Net::IPAddr is a collection of helpful functions used to convert IP addresses to/from 32-bit integers, applying subnet masks to IP addresses, validating IP address strings, and splitting a FQDN into its host and domain parts. No rocket science here, but I have found these functions to very, very handy. For example, have you ever tried to sort a list of IP addresses only to find out that they don't sort the way you expected? Here is the solution! If you convert the IP addresses to 32-bit integer addresses, they will sort in correct order. WWW: http://search.cpan.org/dist/Net-IPAddress/