How to determine whether an IP address is private?

Question

So far I have this code:

NetworkInterface[] adapters = NetworkInterface.GetAllNetworkInterfaces();  foreach (NetworkInterface adapter in adapters) {   IPInterfaceProperties properties = adapter.GetIPProperties();    foreach (IPAddressInformation uniCast in properties.UnicastAddresses)   {      // Ignore loop-back addresses & IPv6     if (!IPAddress.IsLoopback(uniCast.Address) &&        uniCast.Address.AddressFamily!= AddressFamily.InterNetworkV6)         Addresses.Add(uniCast.Address);   } } 

How can I filter the private IP addresses as well? In the same way I am filtering the loopback IP addresses.

Answer 1

A more detailed response is here:

private bool _IsPrivate(string ipAddress) {     int[] ipParts = ipAddress.Split(new String[] { "." }, StringSplitOptions.RemoveEmptyEntries)                              .Select(s => int.Parse(s)).ToArray();     // in private ip range     if (ipParts[0] == 10 ||         (ipParts[0] == 192 && ipParts[1] == 168) ||         (ipParts[0] == 172 && (ipParts[1] >= 16 && ipParts[1] <= 31))) {         return true;     }      // IP Address is probably public.     // This doesn't catch some VPN ranges like OpenVPN and Hamachi.     return false; }