IPAddress Class

Provides an Internet Protocol (IP) address.

Namespace: System.Net
Assembly: System (in system.dll)

public ref class IPAddress
/** @attribute SerializableAttribute() */ 
public class IPAddress
public class IPAddress

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

The following code example shows how to query a server to obtain the family addresses and the IP addresses it supports.

No code example is currently available or this language may not be supported.
// This program shows how to use the IPAddress class to obtain a server 
// IP addressess and related information.
import System.*;
import System.Net.*;
import System.Net.Sockets.*;
import System.Text.RegularExpressions.*;

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
            for (int iCtr = 0; iCtr < heserver.get_AddressList().length;
                iCtr++) {            
                IPAddress curAdd = heserver.get_AddressList()[iCtr];

                // 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.get_AddressFamily().ToString()));

                // Display the ScopeId property in case of IPV6 addresses.
                if (curAdd.get_AddressFamily().ToString().equals(
                        ProtocolFamily.InterNetworkV6.ToString())) {
                    Console.WriteLine(("Scope Id: " 
                        +(new Long(curAdd.get_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: ");

                ubyte bytes[] = curAdd.GetAddressBytes();
                for (int i = 0; i < bytes.length; i++) {
        catch (System.Exception e) {
            Console.WriteLine(("[DoResolve] Exception: " + e.ToString()));
    } //IPAddresses

    // 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: " 
                + System.Convert.ToString(Socket.get_SupportsIPv4()));
            Console.WriteLine("SupportsIPv6: " 
                + System.Convert.ToString(Socket.get_SupportsIPv6()));
            if (Socket.get_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): " 
                + System.Convert.ToString(IPAddress.
        catch (System.Exception e) {
            Console.WriteLine(("[IPAddresses] Exception: " + e.ToString()));
    } //IPAddressAdditionalInfo

    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).get_Success())) {
                Console.WriteLine("Input string format not allowed.");
        // Get the list of the addresses associated with the requested server.

        // Get additonal address information.
    } //main
} //TestIPAddress


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

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0