A Network Traffic Analyser

Wireshark is a free network protocol analyzer for Unix and Windows. It
allows you to examine data from a live network or from a capture file
on disk. You can interactively browse the capture data, viewing summary
and detail information for each packet. Wireshark has several powerful
features, including a rich display filter language and the ability to
view the reconstructed stream of a TCP session.

WITHOUT-QT, WITHOUT GNUTLS