Wireshark is a GTK+-based network protocol analyzer that lets you capture and interactively browse the contents of network frames. The goal of the project is to create a commercial-quality analyzer for Unix and Win32 and to give Wireshark features that are missing from closed-source sniffers. Screenshot available here.
You can download it from the following link: https://packetstormsecurity.com/files/download/54130/wireshark-0.99.5.tar.gz
Source: https://packetstormsecurity.com/files/54130/wireshark-0.99.5.tar.gz.html