Wireshark (formerly Ethereal, renamed for copyright reasons) is a network traffic analyser created in 1998.
It is used by numerous administrators to diagnose complex network problems. Available in the form of a large graphics application as well as a text mode interface, it can decode a very large number of protocols, including encrypted ones.
It is available under the GPL.
Wireshark is multi-platform, running on Windows, Mac OS X, Linux, Solaris and FreeBSD. Wireshark recognises more than 700 network and application protocols.
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