Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

So here is my problem, I'm absolutely unable to connect to a FTP server, in circumstances I've never seen before. Here is the situation :

  • I get a "Connection timed out" just after the MLSD command.
  • I usually use Filezilla, under Ubuntu, but to make sure the problem isn't related to this particular client I tried a few others : gftp on ubuntu and winscp and freeftp on windows 7. All the same result.
  • Also made sure to try with Active or Passive modes. Same result.
  • At this point I would be inclined to think there is something wrong with my current network (furthermore, according to a coworker the FTP server is OK). But I did check with and I am able to get the directory listing (which I'm not able to through a FTP client).

So in the end the last thing I didn't tried is to go on another network, solution which seems would work, but wouldn't be very practical in the long run. And thus I guess there's something wrong with my router... but what could it possibly be?

Note : I did try to register and post this question on filezilla's board first... but I can't create an account with a gmail nor hotmail account. WTF?

share|improve this question
For information, we also had the MLSD command problem, but this was not a firewall issue, but too many files in the directory (more than 40 000). – Marc MAURICE Apr 22 '13 at 15:29
I had this problem too. Strangely, the issue resolved after I added the server configuration to the Site Manager and set UNIX as server type. – Emiswelt May 30 '14 at 3:34

After a long search, the solution is simple:

Go to site management, choose the site with the problem. Choose tab "Transfer Settings" and select "active instead of 'default'.

share|improve this answer

According to the FileZilla admins, your router is probably the issue (even though you probably can't do anything about it), and they're not going to fix it to fall back to LIST if MLSD times out. See:

Solution: Try Core FTP or similar. It's unlikely you'll be able to convince the stubborn FileZilla folks to add a (stupidly simple) workaround option- "fall back to LIST if MLSD times out".

Or, since it's open source, see if you or someone else can make the change and compile it yourself. I imagine if you try to submit the change to be added to the official build, they'll reject it, but perhaps we could be pleasantly surprised.

share|improve this answer
Good to know! Gnome Commander connected just fine. – styu Aug 14 '14 at 14:11
Wow, what a professional and helpful response in that FileZilla forum: "Stop using your stupid firewall then, it's not part of the FTP protocol." – basic6 Apr 18 '15 at 14:06

I found the problem in Encryption when I changed it to "Only use plain FTP (insecure)" then its working perfectly!

FileZilla is very familiar to me and I need to fight for bugs every update of it.

share|improve this answer
Afaik this question wasn't ftp client specific and wasn't windows-specific. – peterh Apr 2 '15 at 3:02
Considering disabling TLS is a bad advice. Of course that solves the issue which is caused by TLS use, but this run an insecure connection... – Yvan Jun 23 at 8:23

I fixed the problem by using a ssh tunnel through one of my personal server. I am absolutely stumped as to why this would work. I'm currently in Japan, and my server in Canada, so perhaps there is an issue with IPv6 address (even though the server says it shouldn't)...?

share|improve this answer

Just want to let people know how I got this working.

With the MLSD timeout the problem can also be in the router.

I got a new Asus router and I forwarded the ports for passive mode wrong. I have a qnap NAS and I connect on port 21 on ftp and port xxxxx:xxxxx in passive mode. In my asus router I set the port forward (virtual server) correctly now and it works again. My FTP is forwarded correctly on port 21 to my NAS IP, just standart stuff. The problem was the passive ports my NAS wanted to use also.

I did this in my port forward section (Virtual Server is it called in ASUS routers):

Service name: Whateveryoulike

Port Range: The passive ports your device will use (standart 55536:56559 for Qnap)

Local IP: The local IP of the device (something like


Protocol: Both



BOOM! We got uplink.

The problem could be something else, but this fixed my timeout and now it all works.

share|improve this answer

If you are connecting to a unix server, and it is running iptables (firewall), then check your iptables config, in /etc/sysconfig/iptable-config, for this line:


if it is blank, edit it as follows:

IPTABLES_MODULES="ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ftp"

and reload or restart iptables: service iptables reload (or restart). Now try connecting (with passive mode), and it should work without a problem.

This fixed our problem, in the office, in desktops with Windows 7/8.1, behind a NAT, and connecting with WinSCP 5.5.3 to a production server running CentOS 6.6 x86_64, Plesk 12 and ProFTPd.

You should not need to make any crazy setting in your ftp client.

Cheers, Michael.

PS: You will need SSH access for this, and root permissions.

share|improve this answer

It's preaty simple!

You must add a firewall exeption for Fillzilla (or any client you use).

(If it doesn't work, it may be something about the firewall or port forward of your router.)

PS: Changing the mode of your connection to active can be a trick, but it's not the "best practice solution". ;-)

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.