Title: +038=360.000-OU045T_02-PCD2.m4160 PLS SBC - File system Manual.pdf
In active mode FTP the client connects from a random unprivileged port (N > 1023) 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. The server will then con- nect back to the client‘s specified data port from its local data port, which is port 20.This constellation is not foreseen in commonly used firewalls implemented in e.g. ADSL routers (on the client side). The configuration of such a specific firewall requires specialized knowledge and can not be covered in this manual. Please contact your network administrator for further information and the configuration of your firewall.3-214File system management using CGI calls4.1Introduction