(PHP 4 >= 4.0.0)
ip2long -- Converts a string containing an (IPv4) Internet Protocol dotted address into a proper address.The function ip2long() generates an IPv4 Internet network address from its Internet standard format (dotted string) representation.
Note: Because PHP's integer type is signed, and many IP addresses will result in negative integers, you need to use the "%u" formatter of sprintf() or printf() to get the string representation of the unsigned IP address.
See also: long2ip()