Echo Server using System; using System.Collections.Generic; using System.Net; using System.Net.Sockets; using System.Text; namespace EchoServer { class EchoServer { private TcpListener Server; private Int32 port = 13000; static void Main(string[] args) { EchoServer server = new EchoServer(); if (args.Length > 0) { server.port = Int32.Parse(args[0]); } server.ServerStart(); } public void ServerSt..