A free ethernet protocol analyzer / sniffer K.ARP.SKI (karpski) is an ethernet protocol analyzer / sniffer. Its abilities as a sniffer or scanner are limited, but this sniffer is much easier to use than other popular sniffers such as tcpdump. In addition, there is a protocol definition file in which other protocols can be added. Karpski may also be used to launch programs against addresses on your local network and as a local network intrusion tool. Plus, it's free with source. Its display is an Xwindows display. This was a design decision based on my need to display many windows simultaneously. Console mode would just not cut it. I chose the Gtk display library because it's proven, portable and free. You may not like my choice\; the source is included. This program was originally based on my desire to detect someone plugging an unauthorized computer into a LAN. It did this originally by looking at ARP packets. This is where the arp in karpski comes from.