Wireshark is a free tool that can be used for network protocol analysis and testing. This is being widely used standard for analysing network protocols. The key features includes
- Supports analysing of hundreds of protocols.
- Provides live capture and offline analysis
- Supports Windows, Solaris, Linux and other operating system.
- Provides displays filters and VOIP analysis.
- It read and write different capture file formats such as Microsoft Network Monitor, tcpdump, Cisco Secure IDS iplog and many others
- Live data can be read from Ethernet, IEEE 802.11, PPP/HDLC, ATM, Bluetooth, USB, Token Ring, Frame Relay, FDDI, and others
For a detailed information check the below this link.