Filezilla connection - port blocked?

Question

Since this morning I am unable to make a update with many files (i try to update the piwikinstallation, requires me to upload about 24mb). After a while, filezilla gets the answer from server, that too many clients are connected.

I did not change anything which could be related to this, in the past few days, nor windows, firewall or filezilla setting. There was an windows update 2 days ago, but I already recovered it, it did not cause the problem.

The strange thing is, I set in filezilla settings, that there is only one maximum simultaneous connection allowed. I have started laptop and filezilla new several times.

This problem is not limited to the one server, on the other server I tried, I get the same error after a while.

I tried also the other client, Fileduck or what it was, the one with the yellow duck, but I think its not working also, I do not receive any errors, (it does not say anything like in filezilla) but it somehow never stop uploading.

I have Windows 7 with only the windows firewall, I also use Avast but without firewall. I have already tested to shut off the windows firewall and the firewall of our adsl router, but it did not help. I also restarted the router.

When I do the filezilla wizard test, I can get almost through if I set to obtain ip-adress from filezillasite.

Here is the log

Connecting to probe.filezilla-project.org
Response: 220 FZ router and firewall tester ready
USER FileZilla
Response: 331 Give any password.
PASS 3.7.3
Response: 230 logged on.
Checking for correct external IP address
Retrieving external IP address from http://ip.filezilla-project.org/ip.php
Checking for correct external IP address
IP 84.251.------ ie-cfb-bjb-bah
Response: 200 OK
PREP 51905
Response: 200 Using port 51905, data token 1696147081
PORT 84,251,191,107,202,193
Response: 200 PORT command successful
LIST
Response: 150 opening data connection
Response: 503 Failure of data connection.
Server sent unexpected reply.
Connection closed

Between the 150 opening and the 503 failure code are several minutes.

I have tried to use a website to check if the port is open, but I get this error:

Error: I could not see your service on 84.251.---- on port (21)
Reason: Connection timed out

So this means the port is closed? How can it be, since the both firewall were shutdown (windows firewall has filezilla in list of allowed programs anyway and the router has never made problems before, and I did not update there anything)

I tried to search on internet, if I can check these things with telnet, I have putty installed, but its long time since I had to do with this network-stuff.. Strange how quick these things get forgotten.

But anyway, how can I furthermore find out, what causes this problem? Is it really that the too many client connections are because of a firewall, which blocks the answers, so filezilla tries to connect new? or something like this?

Any help really appreciated!

Answer 1

FileZilla has an option for speed limits when sending files. I've had this option interfere with my transfers once before so try disabling it under Transfer -> Speed Limits -> Disable in the menu.

As per testing to see if you will get limited again in regards to your connection using PuTTy, launch PuTTy and select the telnet option. Put the IP of your server in the IP field and port 21 in the port field.

If you receive the banner from the server (if one is set) then great. You can also use your built in ftp client in *nix or windows.

open a terminal or command prompt and type ftp <ip address>

You will be prompted for your credentials. Once you enter them you will want to use the "send" command for Windows or "put" command for *nix to send your file to the FTP server.

It will then ask you for the local file on your machine which you will have to copy and paste / type out the full directory path if you did not change your current working directory to where the file is located.

As per testing to see if the port is closed/open in your firewall: http://www.yougetsignal.com/tools/open-ports/ check that site. If you do not trust that site, you can download a tool called Nmap to test if the port is open / closed.

If you use nmap, use nmap -p 21 <IP address> to see if the port is open or closed.

Answer 2

The problem was really on ISP side. Or more exact, on our wifi. The technican came by and changed our socket for the optical fiber. He advised us, that there are problems with wifi when many users are using it in the same house. We have about 10 wifi stations in our list.

So we tried to use ethernet when the problems occured, and with cable everything is fine. This is really strange, I never heard before that many wifi stations can disturb each other, but the wifi is working sometimes really slow, and with ethernet connected there are no problem.