I'm currently converting a whole lot of IP address data from some quite ghastly flat files.Ghastliness aside, I'm trying to sort out a way to check each IP listed to check if it's a subnet address ...

In this article I'll show you how to make a simple IP address notifier. ... To use the program, you'll need Python 2.7 or later, urllib2, and a program called "text" (see this article here to get it).