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IPAddress Class

Provides an Internet Protocol (IP) address.

For a list of all members of this type, see IPAddress Members.

System.Object
   System.Net.IPAddress

[Visual Basic]
<Serializable>
Public Class IPAddress
[C#]
[Serializable]
public class IPAddress
[C++]
[Serializable]
public __gc class IPAddress
[JScript]
public
   Serializable
class IPAddress

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Remarks

The IPAddress class contains the address of a computer on an IP network.

Example

[Visual Basic, C#, C++] The following code example shows how to query a server to obtain the family addresses and the IP addresses it supports.

[Visual Basic] 
' This program shows how to use the IPAddress class to obtain a server 
' IP addressess and related information.
Imports System
Imports System.Net
Imports System.Net.Sockets
Imports System.Text.RegularExpressions
Imports Microsoft.VisualBasic


Namespace Mssc.Services.ConnectionManagement
  Module M_TestIPAddress

    Class TestIPAddress

      'The IPAddresses method obtains the selected server IP address information.
      'It then displays the type of address family supported by the server and 
      'its IP address in standard and byte format.
      Private Shared Sub IPAddresses(ByVal server As String)
        Try
          Dim ASCII As New System.Text.ASCIIEncoding()

          ' Get server related information.
          Dim heserver As IPHostEntry = Dns.Resolve(server)

          ' Loop on the AddressList
          Dim curAdd As IPAddress
          For Each curAdd In heserver.AddressList

            ' Display the type of address family supported by the server. If the
            ' server is IPv6-enabled this value is: InternNetworkV6. If the server
            ' is also IPv4-enabled there will be an additional value of InterNetwork.
            Console.WriteLine(("AddressFamily: " + curAdd.AddressFamily.ToString()))

            ' Display the ScopeId property in case of IPV6 addresses.
            If curAdd.AddressFamily.ToString() = ProtocolFamily.InterNetworkV6.ToString() Then
              Console.WriteLine(("Scope Id: " + curAdd.ScopeId.ToString()))
            End If

            ' Display the server IP address in the standard format. In 
            ' IPv4 the format will be dotted-quad notation, in IPv6 it will be
            ' in in colon-hexadecimal notation.
            Console.WriteLine(("Address: " + curAdd.ToString()))

            ' Display the server IP address in byte format.
            Console.Write("AddressBytes: ")



            Dim bytes As [Byte]() = curAdd.GetAddressBytes()
            Dim i As Integer
            For i = 0 To bytes.Length - 1
              Console.Write(bytes(i))
            Next i
            Console.WriteLine(ControlChars.Cr + ControlChars.Lf)
          Next curAdd 

        Catch e As Exception
          Console.WriteLine(("[DoResolve] Exception: " + e.ToString()))
        End Try
      End Sub 'IPAddresses


      ' This IPAddressAdditionalInfo displays additional server address information.
      Private Shared Sub IPAddressAdditionalInfo()
        Try
          ' Display the flags that show if the server supports IPv4 or IPv6
          ' address schemas.
          Console.WriteLine((ControlChars.Cr + ControlChars.Lf + "SupportsIPv4: " + Socket.SupportsIPv4.ToString()))
          Console.WriteLine(("SupportsIPv6: " + Socket.SupportsIPv6.ToString()))

          If Socket.SupportsIPv6 Then
            ' Display the server Any address. This IP address indicates that the server 
            ' should listen for client activity on all network interfaces. 
            Console.WriteLine((ControlChars.Cr + ControlChars.Lf + "IPv6Any: " + IPAddress.IPv6Any.ToString()))

            ' Display the server loopback address. 
            Console.WriteLine(("IPv6Loopback: " + IPAddress.IPv6Loopback.ToString()))

            ' Used during autoconfiguration first phase.
            Console.WriteLine(("IPv6None: " + IPAddress.IPv6None.ToString()))

            Console.WriteLine(("IsLoopback(IPv6Loopback): " + IPAddress.IsLoopback(IPAddress.IPv6Loopback).ToString()))
          End If
          Console.WriteLine(("IsLoopback(Loopback): " + IPAddress.IsLoopback(IPAddress.Loopback).ToString()))
        Catch e As Exception
          Console.WriteLine(("[IPAddresses] Exception: " + e.ToString()))
        End Try
      End Sub 'IPAddressAdditionalInfo

      Public Shared Sub Main(ByVal args() As String)
        Dim server As String = Nothing

