Active FTP - Somtimes it does, sometimes it does not work

[Remco]

Hi All,
Using ProFTP with Slackware, I do have some troubles.
Passive FTP, works all the time when applicable.
Active FTP fails with certain connections. I can login to the FTP server, though I can't do a dir-listing or file transfer. In this case, I tried an FTP client on my local machine (WXP) connecting to the very same FTP server and it works.
I don't understand. Can anybody give me some clues about where to look for a solution?
Thanks!

[stonki]

Hi All,
Using ProFTP with Slackware, I do have some troubles.
Passive FTP, works all the time when applicable.
Active FTP fails with certain connections. I can login to the FTP server, though I can't do a dir-listing or file transfer. In this case, I tried an FTP client on my local machine (WXP) connecting to the very same FTP server and it works.
I don't understand. Can anybody give me some clues about where to look for a solution?
Thanks!

active FTP is using Port 20. Is this blocked by a Firewall ?

cu
stonki

[Anonymous]

Using the same Linux machine to FTP to another FTP server does work with Active FTP. Port 20 isn't blocked by the firewall.....