Packet Sniffers (10)
A packet analyzer (network analyzer, protocol analyzer, Ethernet sniffer or wireless sniffer) is a computer program or a piece of computer hardware that can intercept and log traffic passing over a digital network or part of a network. As data streams flow across the network, the sniffer captures each packet and, if needed, decodes the packet's raw data, showing the values of various fields in the packet, and analyzes its content.
Packet Filter (from here on referred to as PF) is OpenBSD's system for filtering TCP/IP traffic and doing Network Address Translation. PF is also capable of normalizing and conditioning TCP/IP traffic and providing bandwidth control and packet prioritization. PF has been a part of the GENERIC OpenBSD kernel since OpenBSD 3.0. Previous OpenBSD releases used a different firewall/NAT package which is no longer supported.
Ettercap is a comprehensive suite for man in the middle attacks. It features sniffing of live connections, content filtering on the fly and many other interesting tricks. It supports active and passive dissection of many protocols and includes many features for network and host analysis.
Driftnet watches network traffic, and picks out and displays JPEG and GIF images for display. It is an horrific invasion of privacy and shouldn't be used by anyone anywhere. It has been described as 'a graphical tcpdump', 'EtherPeg for Unix'. It is also possible to use driftnet to capture MPEG audio data from the network and play it through a player such as mpg123.