Here is where a network analyser comes in handy. It will sniff the raw packets of data flying about as they happen and give you meaningful information to make intelligent determinations.
Previously I have talked about the tremendous open source product WireShark but WireShark isn't for everyone. For one, the Windows port requires GTK+ and Glib to be installed which some Windows administrators aren't keen to do. For another, although it is less arcane and cryptic than a command-line tool like tcpdump it's still not user-friendly enough for many.
Here is where Colasoft's Capsa product comes in. As you might guess, it is a deep low-level network protocol analyser and its purpose is to give you the low-down on just what is happening on your network.
Where it stands out from the competition is its brilliant ease of use. Capsa adopts the same ribbon style interface as seen in Microsoft Office 2007 and it is a snap to navigate between tabs and check out the options and power available.
When it comes to network analysis so much is going on that it's a must to separate out the chatter from the data that matters. Capsa makes it a cinch to hone in on what you want with easy to use filters and rules.