Reputation: 4538
I tried this code for validating IP address, but it doesn't work...
public static bool IP(string ipStr)
{
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}$";
Regex check = new Regex (pattern);
bool valid = false;
if (ipStr == "") {
valid = false;
} else {
valid = check.IsMatch (ipStr, 0);
}
return valid;
}
Any idea what's wrong?
Upvotes: 10
Views: 30666
Reputation: 201
Here is the complete regex for checking all possible IPv4 addresses (dotted decimal, dotted hexadecimal, dotted octal, decimal, hexadecimal, octal and mixed mode)
^(0[0-7]{10,11}|0(x|X)[0-9a-fA-F]{8}|(\b4\d{8}[0-5]\b|\b[1-3]?\d{8}\d?\b)|((2[0-5][0-5]|1\d{2}|[1-9]\d?)|(0(x|X)[0-9a-fA-F]{2})|(0[0-7]{3}))(\.((2[0-5][0-5]|1\d{2}|\d\d?)|(0(x|X)[0-9a-fA-F]{2})|(0[0-7]{3}))){3})$
I have tested it with all possible addresses.
Upvotes: 1
Reputation: 3215
for match a valid IP adress use
^(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)(\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$
instead of
^([01]?[0-9][0-9]?|2[0-4][0-9]|25[0-5])(\.([01]?[0-9][0-9]?|2[0-4][0-9]|25[0-5])){3}$
because many regex engine match the first possibility in the OR sequence
you can try your regex engine : 10.48.0.200
test the difference here
Upvotes: 7
Reputation: 1512
There is a previously answered question available for a valid IP address.
As for debugging regular expressions, on Windows I heartily recommend Expresso. On the web, there is a free Flash-based tester available.
Upvotes: 2
Reputation: 116178
I would use IPAddress.TryParse
static method instead.
IPAddress ip;
bool b = IPAddress.TryParse("1234.12.12.12",out ip);
Upvotes: 63
Reputation: 17680
I'm not really a regex expert per se but i use Expresso (a regex tool) and it has it's own regex library for pre-set scenarios like this. Try this below.
string pattern = @"(?<First>2[0-4]\d|25[0-5]|[01]?\d\d?)\.(?<Second>2[0-4]\d|25[0-5]|[01]?\d\d?)\.(?<Third>2[0-4]\d|25[0-5]|[01]?\d\d?)\.(?<Fourth>2[0-4]\d|25[0-5]|[01]?\d\d?)";
Upvotes: 1