两台外网主机之间的通信

Client端：

 

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.Net.Sockets;

namespace client
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        Socket c;
        public void Client(IPEndPoint serverIPEP)
        {
            try
            {
                c = new Socket(serverIPEP.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
                c.Connect((EndPoint)serverIPEP);
                MessageBox.Show("成功连接远程主机");
                c.Send(System.Text.Encoding.Default.GetBytes("这是一个测试信息"));
                byte[] data = new byte[1024];
                int rect = c.Receive(data);
                byte[] chat = new byte[rect];
                Buffer.BlockCopy(data, 0, chat, 0, rect);
                MessageBox.Show(System.Text.Encoding.Default.GetString(chat));

            }

            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
        private void button1_Click(object sender, EventArgs e)
        {
            Client(new IPEndPoint(IPAddress.Parse(this.IP.Text), int.Parse(this.Port.Text)));

        }
    }
}

Server端：

 

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.Net.Sockets;
using System.Threading;

namespace server
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            Control.CheckForIllegalCrossThreadCalls = false;
        }
        Thread t;
        //114.94.201.118  
        private void BeginListen()
        {
            IPHostEntry hostIP = Dns.GetHostByName(Dns.GetHostName());
            IPAddress serverIP = hostIP.AddressList[0];
            IPEndPoint iep = new IPEndPoint(serverIP, 2009);
            Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            byte[] byteMessage=new byte[1024];
            socket.Bind(iep);
            while (true)
            {
                socket.Listen(3);
                Socket newSocket = socket.Accept();
                try
                {
                    string[] IP = newSocket.RemoteEndPoint.ToString().Split(':');
                    ListViewItem li = new ListViewItem();
                    li.SubItems.Clear();
                    li.SubItems[0].Text = IP[0];
                    li.SubItems.Add(IP[1]);
                    this.listView1.Items.Add(li);
                    newSocket.Receive(byteMessage);
                    string sTime = DateTime.Now.ToShortDateString();
                    string msg = sTime + ":" + " Message from :";
                    msg += newSocket.RemoteEndPoint.ToString() + Encoding.Default.GetString(byteMessage);
                  this.textBox2.Text = msg;
                  newSocket.Send(byteMessage);
                }
                catch (Exception e)
                {
                    MessageBox.Show("与远程主机失去连接");
                }
            }
        }
      
        private void button1_Click(object sender, EventArgs e)
        {
            t = new Thread(new ThreadStart(BeginListen));
            t.Start();
        }