        ' Define a regular expression to parse user's input.
        ' This is a security check. It allows only
        ' alphanumeric input string between 2 to 40 character long.
        'Define a regular expression to parse user's input.
        'This is a security check. It allows only
        'alphanumeric input string between 2 to 40 character long.
        Dim rex As New Regex("^[a-zA-Z]\w{1,39}$")

        If args.Length < 1 Then
          ' If no server name is passed as an argument to this program, use the current 
          ' server name as default.
          server = Dns.GetHostName()
          Console.WriteLine(("Using current host: " + server))
        Else
          server = args(0)
          If Not rex.Match(server).Success Then
            Console.WriteLine("Input string format not allowed.")
            Return
          End If
        End If

        ' Get the list of the addresses associated with the requested server.
        IPAddresses(server)

        ' Get additonal address information.
        IPAddressAdditionalInfo()
      End Sub 'Main
    End Class 'TestIPAddress
  End Module
End Namespace

[C#] 

// This program shows how to use the IPAddress class to obtain a server 
// IP addressess and related information.

using System;
using System.Net;
using System.Net.Sockets;
using System.Text.RegularExpressions;

namespace Mssc.Services.ConnectionManagement
{

  class TestIPAddress 
  {

    /**
      * The IPAddresses method obtains the selected server IP address information.
      * It then displays the type of address family supported by the server and its 
      * IP address in standard and byte format.
      **/
    private static void IPAddresses(string server) 
    {
      try 
      {
        System.Text.ASCIIEncoding ASCII = new System.Text.ASCIIEncoding();
  
        // Get server related information.
        IPHostEntry heserver = Dns.Resolve(server);

        // Loop on the AddressList
        foreach (IPAddress curAdd in heserver.AddressList) 
        {


          // Display the type of address family supported by the server. If the
          // server is IPv6-enabled this value is: InternNetworkV6. If the server
          // is also IPv4-enabled there will be an additional value of InterNetwork.
          Console.WriteLine("AddressFamily: " + curAdd.AddressFamily.ToString());
          
          // Display the ScopeId property in case of IPV6 addresses.
          if(curAdd.AddressFamily.ToString() == ProtocolFamily.InterNetworkV6.ToString())
            Console.WriteLine("Scope Id: " + curAdd.ScopeId.ToString());


          // Display the server IP address in the standard format. In 
          // IPv4 the format will be dotted-quad notation, in IPv6 it will be
          // in in colon-hexadecimal notation.
          Console.WriteLine("Address: " + curAdd.ToString());
        
          // Display the server IP address in byte format.
          Console.Write("AddressBytes: ");



          Byte[] bytes = curAdd.GetAddressBytes();
          for (int i = 0; i < bytes.Length; i++) 
          {
            Console.Write(bytes[i]);
          }                          

          Console.WriteLine("\r\n");

        }

      }
      catch (Exception e) 
      {
        Console.WriteLine("[DoResolve] Exception: " + e.ToString());
      }
    }

    // This IPAddressAdditionalInfo displays additional server address information.
    private static void IPAddressAdditionalInfo() 
    {
      try 
      {
        // Display the flags that show if the server supports IPv4 or IPv6
        // address schemas.
        Console.WriteLine("\r\nSupportsIPv4: " + Socket.SupportsIPv4);
        Console.WriteLine("SupportsIPv6: " + Socket.SupportsIPv6);

        if (Socket.SupportsIPv6)
        {
          // Display the server Any address. This IP address indicates that the server 
          // should listen for client activity on all network interfaces. 
          Console.WriteLine("\r\nIPv6Any: " + IPAddress.IPv6Any.ToString());

          // Display the server loopback address. 
          Console.WriteLine("IPv6Loopback: " + IPAddress.IPv6Loopback.ToString());
      
          // Used during autoconfiguration first phase.
          Console.WriteLine("IPv6None: " + IPAddress.IPv6None.ToString());
      
          Console.WriteLine("IsLoopback(IPv6Loopback): " + IPAddress.IsLoopback(IPAddress.IPv6Loopback));
        }
        Console.WriteLine("IsLoopback(Loopback): " + IPAddress.IsLoopback(IPAddress.Loopback));
      }
      catch (Exception e) 
      {
        Console.WriteLine("[IPAddresses] Exception: " + e.ToString());
      }
    }


    public static void Main(string[] args) 
    {
      string server = null;
    
