FTP服务器 能够实现监听 打开目录-In active mode FTP the client connects from a random unprivileged port (N > 1024) to the FTP server’s command port, port 21. Then, the client starts listening to port N+1 and sends the FTP command PORT N+1 to the FTP server.

Java的One-Way active measure Protocol测试代码-source code running on linux by Java used for One-Way active measure Protocol