This is the improved Minecraft Ban Command.
This bans the Player AND there IP so if they try to join on an alt account on the same internet connection then it wont work. You can just ban there IP on the ban-IP list BUT that sends a message to the entire server saying that it has been banned with the full IP in it. That brings them at risk of DDoS Attacks and there location being visible to total strangers and you could be held accountable for this since you made it visible. This plugin doesn't make this visible Since it only sends a Message saying they banned the Player.
How to Use
Just do the same command to ban someone like always (which is /ban <player>)