Free Programming Tutorials & Source Code

The following sample will show you how to get DNS Reverse Lookup for a particular IP. It uses the System.Net namespace.

First, add the following controls to your form:
TextBox. Name it as txtHostName
Button. Name it as btnDNSReverseLookup



Add the following Namespace:

using System.Net;
 

And the function:

 string DNSLookup(IPHostEntry iphe)
           { 
              String str;
               str = "";

               str += "Host Name:\n" + iphe.HostName;
               str += "\n\nAliases:\n";
               foreach (string alias in iphe.Aliases)
            {
                str += alias + "\n";
            }

            str +="\nAddresses:" ; 
            foreach (IPAddress address in iphe.AddressList) 
            { 
                str += "\n"+ address.ToString();
            }
           
            return str; 
        } 

And the btnDNSReverseLookup Click Event:

 private void btnDNSReverseLookup_Click(object sender, EventArgs e)
        { 
            try
            {
                IPHostEntry ipHostEntry = Dns.GetHostByAddress(this.txtHostName.Text);
             MessageBox.Show(   DNSLookup(ipHostEntry)); 
            }
            catch (Exception ex) 
            { 
                MessageBox.Show(ex.Message);
            }
        }

You may also see DNS Lookup in C#

Happy Coding!