During the process of analyzing a network problem with a network analyzer tool or a protocol sniffer, especially when we find a suspicious worm or backdoor activity, we get only useful information like MAC addresses, IP addresses and also the port number in transport layer. The analyzer may not even know which application layer protocol is used, even it tells, we still need to figure out which application or process is using this application layer protocol. We just complete a article named using Capsa to find out how to find out which process is using what port. Hopefully, it can bring values to someone intereted in this. You can download the enclosed PDF version or just read it on Colasoft blog.