\b Match a word boundary
If you are trying to match an IP address in a paragraph of text you would need to use the "\b". In my example I would assume that the input would onl;y be the IP address text. In this case as Glenn points out, I expect only the IP address. Without the ^ and $ to signify the beginning and end of the string, the user could entery "asc@#$100.200.103.45something else" and the RegEx would match.
