using System; using System.Text.RegularExpressions; public class EntryPoint { static void Main( string[] args ) { // Create regex to search for IP address pattern. string pattern = @" # First part match ([01]?dd? # OR |2[0-4]d # OR |25[0-5]) . # REPEAT ([01]?dd?|2[0-4]d|25[0-5]). # REPEAT ([01]?dd?|2[0-4]d|25[0-5]). # REPEAT ([01]?dd?|2[0-4]d|25[0-5]) "; Regex regex = new Regex( pattern, RegexOptions.IgnorePatternWhitespace ); Match match = regex.Match( "192.168.169.1" ); while( match.Success ) { Console.WriteLine( "IP Address found at {0} with " + "value of {1}", match.Index, match.Value ); match = match.NextMatch(); } } }