In 2010 Riverbed Technology purchased CACE and took over as the primary sponsor of Wireshark. However, he did not own the Ethereal trademark, so he changed the name to Wireshark. Combs still held copyright on most of Ethereal's source code (and the rest was re-distributable under the GNU GPL), so he used the contents of the Ethereal Subversion repository as the basis for the Wireshark repository. In May 2006, Combs accepted a job with CACE Technologies. The Ethereal trademark is owned by Network Integration Services. The commercial protocol analysis products at the time were priced around $1500 and did not run on the company's primary platforms (Solaris and Linux), so Gerald began writing Ethereal and released the first version around 1998. In the late 1990s, Gerald Combs, a computer science graduate of the University of Missouri–Kansas City, was working for a small Internet service provider. If a remote machine captures packets and sends the captured packets to a machine running Wireshark using the TZSP protocol or the protocol used by OmniPeek, Wireshark dissects those packets, so it can analyze packets captured on a remote machine at the time that they are captured. On Linux, BSD, and macOS, with libpcap 1.0.0 or later, Wireshark 1.4 and later can also put wireless network interface controllers into monitor mode. Simple passive taps are extremely resistant to tampering. Port mirroring or various network taps extend capture to any point on the network. However, when capturing with a packet analyzer in promiscuous mode on a port on a network switch, not all traffic through the switch is necessarily sent to the port where the capture is done, so capturing in promiscuous mode is not necessarily sufficient to see all network traffic. Wireshark lets the user put network interface controllers into promiscuous mode (if supported by the network interface controller), so they can see all the traffic visible on that interface including unicast traffic not sent to that network interface controller's MAC address.

Wireshark is very similar to tcpdump, but has a graphical front-end and integrated sorting and filtering options.

Wireshark captures what kind of traffic