach an evacuation point, while server plugins determine the available classes, abilities, and weapons.