I saw some guys giving themselves OP on servers.. They even hacked my server. How they do it? I don't want to hack servers, just interested in programming&hacking, and I was wondering what they exploit. Is it makes the job easier for them that my server is offline mode? Is it with the server version (like there is a vulnerability in a version)? Or they made a client that can give the player OP? (I don't really think that's possible, didn't personally test but.. big servers would be hacked.) And what can I do against hacking? I used OpGuard and it worked very well, but am I 100% safe with that?