Match IPv4 address given IP range/mask?

Question

Either with PHP or a RegExp (or both), how do I match a range of IP addresses?

Sample Incoming IPs

10.210.12.12
10.253.12.12
10.210.12.254
10.210.1         


        

Answer 1

Regex really doesn't sound like the right tool to deal with subnet masks (at least not in decimal). It can be done, but it will be ugly.

I strongly suggest parsing the string into 4 integers, combining to a 32-bit int, and then using standard bitwise operations (basically a bitwise-AND, and then a comparison).