[wellylug] Advice on FTP access from Debian.

[Pete Black]

You'll need to set your FTP client to use 'PASSIVE' mode - the FTP 
protocol is a bit of an odd duck in that in it's 'ACTIVE' variant it 
relies on the ability for the server to connect directly to the client 
to negotiate ports - this is not possible behind a NAT without special 
treatment inside iptables - can be done with the FTP NAT modules though.

Short answer- set FTP client to PASSIVE and you should be fine.

-Pete

>I use Debian Woody on machines on a LAN with connection to the outside 
>network via a dial up line. This connection is managed by a 
>router/firewall/NAT using Freesco.
>To update some components, I went to use FTP to an outside server and it 
>failed. On closer investigation, my local machine will interact correctly 
>with local servers but not with outside ones. It will connect to a remote 
>FTP server, get a request for user and password and complete that. I can 
>issue 'cd' commands and it will work, but 'ls' and 'get' commands fail 
>with messages about 'invalid PORT command'. I had thougth this was to do 
>with the data channel not getting through the firewall/NAT, but my son 
>said he could use FTP to outside servers using Windows and Dos. This I 
>confirmed, so it must be somthing within my Debian machine setup.
>It is now embarrassing to be told by my son that his Windows machine will 
>do this while Linux will not and so it needs to be fixed. Could anyone 
>offer guidance on what to look for? 
>regards
>Peter Davenport
>
>
>  
>