Sniffer

Sniffers were originally used exclusively by network engineers, however they have become popular on the internet with hackers, and the U.S federal Bureau of investigation (FBI) had utilized a famous sniffer system called “Carnivore” to help detect illegal internet communication over email.
 * Sniffers**, also known as network monitors or packet sniffers, are self-contained software programs or hardware devices. They act as network searching or “snooping” tools, allowing precisely filtered viewing of web traffic. As the data flow thought the network, the sniffer captures the packets and decodes and analyzes them by content. They examine transparently, copying the data without redirecting or altering it. Some sniffers work only with TCP and UDP based packets, but the more complicated tools can work with many other protocols and even at lower levels including to Ethernet frames.



Packet data of DNS (Domain Name System) reply to Aureate software's request for the IP address of its default server 'aim1.adsoftware.com'

Work Cited
Sniffer. Webopedia Computer Dictionary. 2005 http://www.webopedia.com/TERM/S/sniffer.html