PING打つ

using System.Net.NetworkInformation;

        public Boolean ping(String serverAddr)
        {
            try
            {
                Ping p = new Ping();
                PingReply reply = p.Send(serverAddr);
                p.Dispose();
                if (reply.Status == IPStatus.Success)
                {
                    return true;
                }
            }
            catch(Exception ex)
            {
                trace(ex.Message);
            }
            return false;
        }