using System;



using System.Collections.Generic;



using System.ComponentModel;



using System.Data;



using System.Drawing;



using System.Linq;



using System.Text;



using System.Windows.Forms;



using System.Net.Sockets;



namespace CSharpCheckingOnlineAvailabilityIPPort



{



    public partial class Form1 : Form



    {



        public Form1()



        {



            InitializeComponent();



        }



        private void btn_CheckServer_Click(object sender, EventArgs e)



        {



            TcpClient logonServer = new TcpClient();



            try



            {



                logonServer.Connect("127.0.0.1", 80); //this is just your loop back and checking to see if port 80 is open swap out for whatever you want



            }



            catch (Exception ex)



            {



             



            }



            if (logonServer.Connected)



                this.Text = "Connected";



            else



                this.Text = "Not connected";



            logonServer.Close();



   



        }



    }



}