Wireshark is the world’s foremost network protocol analyzer. It lets you see what’s happening on your network at a microscopic level. It is used for network troubleshooting, analyzing software and communication protocol development and education. Originally it was named Ethereal. In May 2006, the project was renamed Wireshark due to trademark issue.
One of the really good things of wireshark is that it does act of sniffing. Sniffing is the act of capturing data passing by a computer’s network interface. In simple terms, sniffing is eavesdropping or spying.
Administrators use sniffers to capture a typical data packet to help troubleshooting a network issue. Hackers use sniffers to capture sensitive data that may be useful to the hacker; such as passwords, emails, cookies or even files.