Im Requesting This Plugin Because Im Making A Custom Client And I Want All My Users To Use It Maybe If It Detects A Certain File It Will Let Them Join And When There Kicked Maybe A Custom Message???
Why Do You Capitalize Every Word In Your Sentences? (I can't keep doing that, its just too annoying). Why you want to do is illegal first and foremost seeing as it is illegal to distribute "hacked" (code for changed) minecraft clients without Notch's explicit approval. Regardless, I don't believe that it can be done because you would have to add your own code TO THE CLIENT that tells the server when Zombe's mod is installed. I know that Spout can do this automatically. Long story short, you aren't going to find a plugin dev that will do something illegal for you.
I have made a plugin at least similar to what you want. Here it is: http://forums.bukkit.org/threads/admn-sec-spoutdemand-1-2-allow-only-spout-clients-1000.31018/
I think he is making a client MOD. Just a few obfuscated class files that get put into minecraft.jar, just like any other client mod. Not illegal. Well done! EDIT by Moderator: merged posts, please use the edit button instead of double posting.
I didn't say client mods are illegal, I said that distributing hacked (read: altered) game clients is illegal.
Yes. All of Notch's code is copyrighted. But, once the sales die down, he plans to release the code under Creative Commons!
I don't see sales dying down anytime soon and I thought he said that he didn't like CC because it gave the original developer too much power so he will be releasing it into the public domain.