/// <summary>
/// method to validate an IP address
/// using regular expressions. The pattern
/// being used will validate an ip address
/// with the range of 1.0.0.0 to 255.255.255.255
/// </summary>
/// <param name="addr">address to validate</param>
/// <returns></returns>
public bool IsValidIP(string addr)
{
//create our match pattern
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}$";
//create our regular Expression object
Regex check = new Regex(pattern);
//boolean variable to hold the status
bool valid = false;
//check to make sure an ip address was provided
if (addr == "")
{
//no address provided so return false
valid = false;
}
else
{
//address provided so use the IsMatch Method
//of the regular Expression object
valid = check.IsMatch(addr, 0);
}
//return the results
return valid;
}