Question

Following is my code to get the default NIC in Windows XP, but the same code doesn’t work in Windows 7. It’s really confusing after reading MSDN. Any solution?

//----------------- Getting all the Nic's --------------------
foreach (NetworkInterface nic in NetworkInterface.GetAllNetworkInterfaces())
{
    //------------ Getting properties of IPV4 ----------------
    IPInterfaceProperties ipProps = nic.GetIPProperties();

    //------------ Getting the Ip Properties -----------------
    if (ipProps.GetIPv4Properties() != null)
    {
        dic.Add(ipProps.GetIPv4Properties().Index, nic.Name);
    }

Error: The request protocol is not configured, or has no implementation.

Answer 1

It means you are hitting interface without IPv4 support on it.
Check for it with:

if (nic.Supports(NetworkInterfaceComponent.IPv4)) // means IPv4 support is present

See here for more.