Question

I was looking at the System.Net Namespace and it has an IPAddress instance you can use. This has a Parse method which you can use to parse a string into an IPInstance then use the Address property to give you the long value.

However…

The number returned is NOT the true conversion.

e.g. For IP 58.0.0.0 , the System.Net namespace gives me a value of 58… When in fact, the integer value should be 973078528

Can someone please show me the correct code do convert this?

The formula should be.. (for ip 192.1.20.10).

192 * (256*256*256) + 1 * (256*256) + 20 * (256) + 10

The reason this formula is correct is that the number it returns you can use in a >= and <= query to determine an IP address that falls within a range.

The Address Property (of the IPAddress instance) does not calculate/return this. A bonus point for anyone that knows why the address property does not return what I think is the correct answer…

Other examples from other links did not work either.

Answer 1

This might work, will try it and see.

public double IPAddressToNumber(string IPaddress)     {         int i;         string [] arrDec;         double num = 0;         if (IPaddress == '')         {             return 0;         }         else         {             arrDec = IPaddress.Split('.');             for(i = arrDec.Length - 1; i >= 0 ; i = i -1)                 {                     num += ((int.Parse(arrDec[i])%256) * Math.Pow(256 ,(3 - i )));                 }             return num;         }     }