ZLINE

Usage: ZLINE <ip range>
This command is a form of firewall for your server. This will prevent problem users from a specified host address from accessing the server.
Examples:
/zline 10.127.0.1-10.127.1.255
This is the strongest ban you can place against an address. The person will not even see a reason why they are banned; they will just be unable to connect. The ban must be set on the numeric version of the address.