A network protocol analyzer to capture packets and detect errors

Wireshark is an awesome, free (gpl) multiplatform software (also available for Mac), belonging to the category Networking software and has been published by Wireshark Foundation.

More about Wireshark

About the download, Wireshark is a program that will require less storage than the average program in the section Networking software. It’s a program mostly downloaded in Hungary, Latvia, and Thailand.Since we added this software to our catalog in 2011, it has managed to reach 51,284 downloads, and last week it achieved 5 downloads.Wireshark is available for users with the operating system Windows 2000 and previous versions, and you can download it in English. Its current version is 1.6.8 and was updated on 5/24/2012.