Most modern multiplayer servers use sophisticated to detect this mod:
Practical guidance
In the sprawling, block-based universe of Minecraft, the competitive community has long gravitated toward specific versions of the game for their mechanical precision. Among these, version 1.8.9 remains the gold standard for Player vs. Player (PvP) combat. Within this ecosystem, a perpetual arms race exists between server administrators seeking fair play and players seeking an advantage. One of the most contentious additions to a player’s arsenal in this version is the "Anti-Knockback" mod, commonly referred to as "Anti-KB." While often dismissed as a simple cheat, the Anti-KB mod represents a significant subversion of Minecraft’s physics engine, fundamentally altering the risk-reward calculus of combat and serving as a primary catalyst for the modern anti-cheat industry.