Thanks for your answer, just to let you know that I was playing in the server (interlude) and now that server is closed, because someone messed up server database and server settings through the NPC.
Admin told me that one guy injected something through the NPC and even server chat colors were blinking and different colour. All NPC showing errors, ALT+B not working, server is offline and they trying to rollback everything
So just wanted to ask if this is very hard to do it, or you just need special software and skills
He was using fake IP , so he got a ban, but server is messed up
Admin using l2jorion server packs