OK, Since I started blocking the hacker’s IP address ranges on the external router, I have not seen any further intrusion attempts. But it could just be a matter of time until they find an IP range I’m not blocking. But we’ve also added an anti-griefing server plugin to try to limit the damage if they do get in again. I’ll stay on top of it!
If you want to read up on how the GriefProtection system works, you can go here. Or, if you prefer videos, here ya go!
The #1 Anti-Grief Minecraft Server Plugin : Grief Prevention – YouTube