any one know how to disable server eac

with another way not that :
server.eac 0

server.eac was deprecated years ago, it's no longer valid. What you need is:

server.secure 0
server.encryption 0​

Bear in mind that you will no longer appear on the in-game server list.

Sadly this will not enable you to run a client/server pair locally without internet connectivity. Whats that good for then?

Linux players can join for one thing.