Does somebody know about some software for network analysis?

try sam spade thats quite good at network analysis, also have a look for a thing called backtrack, its a linux security cd, which is live, there both free by the way

Check out SnapFiles.com (http://www.snapfiles.com/freeware/)
and look under the ‘Network’ section. They are all freeware and you can read about what each does, how users rate the programs, as well as ratings from the site’s creator(s).

Hobbit isn’t bad, depending on what you’re wanting to analyze. It’s very flexible and easy to monitor via the GUI.