IP address parsing in .NET

Question

I'm using IPAddress.TryParse() to parse IP addresses. However, it's a little too permissive (parsing "1" returns 0.0.0.1). I'd like to limit the input to dotted octet notation. What's the best way to do this?

(Note: I'm using .NET 2.0)

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Edit

Let me clarify:

I'm writing an app that will scan a range of IPs looking for certain devices (basically a port scanner). When the user enters "192.168.0.1" for the starting address, I want to automatically fill in "192.168.0.255" as the ending address. The problem is that when they type "1", it parses as "0.0.0.1" and the ending address fills in as "0.0.0.255" - which looks goofy.

Answer 1

If you are interested in parsing the format, then I'd use a regular expression. Here's a good one (source):

bool IsDottedDecimalIP(string possibleIP)
{
    Regex R = New Regex(@"\b(?:\d{1,3}\.){3}\d{1,3}\b");
    return R.IsMatch(possibleIP) && Net.IPAddress.TryParse(possibleIP, null);
}

That regex doesn't catch invalid IPs but does enforce your pattern. The TryParse checks their validity.