get client action from bytes

Hi.

I have a "minecraft" server in my pc. and i am writing a tunnel to block some actions from the players.

so, the client's connect to my program, and i foward all bytes received, to the server, and the same when the server send something to the client.

Code:

---

while ((bytesRead = In.read(byteBuffer)) != -1) {
                if (Debug.dmode && isClient ) {
                    //System.out.println("byte %d" + totalBytesMoved);
                    //System.out.println(stringToHex(new String(byteBuffer)));
                    //System.out.println(byteBuffer[0]);
                }

                Out.write(byteBuffer, 0, bytesRead);
                Out.flush();
 }

---

It works, i can play the game with the tunnel working, and print only the bytes that the client send to the server.

The problem is, i want to block an specific action, (destroying block from a certain area - if you know the game), and i cant understand the actions from the bytes.. i tried so many times to see the bytes, but look like its not the same to same action, because maybe the content, like position of the player, are in 2 or more bytes.

anybody have any idea of how to do it?

Thx for all.
sorry for the english