Impossible to send a packet Exception When pinging in windows mobile apps code(.net compact)

Question

I am facing this exception "Impossible to send packets" when i am pinging www.google.com in my windows mobile app code (.netcf c#). But, pinging with localhost(127.0.0.1) gives the success result.

How to get resolve from this problem?

Here is my code..

public bool PingTest()
    {
        int packet=32;

        IPHostEntry hostEnt = Dns.GetHostEntry("www.google.com");
        IPAddress ip = hostEnt.AddressList[0];

        PingOptions options = new PingOptions();
        options.Ttl = 128;
        options.DontFragment = false;

        //Debug.WriteLine("Ip address: " + ip.Address);

        Byte[] pkt= new Byte[packet];

        Ping ping = new Ping();

        try
        {
            //const string adr = "216.58.197.78";
            PingReply pingReply = ping.Send(ip, pkt, 1000, options);

            
            if (pingReply.Status == IPStatus.Success)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
        catch (Exception ex)
        {
            Debug.WriteLine("The UnHandled Exception is: " + ex.Message);

            return false;
        }

       
    }