      // Define a regular expression to parse user's input.
      // This is a security check. It allows only
      // alphanumeric input string between 2 to 40 character long.
      Regex rex = new Regex(@"^[a-zA-Z]\w{1,39}$");

      if (args.Length < 1)
      {
        // If no server name is passed as an argument to this program, use the current 
        // server name as default.
        server = Dns.GetHostName();
        Console.WriteLine("Using current host: " + server);
      }
      else
      {
        server = args[0];
        if (!(rex.Match(server)).Success)
        {
          Console.WriteLine("Input string format not allowed.");
          return;
        }
      }

      // Get the list of the addresses associated with the requested server.
      IPAddresses(server);
    
      // Get additonal address information.
      IPAddressAdditionalInfo();
    }

  }
}

[C++] 
#using <mscorlib.dll>
#using <System.dll>
using namespace System;
using namespace System::Net;
using namespace System::Net::Sockets;

/**
* The IPAddresses method obtains the selected server IP address information.
* It then displays the type of address family supported by the server and its
* IP address in standard and Byte format.
**/
void IPAddresses(String* server) {
   try {
      System::Text::ASCIIEncoding* ASCII = new System::Text::ASCIIEncoding();

      // Get server related information.
      IPHostEntry* heserver = Dns::Resolve(server);

      // Loop on the AddressList
      System::Collections::IEnumerator* myEnum = heserver->AddressList->GetEnumerator();
      while (myEnum->MoveNext()) {
         IPAddress* curAdd = __try_cast<IPAddress*>(myEnum->Current);

         // Display the type of address family supported by the server. If the
         // server is IPv6-enabled this value is: InternNetworkV6. If the server
         // is also IPv4-enabled there will be an additional value of InterNetwork.
         Console::WriteLine(S"AddressFamily: {0}", __box( curAdd->AddressFamily));

         // Display the server IP address in the standard format. In
         // IPv4 the format will be dotted-quad notation, in IPv6 it will be
         // in in colon-hexadecimal notation.
         Console::WriteLine(S"Address: {0}", curAdd);

         // Display the server IP address in Byte format.
         Console::Write(S"AddressBytes: ");

         Byte bytes[] = curAdd->GetAddressBytes();
         for (int i = 0; i < bytes->Length; i++) {
            Console::Write(bytes->Item[i]);
         }
         Console::WriteLine(S"\r\n");
      }

   } catch (Exception* e) {
      Console::WriteLine(S"->Item[DoResolve] Exception: {0}", e);
   }
}

// This IPAddressAdditionalInfo displays additional server address information.
void IPAddressAdditionalInfo() {
   try {
      // Display the flags that show if the server supports IPv4 or IPv6
      // address schemas.
      Console::WriteLine(S"\r\nSupportsIPv4: {0}", __box( Socket::SupportsIPv4));
      Console::WriteLine(S"SupportsIPv6: {0}", __box( Socket::SupportsIPv6));

      if (Socket::SupportsIPv6) {
         // Display the server Any address. This IP address indicates that the server
         // should listen for client activity on all network interfaces.
         Console::WriteLine(S"\r\nIPv6Any: {0}", IPAddress::IPv6Any);

         // Display the server loopback address.
         Console::WriteLine(S"IPv6Loopback: {0}", IPAddress::IPv6Loopback);

         // Used during autoconfiguration first phase.
         Console::WriteLine(S"IPv6None: {0}", IPAddress::IPv6None);

         Console::WriteLine(S"IsLoopback(IPv6Loopback): {0}", __box( IPAddress::IsLoopback(IPAddress::IPv6Loopback)));
      }
      Console::WriteLine(S"IsLoopback(Loopback): {0}", __box( IPAddress::IsLoopback(IPAddress::Loopback)));
   } catch (Exception* e) {
      Console::WriteLine(S"->Item[IPAddresses] Exception: {0}", e);
   }
}

int main() {
   String* args[] = Environment::GetCommandLineArgs();
   String* server;

   if (args->Length == 1)
      // If no server name is passed as an argument to this program, use the current
      // server name as default.
      server = Dns::GetHostName();
   else
      server = args[1];

   // Get the list of the addresses associated with the requested server.
   IPAddresses(server);

   // Get additonal address information.
   IPAddressAdditionalInfo();
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Namespace: System.Net

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

Assembly: System (in System.dll)

See Also

IPAddress Members | System.Net Namespace

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