NAT
Last updated: 2/28/03

Q.  What is a NAT?

A.  NAT is an abbreviation for Network Address Translation.  A NAT, as the term is commonly used, is a software/hardware device that performs the function.  Basically, as frequently used on this web site, a NAT translates packets from local network Private Internet Protocol (IP) addresses into an Internet IP address and vice versa.  For example, if one uses a combination broadband router/Ethernet switch to share an Internet connection provided by a cable MODEM, the service provider's system assigns and Internet IP address to the router via the cable MODEM.  A NAT inside the router translates that IP address information in the packets of data from the Internet to local IP addresses assigned to the PCs connected to the router.  Local address info in packets sent to the Internet from the PCs  is translated to the router's Internet IP.

More information than you will probably want to know on the subject is available at http://www.suse.de/~mha/linux-ip-nat/diplom/nat.html.