The function ip2long generates a long integer representation of IPv4 Internet network address from its Internet standard format (dotted string) representation.
ip2long will also work with non-complete IP addresses. Read http://publibn.boulder.ibm.com/doc_link/en_US/a_doc_lib/libs/commtrf2/inet_addr.htm for more info.
A standard format address.
Returns the long integer or false if ip is invalid.
Because PHP's int type is signed, and many IP addresses will result in negative integers on 32-bit architectures, you need to use the "%u" formatter of sprintf or printf to get the string representation of the unsigned IP address.
ip2long will return -1 for the IP 255.255.255.255 on 32-bit systems due to the integer value overflowing.