With ckecksum no matter if they know your ip or serial, then they can not enter without the original main with antihack mu emu or whichever you add
Go to \DTData\Common
and change it
EnableCheckSum =
1 // 1 - Enable checksum, 0 - disable checksum
Make checksum to your main with this program
CheckSum Generator when you finish adding the anti cheat and paste it on \Data\lang\kor
And nobody can enter now without that main with checksum and antihack