I've used them extensively in the past - I ran the technology end of a .com a few years ago - for a number of years.
I always like to jump right into the network stream as you'll find a lot of problems can be solved faster by looking at the data being pushed back and forth - where it is going - what types etc. vs. clicking buttons and changing code.
If you change something and can't really see what it is doing, what is being accomplished?
You don't really need a filter until you figure out what is actually going wrong - so I'd say the first step is to actually look at the raw data and go from there.
Maybe I'll have to figure out how the darned multiplayer portion of this sim works so I can poke around and see if I see anything funny - but I wouldn't know where to start vs. you multiplayer vets.