This was an excellent protocol analyzer. Now this is changed to Wireshark. The developers are still working in a very aggressive manner to improve more.
Supports most of the leading Operating systems.
EtherealR is used by network professionals around the world for troubleshooting, analysis, software and protocol development, and education. It has all of the standard features you would expect in a protocol analyzer, and several features not seen in any other product. Its open source license allows talented experts in the networking community to add enhancements. It runs on all popular computing platforms, including Unix, Linux, and Windows.