There are many helpfull software utilities to help with HSMM. I have found a good network "sniffer" in Wireshark. Wireshark is free and will run on Windows or Linux. When you run this software, you choose which network interface on your computer to use and then it will display and log every packet that is transmitted or recieved on your network interface. This is a great program to learn about what happens on a network. It will also help to debug problems on your network. This software is a good thing to have in your HSMM toolbox. Try it out.