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;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string ipadres = textBox1.Text + "." + textBox2.Text + "." + textBox3.Text + ".";

            for (int i = 1; i <= 255; i++)
            {
                              
                if (IsOnline(ipadres+i))
                {
                    textBox5.AppendText("Het adres " + (ipadres+i) + " is geldig\n");
                }
                else
                {
                    textBox5.AppendText("Het adres " + (ipadres+i) + " is ongeldig\n");

                }

            }                                     
            
        }

        private static bool IsOnline(string naamOfAdres)
        {
            System.Net.NetworkInformation.Ping ping = new System.Net.NetworkInformation.Ping();
            return (ping.Send(naamOfAdres, 1000, new byte[20]).Status == System.Net.NetworkInformation.IPStatus.Success);

        }
    }
}