As I always say in my presentations, it doesnt take much to use a Protocol Analyzer and capture some packets. Usually you can quickly perform a high level analysis to better understand your applications.
Many people I speak to are always under the impression that basic protocol analysis is a long drawn out process and many times it is not.
In this video I use Wireshark to better understand how this discovery utility finds IP addresses and names.
I always remind people that in many professions, people are encouraged to try their tools before they need them in the field, like doctors, police and firemen. Why try to figure out protocols and packets in the middle of a crisis.