Validating IPAddress using Regular Expression in C#.

public bool IsValidIPAddress(string ipAddr)
{
string pattern = @"^([1-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(\.([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3}$";
Regex reg = new Regex(pattern, RegexOptions.Singleline | RegexOptions.ExplicitCapture);
return reg.IsMatch(ipAddr);
}