它的简单。试一试:

var remoteIpAddress = Request.HttpContext.Connection.RemoteIpAddress;

就这样吧!)

到目前为止，所有的响应都考虑了非标准化但非常常见的X-Forwarded-For报头。有一个标准化的转发头，它有点难以解析。一些例子如下:

Forwarded: for="_gazonk"
Forwarded: For="[2001:db8:cafe::17]:4711"
Forwarded: for=192.0.2.60;proto=http;by=203.0.113.43
Forwarded: for=192.0.2.43, for=198.51.100.17

我已经编写了一个类，在确定客户端的IP地址时考虑这两个头。

using System;
using System.Web;

namespace Util
{
    public static class IP
    {
        public static string GetIPAddress()
        {
            return GetIPAddress(new HttpRequestWrapper(HttpContext.Current.Request));
        }

        internal static string GetIPAddress(HttpRequestBase request)
        {
            // handle standardized 'Forwarded' header
            string forwarded = request.Headers["Forwarded"];
            if (!String.IsNullOrEmpty(forwarded))
            {
                foreach (string segment in forwarded.Split(',')[0].Split(';'))
                {
                    string[] pair = segment.Trim().Split('=');
                    if (pair.Length == 2 && pair[0].Equals("for", StringComparison.OrdinalIgnoreCase))
                    {
                        string ip = pair[1].Trim('"');

                        // IPv6 addresses are always enclosed in square brackets
                        int left = ip.IndexOf('['), right = ip.IndexOf(']');
                        if (left == 0 && right > 0)
                        {
                            return ip.Substring(1, right - 1);
                        }

                        // strip port of IPv4 addresses
                        int colon = ip.IndexOf(':');
                        if (colon != -1)
                        {
                            return ip.Substring(0, colon);
                        }

                        // this will return IPv4, "unknown", and obfuscated addresses
                        return ip;
                    }
                }
            }

            // handle non-standardized 'X-Forwarded-For' header
            string xForwardedFor = request.Headers["X-Forwarded-For"];
            if (!String.IsNullOrEmpty(xForwardedFor))
            {
                return xForwardedFor.Split(',')[0];
            }

            return request.UserHostAddress;
        }
    }
}

下面是我用来验证我的解决方案的一些单元测试:

using System.Collections.Specialized;
using System.Web;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace UtilTests
{
    [TestClass]
    public class IPTests
    {
        [TestMethod]
        public void TestForwardedObfuscated()
        {
            var request = new HttpRequestMock("for=\"_gazonk\"");
            Assert.AreEqual("_gazonk", Util.IP.GetIPAddress(request));
        }

        [TestMethod]
        public void TestForwardedIPv6()
        {
            var request = new HttpRequestMock("For=\"[2001:db8:cafe::17]:4711\"");
            Assert.AreEqual("2001:db8:cafe::17", Util.IP.GetIPAddress(request));
        }

        [TestMethod]
        public void TestForwardedIPv4()
        {
            var request = new HttpRequestMock("for=192.0.2.60;proto=http;by=203.0.113.43");
            Assert.AreEqual("192.0.2.60", Util.IP.GetIPAddress(request));
        }

        [TestMethod]
        public void TestForwardedIPv4WithPort()
        {
            var request = new HttpRequestMock("for=192.0.2.60:443;proto=http;by=203.0.113.43");
            Assert.AreEqual("192.0.2.60", Util.IP.GetIPAddress(request));
        }

        [TestMethod]
        public void TestForwardedMultiple()
        {
            var request = new HttpRequestMock("for=192.0.2.43, for=198.51.100.17");
            Assert.AreEqual("192.0.2.43", Util.IP.GetIPAddress(request));
        }
    }

    public class HttpRequestMock : HttpRequestBase
    {
        private NameValueCollection headers = new NameValueCollection();

        public HttpRequestMock(string forwarded)
        {
            headers["Forwarded"] = forwarded;
        }

        public override NameValueCollection Headers
        {
            get { return this.headers; }
        }
    }
}

就像别人说的，你不可能做到你所要求的。如果你描述一下你想要解决的问题也许有人可以帮你?

如。

您是否试图唯一地标识您的用户? 您是否可以使用cookie或会话ID来代替IP地址?

Edit The address you see on the server shouldn't be the ISP's address, as you say that would be a huge range. The address for a home user on broadband will be the address at their router, so every device inside the house will appear on the outside to be the same, but the router uses NAT to ensure that traffic is routed to each device correctly. For users accessing from an office environment the address may well be the same for all users. Sites that use IP address for ID run the risk of getting it very wrong - the examples you give are good ones and they often fail. For example my office is in the UK, the breakout point (where I "appear" to be on the internet) is in another country where our main IT facility is, so from my office my IP address appears to be not in the UK. For this reason I can't access UK only web content, such as the BBC iPlayer). At any given time there would be hundreds, or even thousands, of people at my company who appear to be accessing the web from the same IP address.

当你在写服务器代码时，你永远不能确定你看到的IP地址指的是什么。一些用户喜欢这种方式。有些人故意使用代理或VPN来进一步混淆你。

当你说你的机器地址与StackOverflow上显示的IP地址不同时，你是如何找到你的机器地址的?如果您只是使用ipconfig或类似的工具在本地查找，我希望由于我上面概述的原因它会有所不同。如果你想再次确认外界的看法，可以看看whatismyipaddress.com/。

这个关于NAT的维基百科链接将为您提供一些背景知识。

你可以使用:

System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName()).AddressList.GetValue(0).ToString();

如果是c#这样看，是很简单的

string clientIp = (Request.ServerVariables["HTTP_X_FORWARDED_FOR"] ?? 
                   Request.ServerVariables["REMOTE_ADDR"]).Split(',')[0].Trim();

它的简单。试一试:

var remoteIpAddress = Request.HttpContext.Connection.RemoteIpAddress;

就这样吧!)