C#获取本机内网外网IP

using System.Net;

        //获取本地ip地址
        public String GetLocalIpAddress()
        {
            IPAddress[] names = Dns.GetHostAddresses(Dns.GetHostName());
            if (Dns.GetHostAddresses(Dns.GetHostName()).Length > 1)
                return Dns.GetHostAddresses(Dns.GetHostName())[1].ToString();
            else
                return Dns.GetHostAddresses(Dns.GetHostName())[0].ToString();
        }

<span style="white-space:pre">	</span>//获取外网ip地址
        public string GetExtenalIpAddress()
        {
            try
            {
                //从网址中获取本机ip数据
                System.Net.WebClient client = new System.Net.WebClient();
                client.Encoding = System.Text.Encoding.Default;
                string reply = client.DownloadString("http://1111.ip138.com/ic.asp");   //"http://www.ip138.com"

                //提取外网ip数据 [218.104.71.178]
                int i1 = reply.IndexOf("["), i2 = reply.IndexOf("]");
                string IP = reply.Substring(i1 + 1, i2 - 1 - i1);
                if (!IP.Equals("")) return IP;
            }
            catch (Exception) { }

            return "未获取到外网ip";
        }

C#获取本机内网外网IP

原文：http://blog.csdn.net/scimence/article/details/44408783