通过特定网络适配器发送 HttpWebRequest

Question

我的计算机连接了两个无线网络适配器，每个适配器都连接到不同的网络。我想构建一种代理服务器，我的浏览器将连接到该代理服务器，它将从不同的适配器发送 HTTP 请求，因此网页上的加载时间会更短。 你们知道我如何决定从哪个网络适配器发送 HttpWebRequest 吗？

谢谢:)

更新

我使用了这段代码：

public static IPEndPoint BindIPEndPointCallback(ServicePoint servicePoint, IPEndPoint remoteEndPoint, int retryCount)
{
    List<IPEndPoint> ipep = new List<IPEndPoint>();
    foreach (var i in System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces())
    {
        foreach (var ua in i.GetIPProperties().UnicastAddresses)
            ipep.Add(new IPEndPoint(ua.Address, 0));
    }
    return new IPEndPoint(ipep[1].Address, ipep[1].Port);
}

private void button1_Click(object sender, EventArgs e)
{
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://whatismyip.com");
    request.ServicePoint.BindIPEndPointDelegate = new BindIPEndPoint(BindIPEndPointCallback);
    HttpWebResponse response = (HttpWebResponse)request.GetResponse();
    StreamReader sr = new StreamReader(response.GetResponseStream());
    string x = sr.ReadToEnd();
}

但是即使更改了IPEndPoint，我发送的从WhatIsMyIp获得的IP仍然是相同的..有什么帮助吗？

Answer 1

BindIPEndPointDelegate 很可能就是您想要的这里。它允许您强制特定的本地 IP 作为发送 HttpWebRequest 的端点。

Answer 2

这个例子对我有用：

using System;
using System.Net;

class Program
{
    public static void Main ()
    {
        foreach (var ip in Dns.GetHostAddresses (Dns.GetHostName ())) 
        {
            Console.WriteLine ("Request from: " + ip);
            var request = (HttpWebRequest)HttpWebRequest.Create ("http://ns1.vianett.no/");
            request.ServicePoint.BindIPEndPointDelegate = delegate {
                return new IPEndPoint (ip, 0);
            };
            var response = (HttpWebResponse)request.GetResponse ();
            Console.WriteLine ("Actual IP: " + response.GetResponseHeader ("X-YourIP"));
            response.Close ();
        }
    }
}

Answer 3

这是因为 WebRequest 使用 ServicePointManager 并且它缓存用于单个 URI 的实际 ServicePoint。因此，在您的情况下，BindIPEndPointDelegate 仅调用一次，所有后续 CreateRequest 都会重用相同的绑定接口。这是一个更底层的 TcpClient 示例，实际有效：

        foreach (var iface in NetworkInterface.GetAllNetworkInterfaces())
        {
            if (iface.OperationalStatus == OperationalStatus.Up && iface.NetworkInterfaceType != NetworkInterfaceType.Loopback)
            {
                Console.WriteLine("Interface: {0}\t{1}\t{2}", iface.Name, iface.NetworkInterfaceType, iface.OperationalStatus);
                foreach (var ua in iface.GetIPProperties().UnicastAddresses)
                {
                    Console.WriteLine("Address: " + ua.Address);
                    try
                    {
                        using (var client = new TcpClient(new IPEndPoint(ua.Address, 0)))
                        {
                            client.Connect("ns1.vianett.no", 80);
                            var buf = Encoding.UTF8.GetBytes("GET / HTTP/1.1\r\nConnection: close\r\nHost: ns1.vianett.no\r\n\r\n");
                            client.GetStream().Write(buf, 0, buf.Length);
                            var sr = new StreamReader(client.GetStream());
                            var all = sr.ReadToEnd();
                            var match = Regex.Match(all, "(?mi)^X-YourIP: (?'a'.+)$");
                            Console.WriteLine("Your address is " + (match.Success ? match.Groups["a"].Value : all));
                        }
                    }
                    catch (Exception ex)
                    {
                        Console.WriteLine(ex.Message);
                    }
                }
            }
        }