ftp客户端c++编程FTP协议将使用两条单独的TCP连接，一条专用于发送FTP命令，另一条则专用于传递数据。初始建立连接时，服务器在21号端口上接收来自客户端的命令连接。-ftp client c programming FTP will use two separate TCP connection, a dedicated FTP to send orders, and the other one is dedicated to data transfer. The initial establishment of connection, the server port in the 21st receive from the client orders connectivity.