♦ Get a remote IP Addeess

Figure 1: Output Screen show find "youtube.com" ip address.


Figure 2: Output Screen find "Lan" ip address.



Figure 3: Output screen with invalid input.


This is example the way we can find Remote ip address.

Class Definition:
                  System.Net
                 - Dns class
                         - GetHostAddresses method

Syntax:
                    public static IPAddress[] GetHostAddresses (
                                        string hostNameOrAddress
                     )

Parameters : hostNameOrAddress
                      Type: System.String
                      The host name or IP address to resolve.

Return Value:
                    Type: System.Net.IPAddress[]
                    An array of type IPAddress that holds the IP addresses for the host that is specified by the
                    hostNameOrAddress parameter.
                   
                    The IPAddress class contains the address of a computer on an IP network.

//Form1.cs
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Net;

namespace gethostip
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1FindClick(object sender, EventArgs e)
        {
            string hostname = "";
            hostname = textBoxInput.Text;

                try
                {
                    IPAddress[] ipaddr = System.Net.Dns.GetHostAddresses(hostname);
                    for (int i = 0; i < ipaddr.Length; i++)
                    {
                        textBoxOutput.Text += "" + ipaddr[i].ToString() + Environment.NewLine;
                    }
                }
                catch (System.Net.Sockets.SocketException )
                {
                    textBoxOutput.Text = "No such host is known";
                }
          }

        private void button2ClearClick(object sender, EventArgs e)
        {
            textBoxOutput.Text = "";
        }
           
     }
    
 }

 

Remark : To protect some Error when you run this program in case you enter invalid format of hostname and/or IP Address format. so you should have ...
      try {
             ...
      }
      catch (System.Net.Sockets.SocketException) {
             ... your error message here ... 
      }

    If you have "run" this program without ...try exception... and input invalid hostname such as " 5a.5a 999" the debuger will report you with error message..."System.Net.Sockets.SocketException : no such host known". where become to me known what we do catch for...?    System.Net.Sockets.SocketException