Regular Expressions IP Address Validation with .net

This regular expression will check for valid Internet Protocol (IP) address. Here we are going to search four decimal numbers groups, each separated by a dot. each set contains zero to three digits. Here regular expression check for two group which on concatenation generate a valid IP address. First group select from 3 alternatives which will find decimal number range from 0 to 255 ending with .(dot or period), exactly 3 repetitions and Second group select from 3 alternatives which will find decimal number range from 0 to 255.