This sounds like the same problem I am experiencing. And I think the cause is the router/NAT device not handling passive mode commands correctly. A workaround involves using active mode on the client side, telling the client what ports to use, and then configuring the firewall on the client side to forward a specific port range to the client. I tested this and it works. But this workaround is not for everyone, as it requires you to configure each client and client side firewall, which may not be possilbe. So changing to an FPT-aware router that knows how to handle those passive mode commands may be the only answer for those who need many clients to accesss their FZ server.
For more info on this problem, refer to the "FTP and NAT Devices" section of this Wikipedia page on FTP ( http://en.wikipedia.org/wiki/File_Transfer_Protocol
), and "The Firewall Problem" section of this FTPS page may also be helpful ( http://en.wikipedia.org/wiki/FTPS
). Or you can probably find more info by googling "passive mode problem".
I'm not sure if this helps with the problem discussed in this thread, so I will post a new thread for this subject. The Filezilla Configuration Guide doesn't touch on this issue, but it should. I am using a very common router, Linksys WRT54G, so I'm sure there are many people having this same issue with this router or others.