Using ping in c#

When I Ping a remote system with windows it says there is no reply, but when I ping with c# it says success. Windows is correct, the device is not connected. Why is my code able to successfully ping when Windows is not?

Here is my code :

Ping p1 = new Ping();
PingReply PR = p1.Send("192.168.2.18");
// check when the ping is not success
while (!PR.Status.ToString().Equals("Success"))
{
    Console.WriteLine(PR.Status.ToString());
    PR = p1.Send("192.168.2.18");
}
// check after the ping is n success
while (PR.Status.ToString().Equals("Success"))
{
    Console.WriteLine(PR.Status.ToString());
    PR = p1.Send("192.168.2.18");
}

using System.Net.NetworkInformation;    

public static bool PingHost(string nameOrAddress)
{
    bool pingable = false;
    Ping pinger = null;

    try
    {
        pinger = new Ping();
        PingReply reply = pinger.Send(nameOrAddress);
        pingable = reply.Status == IPStatus.Success;
    }
    catch (PingException)
    {
        // Discard PingExceptions and return false;
    }
    finally
    {
        if (pinger != null)
        {
            pinger.Dispose();
        }
    }

    return pingable;
}

Using ping in C# is achieved by using the method Ping.Send(System.Net.IPAddress), which runs a ping request to the provided (valid) IP address or URL and gets a response which is called an Internet Control Message Protocol (ICMP) Packet. The packet contains a header of 20 bytes which contains the response data from the server which received the ping request. The .Net framework System.Net.NetworkInformation namespace contains a class called PingReply that has properties designed to translate the ICMP response and deliver useful information about the pinged server such as:

• IPStatus: Gets the address of the host that sends the Internet Control Message Protocol (ICMP) echo reply.
• IPAddress: Gets the number of milliseconds taken to send an Internet Control Message Protocol (ICMP) echo request and receive the corresponding ICMP echo reply message.
• RoundtripTime (System.Int64): Gets the options used to transmit the reply to an Internet Control Message Protocol (ICMP) echo request.
• PingOptions (System.Byte[]): Gets the buffer of data received in an Internet Control Message Protocol (ICMP) echo reply message.

The following is a simple example using WinForms to demonstrate how ping works in c#. By providing a valid IP address in textBox1 and clicking button1, we are creating an instance of the Ping class, a local variable PingReply, and a string to store the IP or URL address. We assign PingReply to the ping Send method, then we inspect if the request was successful by comparing the status of the reply to the property IPAddress.Success status. Finally, we extract from PingReply the information we need to display for the user, which is described above.

    using System;
    using System.Net.NetworkInformation;
    using System.Windows.Forms;

    namespace PingTest1
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
            }

            private void button1_Click(object sender, EventArgs e)
            {
                Ping p = new Ping();
                PingReply r;
                string s;
                s = textBox1.Text;
                r = p.Send(s);

                if (r.Status == IPStatus.Success)
                {
                    lblResult.Text = "Ping to " + s.ToString() + "[" + r.Address.ToString() + "]" + " Successful"
                       + " Response delay = " + r.RoundtripTime.ToString() + " ms" + "\n";
                }
            }

            private void textBox1_Validated(object sender, EventArgs e)
            {
                if (string.IsNullOrWhiteSpace(textBox1.Text) || textBox1.Text == "")
                {
                    MessageBox.Show("Please use valid IP or web address!!");
                }
            }
        }
    }

Imports System.Net.NetworkInformation


Public Function PingHost(ByVal nameOrAddress As String) As Boolean
    Dim pingable As Boolean = False
    Dim pinger As Ping
    Dim lPingReply As PingReply

    Try
        pinger = New Ping()
        lPingReply = pinger.Send(nameOrAddress)
        MessageBox.Show(lPingReply.Status)
        If lPingReply.Status = IPStatus.Success Then

            pingable = True
        Else
            pingable = False
        End If


    Catch PingException As Exception
        pingable = False
    End Try
    Return pingable
End Function