I use Wireshark quite all the time. I was lucky to get a copy
of Hacking: The Art of Exploitation when I was a teenager, the book gave
me an excellent introduction to using
tcpdump to perform network analysis.
tcpdump is the first tool I reach for when I wonder where the packets are
going, but for anything higher level (breaking down http, checking wlan flags)
wireshark, I am always impressed.
At 33c3 there was a
wireshark introductory self organised session run by
kirils. I did not go to this session, but the slides I found look to
be an excellent introduction to using
Reading: Babylon's Ashes
Aberdeen, Scotland: -3°C, Light rain overnight.