Dns Class

Provides domain name resolution.

For a list of all members of this type, see Dns members.

Inheritance Hierarchy

System.Object
   System.MarshalByRefObject
      System.ComponentModel.Component
         Dart.PowerTCP.SslSockets.Dns

Syntax

[Visual Basic]
<DescriptionAttribute("The Dns Component resolves names, addresses, and mail servers.")>
<LicenseProviderAttribute(DnsLicenseProvider)>
Public Class Dns 
   Inherits Component

[C#]
[DescriptionAttribute("The Dns Component resolves names, addresses, and mail servers.")]
[LicenseProviderAttribute(DnsLicenseProvider)]
public class Dns : Component

[C++]
[DescriptionAttribute("The Dns Component resolves names, addresses, and mail servers.")]
[LicenseProviderAttribute(DnsLicenseProvider)]
public __gc class Dns : public Component

[C++/CLI]
[DescriptionAttribute("The Dns Component resolves names, addresses, and mail servers.")]
[LicenseProviderAttribute(DnsLicenseProvider)]
public ref class Dns : public Component

Remarks

The Domain Name System (DNS) uses servers distributed across the Internet to provide domain name/IP address translation and electronic mail routing information.

The Dns class provides forward lookup (resolve a name to an address), reverse lookup (resolve an address to a name), and MX lookup (resolve an email address to the mail server address responsible for that mail domain). Synchronous and asynchronous use is fully supported.

Example

The following example demonstrates using the Dns control to resolve a domain name.

[Visual Basic]

Private Sub ResolveTest()

   Dns1.Servers.Add("206.64.128.5") 'Adds this server to list of DNS servers

   Dns1.RotateServers = True 'Will always try next server in Dns1.Servers

   Dns1.Retries = 2 'On failures, try an additional two times

   Dns1.RetryInterval = 0 'Do not wait between retries

   Dim result As System.Net.IPHostEntry = Dns1.GetHost("www.dart.com")

   DisplayResult(result)

End Sub



Private Sub DisplayResult(ByVal result As System.Net.IPHostEntry)

   ' Display host name

   Debug.WriteLine("Host name: " + result.HostName)



   ' Display addresses, if any

   Dim add As System.Net.IPAddress

   For Each add In result.AddressList

      Debug.WriteLine("Address: " + add.ToString())

   Next



   ' Display aliases, if any

   Dim s As String

   For Each s In result.Aliases

      Debug.WriteLine("Aliases: " + s)

   Next

End Sub

[C#]



private void ResolveTest()

{

  dns1.Servers.Add("206.64.128.5"); 'Adds this server to list of
DNS servers

  dns1.RotateServers = true; 'Will always try next server in Dns1.Servers

  dns1.Retries = 2; 'On failures, try an additional two times

  dns1.RetryInterval = 0; 'Do not wait between retries

  System.Net.IPHostEntry result = dns1.GetHost("www.dart.com");

  DisplayResult(result);

}


private void DisplayResult(System.Net.IPHostEntry result)

{

  // Display host name

  Debug.WriteLine("Host name: " + result.HostName);



  // Display addresses, if any

  foreach(System.Net.IPAddress add in result.AddressList)

     Debug.WriteLine("Address: " + add.ToString());



  // Display aliases, if any

  foreach(string s in result.Aliases)

     Debug.WriteLine("Aliases: " + s);

}

Requirements

Namespace: Dart.PowerTCP.SslSockets

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

Assembly: Dart.PowerTCP.SslSockets (in Dart.PowerTCP.SslSockets.dll)

See Also

Requirements

Language

Dns Class

Inheritance Hierarchy

Syntax

Remarks

Example

Requirements

See Also