Ping! You’re It!

Here’s a quick little bit of code that will allow you to scan a subnet for available IP addresses (provided no one is blocking ICMP traffic).

You’ll need to add a reference to System.Windows.Forms to allow access to the clipboard (and mark your entry method with [STAThread].

The formatting’s terrible, but I just copy & pasted and it worked…

namespace Spike.IMCP
{
    class Program
    {
        [STAThread]
        static void Main(string[] args)
        {
            Ping pingSender = new Ping();
            List<string> available = new List<string>();
            List<string> unavailable = new List<string>();
            
            for (int i = 1; i < 255; i++)
            {
                string address = string.Format("192.168.0.{0}", i);
                PingReply reply = pingSender.Send(address,20);
                switch (reply.Status)
                {
                    case IPStatus.Success:
                        Console.WriteLine("{0} {1}ms TTL:{2}", reply.Address.ToString(), reply.RoundtripTime, "");
                        available.Add(address);
                        break;
                    default:
                        //Console.WriteLine("{0} ({1})", reply.Status, address);
                        unavailable.Add(address);
                        break;
                }


            }

            Console.WriteLine("Unavailable addresses");
            StringBuilder sb = new StringBuilder();

            foreach (string item in unavailable)
            {
                Console.WriteLine(" {0}", item);
                sb.AppendLine(item);
            }
            
            Clipboard.SetText(sb.ToString());

            Console.ReadLine();

        }
    }
}