I have already sniffed the packets using Win2K's built in network monitor. I have text files that contain the byte information of each packet sent between the boxes. The application that I am testing claims to insert a special value into each packet so that the receiving application knows it came from the correct source. So, basically what I have is a lot of hex data that I'm trying to compare to see if I can determine what the "magic number" is, if it changes between runs, etc. Basically the problem is - given several sets of hex data, how do I find the patterns that show up in the largets number of sets?