Introducing Radical.sh

Forget Code launches a powerful code generator for building API's

Checking for Local IP Address in C#

  1. Forget Code
  2. C#
  3. Checking for Local IP Address
How the things will be?
1.Get the host name first by Dns.GetHostName();
2. Save the IP address in IPHostEntry by Dns.GetHostByName(hostName);
3. Using IPAddress array, get the actual host address.
4. Using IPAddress array, get the host address of local.
5. Compare the results of step 3 and 4.

For example, we are getting our local host and sending for the check.
You can check with the other remote IPs also by passing remote host while calling the bool method.
  1. using System;
  2. using System.Net;
  3.  
  4. public class ForgetCode
  5. {
  6.     static string IPHost;
  7.     public static void Main()
  8.     {
  9.         UseDNS();
  10.     }
  11.  
  12.     public static void UseDNS()
  13.     {
  14.         string hostName = Dns.GetHostName();
  15.         IPHostEntry local = Dns.GetHostByName(hostName);
  16.         
  17.         foreach (IPAddress ipaddress in local.AddressList)
  18.         {
  19.             IPHost = ipaddress.ToString();
  20.         }
  21.  
  22.         if (isLocal(IPHost))
  23.         {
  24.             Console.WriteLine("Yes, it is a local system");
  25.         }
  26.         else
  27.         {
  28.             Console.WriteLine("No, it is not a local system"); 
  29.         }
  30.  
  31.     }
  32.  
  33.     public static bool isLocal(string host)
  34.     {
  35.         try
  36.         {
  37.             IPAddress[] hostIPs = Dns.GetHostAddresses(host);
  38.             // get local IP addresses
  39.             IPAddress[] localIPs = Dns.GetHostAddresses(Dns.GetHostName());
  40.  
  41.             // test if any host IP equals to any local IP or to localhost
  42.             foreach (IPAddress hostIP in hostIPs)
  43.             {
  44.                 // is localhost
  45.                 if (IPAddress.IsLoopback(hostIP)) return true;
  46.                 // is local address
  47.                 foreach (IPAddress localIP in localIPs)
  48.                 {
  49.                     if (hostIP.Equals(localIP)) return true;
  50.                 }
  51.             }
  52.         }
  53.         catch { }
  54.         return false;
  55.     }
  56. }


If it is a local IP address then the output will be
Yes, it is a local system