Cannot configure wrt54gs v6 router for use with filezilla FTP client

Question

I am new to working with FTP and very rusty on networking in general.  I just downloaded filezilla to create a FTP client on my desktop.  When I run their wizard, it says the connection is tainted by my router.  All the forums for filezilla say I need to configure my router to allow traffic on either port 21 (ftp) or a range of ports ( they suggest 50000 to 50100).
Please let me know what I need to do to make this work
thanks in advance
ldygunner

Answer 1

To answer your other questions, the tutorials have it all wrong. What they really need to explain, but fail to do so, is that the only situation where a FTP client would need to use active mode (the PORT command) is where the FTP server can't accept inbound connections on arbitrary port numbers. But that's a pathological case anyway: the FTP server can always accept connections on some well defined set of port numbers, to keep its own local firewall or NAT router happy. Consequently, there is really no need at all for a FTP client system to open up any ports to support active mode, rather than always operate in passive mode (as browsers do.)
The fact of the matter is that if passive mode works in a browser for you, it will work for Filezilla also.
And the configuration tests it runs are brain damaged. Even though the wizard recommends passive mode, it never tests for it. And it doesn't really test active mode either. What it really tests is whether anything between the client and the server is "transparently" translating IP addresses and port numbers. Such a test is broken, because the mere fact of port numbers being rewritten in TCP packets is irrelevant to whether PORT (active mode) will succeed or fail.
For completeness, in case someone decides to get pedantic, there is a case where a FTP client system would need the active mode PORT command to work, but that case is now of historical interest only. It's a scenario that FTP servers no longer support, for security reasons. (What is it? When the FTP client is operating as a controller to remotely transfer files between two servers: it tells one server to use passive mode, and sends the address/port it gets to the other server in active mode, which in theory would make the second server open a connection to the first. This, in fact, is why two modes, active and passive, were originally defined in the FTP standard!)  And it still wouldn't need open ports on the client system.
Message Edited by arayq2 on 10-19-2008 09:12 PM