netsniff-ng is is a free, performant Linux network sniffer for packet inspection.
The gain of performance is reached by 'zero-copy' mechanisms, so that the kernel does not need to copy packets from kernelspace to userspace.
For this purpose netsniff-ng is libpcap independent, but nevertheless supports the pcap file format for capturing, replaying and performing offline-analysis of pcap dumps. Furthermore we are focussing on building a robust, clean and secure analyzer and utilities that complete netsniff-ng as a support for penetration testing.
netsniff-ng can be used for protocol analysis, reverse engineering and network debugging.