目前大部分家庭的上网方式都是基于PPPoE协议的，它是动态分配IP地址，以弥补IPv4地址短缺的问题（好期待IPv6啊，到时候把我家的每根筷子上都分配一个IP）。由于有时候需要切换IP地址，但是到路由的设置界面里切换比较麻烦，因此自己做了个小软件，这样就方便多了。我的路由是D-Link 504，大家根据自己的情况改动一下地址。

using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.IO;namespace ChangeIP
{class Program{static void Main(string[] args){//获取当前IPstring result = GetHttpWeb("http://192.168.0.1/info.htm");int start = result.IndexOf("wanIP");int end = result.IndexOf("subMask");result = result.Substring(start, end - start);Console.Write(result);//通过路由切换IPGetHttpWeb("http://192.168.0.1/do_cmd.htm?CMD=WAN_CON&GO=info.htm&action=4");//显示进度char[] progress ={ '|', '/', '-', '\\' };for (int i = 0; i < 10; i++){Console.Write("Changing " + progress[i % 4]);Console.Write('\r');System.Threading.Thread.Sleep(500);                }Console.WriteLine();//显示新的IPresult = GetHttpWeb("http://192.168.0.1/info.htm");start = result.IndexOf("wanIP");end = result.IndexOf("subMask");result = result.Substring(start, end - start);Console.Write(result);Console.ReadKey(true);}//读取网页public static string GetHttpWeb(string uri){HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);request.Credentials = new NetworkCredential("admin", "");//路由的用户名和密码request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";request.UserAgent = "Mozilla/5.0 (Windows; U; Windows NT 5.2; zh-CN; rv:1.9.2) Gecko/20100115 Firefox/3.6";// Get the response.HttpWebResponse response;try{response = (HttpWebResponse)request.GetResponse();}catch (Exception){throw;}// Get the stream containing content returned by the server.Stream dataStream = response.GetResponseStream();// Open the stream using a StreamReader for easy access.StreamReader reader = new StreamReader(dataStream, Encoding.GetEncoding("GB2312"));// Read the content.string rsp = reader.ReadToEnd();// Cleanup the streams and the response.reader.Close();dataStream.Close();response.Close();request.Abort();return rsp;}}
}