Okay, I'll explain it to you.
You should've heared about lag shoot.
If lagcomp mode is turned on, the players in your server have to shoot the target exactly at their skin.(NO LAGSHOOT)
If lagcomp mode is turned off, the player has to shoot infront of their target. (LAG SHOOTING)
So, lagcomp mode ON - No LAG SHOOT
lagcomp mode OFF - LAG SHOOT.
How to turn it off or on?
Open your server.cfg and make a new line.
If it should be on, then use
If it should be off, then use
Hope I helped you.