using System;

using System.Net;

public class Program

{

    public static void Main() {

        String strHostName = string.Empty;

​

        // get the host name of local machine

        strHostName = Dns.GetHostName();

        Console.WriteLine("Local Machine's Host Name: " + strHostName);

        // using host name, get the IP address list

        IPHostEntry ipEntry = Dns.GetHostEntry(strHostName);

        IPAddress[] addr = ipEntry.AddressList;

        for (int i = 0; i < addr.Length; i++) {

            Console.WriteLine("IP Address {0}: {1} ", i, addr[i].ToString());

        }

​

        Console.WriteLine("\nChecking IP addresses...");

        IsLocalIpAddress("localhost");

        IsLocalIpAddress("127.0.0.1"); 

        IsLocalIpAddress("MyNotebook");

        IsLocalIpAddress("192.168.0.1");

        IsLocalIpAddress("99.0.0.1"); 

        Console.ReadLine();

    }

    public static bool IsLocalIpAddress(string host) {

        try {

            // get host IP addresses

            IPAddress[] hostIPs = Dns.GetHostAddresses(host);

            // get local IP addresses

            IPAddress[] localIPs = Dns.GetHostAddresses(Dns.GetHostName());

            // test if any host IP equals to any local IP or to localhost

            foreach (IPAddress hostIP in hostIPs) {

                // is localhost

                if (IPAddress.IsLoopback(hostIP)) {

                    return true;

                }

                // is local address

                foreach (IPAddress localIP in localIPs) {

                    if (hostIP.Equals(localIP)) {

                        return true;

                    }

                }

            }

        }

        catch(Exception ex) {

            Console.WriteLine("Error: " + ex.Message);

        }

        return false;

    }

}