using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
namespace ConsoleApplication2
{
    class Program
    {
        //获取外网ip的地址  http://www.ip138.com/ip2city.asp
        static void Main(string[] args)
        {
            //通过 外网服务器获取ip
            WebClient client = new WebClient();
            byte[] bytrec = client.DownloadData("http://www.ip138.com/ip2city.asp");
            string r = Encoding.GetEncoding("GB2312").GetString(bytrec);
            string reg = @"(([1-9]|([1-9]\d)|(1\d\d)|(2([0-4]\d|5[0-5])))\.)(([1-9]|([1-9]\d)|(1\d\d)|(2([0-4]\d|5[0-5])))\.){2}([1-9]|([1-9]\d)|(1\d\d)|(2([0-4]\d|5[0-5])))";
            string ip = System.Text.RegularExpressions.Regex.Match(r, reg).ToString();
            Console.Write(ip);
            Console.Read();
            
        }
    }
}
这里是我写得获取外网ip,不过我们老大让我写个更换ip代理的,在网上找了很久很没找到合适的,希望各位大侠帮帮吗吧,