http://tcllib.sourceforge.net/doc/tcllib_ip.html The '''Internet Protocol''' (described in RFC 791 [http://www.ietf.org/rfc/rfc0791.txt]), which controls how machines talk to and address each other. Usually you have [TCP] or [UDP] layered over the top to provide port-based addressing and checksums... The most common version of IP at the moment is version 4, though you may well also see version 6 about from time to time (mostly at very large ISPs though.) The currently used checksum in IPV4 as described in RFC 791 [http://www.ietf.org/rfc/rfc0791.txt] is known as the [Internet Checksum]. [[Need more info on the difference between IPv4 and IPv6...]] If you need to manipulate internet addresses, read [Handling internet addresses]. You may also be interested in the [DNS] page for turning hostnames into addresses. See also [A Little CIDR Calculator] ---- [[ [Category Acronym] | [Category Internet] | [Category Networking] ]]