Socket programming server and client (multiple clients can connect to the same port of a server at the same time)

Server-side code

using System; using System.Collections.Generic; using System.Text; using System.Net; using System.Net.Sockets; using System.Threading; namespace TCP signal communication { class Program { static void Main(string[] args) { try { // hold ip Address translation to instance IPAddress ipa = IPAddress.Parse("127.0.0.1"); // Listening port 8001 TcpListener mylsn = new TcpListener(ipa, 8001); // Turn on monitoring mylsn.Start(); // Output the message of successful listening Console.WriteLine(" stay 8001 Start the service , Waiting for the connection "); // Waiting to process access connection request while (true) { Socket mysock = mylsn.AcceptSocket(); Console.WriteLine(" There is a connection , The connection comes from " + mysock.RemoteEndPoint); work w = new work(); w.mysock = mysock; w.mylsn = mylsn; Thread t = new Thread(new ThreadStart(w.main)); t.Start(); } } catch { } finally { } } } public class work { public Socket mysock; public TcpListener mylsn; public void main() { // Receive client messages byte[] data = new byte[100]; mysock.Receive(data); string rt = System.Text.UTF8Encoding.UTF8.GetString(data); Console.WriteLine(rt); // Send messages to clients mysock.Send(UTF8Encoding.UTF8.GetBytes(" Send back to the client ")); // Release resources mysock.Close(); mylsn.Stop(); } } }  

Client code

using System; using System.Collections.Generic; using System.Text; using System.IO; using System.Net; using System.Net.Sockets; namespace TCP Communication client { public class Class1 { public static void Main() { // Create a new client socket TcpClient tclient = new TcpClient(); // Connect to server tclient.Connect("127.0.0.1", 8001); Console.WriteLine(" Enter the message to send "); // Read in the characters to be transmitted string str = Console.ReadLine(); // Get stream Stream stm = tclient.GetStream(); // Send string ASCIIEncoding asen = new ASCIIEncoding(); byte[] data = asen.GetBytes(str); stm.Write(data, 0, data.Length); // Accept the message returned by the server byte[] bytes = new Byte[1024]; string res = string.Empty; int length = stm.Read(bytes, 0, bytes.Length); if (length > 0) { res = Encoding.UTF8.GetString(bytes, 0, length); } Console.WriteLine(res); // Close the connection tclient.Close(); } } }  

according to TCP/IP The original intention of the designer , When mysock.Close() Command later netstat -a -n When viewing the local connection, the corresponding link status is  TIME_WAIT. The connection is automatically closed by the system .