Are you using active or passive FTP? If you are using passive FTP to get around the problem of foreign server establishing data connection to your unprivileged port (>1023), which would probably be blocked by your firewall, then server side might have a problem. In active mode, foreign server always uses ports 21 (command) and 20 (data). In passive mode, the server uses port 21 as command port and allocates an unprivileged data port to which you (client) then connect from your unprivileged port. Since server needs to cater for many FTP connections, it may have many open unprivileged ports. To reduce the number of open ports, a firewall on the server side may be setup to allow only a *range* of unprivileged ports to be open at any one time. Also, some FTP servers can be setup to allocate only from within a range of ports. I wander what response do they send when that range is exhausted and what happens if the firewall's range and server's range do not match (e.g. server allocates a port, but firewall doesn't let it through)?
Ivica Brodaric
