什么是我的互联网接入IP

好 啊。我写了两个方法。

它尝试使用每个本地IP连接到远程主机。

代码是草稿,所以仔细检查一下。

namespace ConsoleApplication1
{
    using System;
    using System.Collections.Generic;
    using System.Net;
    using System.Net.NetworkInformation;
    using System.Net.Sockets;

    class Program
    {
        public static List<IPAddress> GetInternetIPAddressUsingSocket(string internetHostName, int port)
        {
            // get remote host  IP. Will throw SocketExeption on invalid hosts
            IPHostEntry remoteHostEntry = Dns.GetHostEntry(internetHostName);
            IPEndPoint remoteEndpoint = new IPEndPoint(remoteHostEntry.AddressList[0], port);

            // Get all locals IP
            IPHostEntry hostEntry = Dns.GetHostEntry(Dns.GetHostName());

            var internetIPs = new List<IPAddress>();
            // try to connect using each IP             
            foreach (IPAddress ip in hostEntry.AddressList) {
                IPEndPoint localEndpoint = new IPEndPoint(ip, 80);

                bool endpointIsOK = true;
                try {
                    using (Socket socket = new Socket(localEndpoint.Address.AddressFamily, SocketType.Stream, ProtocolType.Tcp)) {
                        socket.Connect(remoteEndpoint);
                    }
                }
                catch (Exception) {
                    endpointIsOK = false;
                }

                if (endpointIsOK) {
                    internetIPs.Add(ip); // or you can return first IP that was found as single result.
                }
            }

            return internetIPs;
        }

        public static HashSet <IPAddress> GetInternetIPAddress(string internetHostName)
        {
            // get remote IPs
            IPHostEntry remoteMachineHostEntry = Dns.GetHostEntry(internetHostName);

            var internetIPs = new HashSet<IPAddress>();

            // connect and search for local IP
            WebRequest request = HttpWebRequest.Create("http://" + internetHostName);
            using (WebResponse response = request.GetResponse()) {
                IPGlobalProperties properties = IPGlobalProperties.GetIPGlobalProperties();
                TcpConnectionInformation[] connections = properties.GetActiveTcpConnections();
                response.Close();

                foreach (TcpConnectionInformation t in connections) {
                    if (t.State != TcpState.Established) {
                        continue;
                    }

                    bool isEndpointFound = false;
                    foreach (IPAddress ip in remoteMachineHostEntry.AddressList) {
                        if (ip.Equals(t.RemoteEndPoint.Address)) {
                            isEndpointFound = true;
                            break;
                        }
                    }

                    if (isEndpointFound) {
                        internetIPs.Add(t.LocalEndPoint.Address);
                    }
                }
            }

            return internetIPs;
        }


        static void Main(string[] args)
        {

            List<IPAddress> internetIP = GetInternetIPAddressUsingSocket("google.com", 80);
            foreach (IPAddress ip in internetIP) {
                Console.WriteLine(ip);
            }

            Console.WriteLine("======");

            HashSet<IPAddress> internetIP2 = GetInternetIPAddress("google.com");
            foreach (IPAddress ip in internetIP2) {
                Console.WriteLine(ip);
            }

            Console.WriteLine("Press any key");
            Console.ReadKey(true);
        }
    }
}

获取此信息的最佳方法是使用WMI,此程序输出为网络目标“0.0.0.0”注册的网络适配器的IP地址,无论出于何种目的,“不是我的网络”,即“internet”(注意:我不是网络专家,因此可能不完全正确)。

using System;
using System.Management;

namespace ConsoleApplication10
{
    class Program
    {
        static void Main(string[] args)
        {
            ManagementObjectSearcher searcher = new ManagementObjectSearcher("root\\CIMV2", 
                "SELECT * FROM Win32_IP4RouteTable WHERE Destination=\"0.0.0.0\"");

            int interfaceIndex = -1;

            foreach (var item in searcher.Get())
            {
                interfaceIndex = Convert.ToInt32(item["InterfaceIndex"]);
            }

            searcher = new ManagementObjectSearcher("root\\CIMV2",
                string.Format("SELECT * FROM Win32_NetworkAdapterConfiguration WHERE InterfaceIndex={0}", interfaceIndex));

            foreach (var item in searcher.Get())
            {
                var ipAddresses = (string[])item["IPAddress"];

                foreach (var ipAddress in ipAddresses)
                {
                    Console.WriteLine(ipAddress);
                }

            }
        }
    }
}

路由到Internet的NIC有一个网关。这种方法的好处是,您不必进行DNS查找或跳出web服务器。

/// <summary> 
/// This utility function displays all the IP addresses that likely route to the Internet. 
/// </summary> 
public static void DisplayInternetIPAddresses()
{
    var sb = new StringBuilder();

    // Get a list of all network interfaces (usually one per network card, dialup, and VPN connection) 
    var networkInterfaces = NetworkInterface.GetAllNetworkInterfaces();

    foreach (var network in networkInterfaces)
    {
        // Read the IP configuration for each network 
        var properties = network.GetIPProperties();

        // Only consider those with valid gateways
        var gateways = properties.GatewayAddresses.Select(x => x.Address).Where(
            x => !x.Equals(IPAddress.Any) && !x.Equals(IPAddress.None) && !x.Equals(IPAddress.Loopback) &&
            !x.Equals(IPAddress.IPv6Any) && !x.Equals(IPAddress.IPv6None) && !x.Equals(IPAddress.IPv6Loopback));
        if (gateways.Count() < 1)
            continue;

        // Each network interface may have multiple IP addresses 
        foreach (var address in properties.UnicastAddresses)
        {
            // Comment these next two lines to show IPv6 addresses too
            if (address.Address.AddressFamily != AddressFamily.InterNetwork)
                continue;

            sb.AppendLine(address.Address + " (" + network.Name + ")");
        }
    }

    MessageBox.Show(sb.ToString());
}

你可以用 http://www.whatismyip.org/