If your server is behind a firewall or router you will need to allow the relevant ports for the FTP server through. The ports that must be configured for firewalls and routers include port 21 (standard FTP port) and port 990 (for implicit SSL). If you have changed these default port values on your FTP server then you should forward your port values instead. When FTP clients are using PASV mode for files transfers, the FTP server needs to be able to open additional ports. Therefore you must also forward ports 1024 - 5000 through any firewalls and routers. If you have enabled and set a PASV port range for the FTP server (see the
General Settings page for more information), then you will need to forward those port values instead. If the FTP server is behind a router then it is always a good idea to enter the router's IP into the FTP server. This will ensure that PASV mode transfers are negotiated to the correct IP for 'over the Internet' transfers.