The Old New Thing

How do I write a regular expression that matches an IPv4 dotted address?

May 22, 2006 May 22, 2006 05/22/06

Raymond Chen

Writing a regular expression that matches an IPv4 dotted address is either easy or hard, depending on how good a job you want to do. In fact, to make things easier, let's match only the decimal dotted notation, leaving out the hexadecimal variant, as well as the non-dotted variants. For the purpose of this discussion, I'll restrict myself ...