pingreply的send方法取不到IP地址

[lg910046771]

我用PingReply对指定IP测试，结果objPingreply 拿不到地址，但是我把地址改成127.0.0.1就没问题 。
请各位大牛指教！

 public static bool testconn(string host)
        {
            try
            {
                host = "192.188.1.20";
                Ping objPingsender = new Ping();
                PingOptions objPingOptions = new PingOptions();
                objPingOptions.DontFragment = true;
                string data = "";
                byte[] buffer = Encoding.UTF8.GetBytes(data);
                int iTimeout = 120;
                PingReply objPingreply = objPingsender.Send(host, iTimeout, buffer, objPingOptions);
                string strInfo = objPingreply.Status.ToString();
                if (strInfo == "Success")
                {
                    return true;
                }
                else
                {
                    return false;
                }
            }
            catch(Exception)
            {
                return false;
            }
            
        }

[lg910046771]

[lg910046771]

刚发现图片插到代码里去了，我说咋没图