I cannot connect with FileZilla, but I do with another program

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OtherJules
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I cannot connect with FileZilla, but I do with another program

#1 Post by OtherJules » 2020-07-30 07:25

I'm facing this condition:
I'm trying to set up FileZilla and I use Network configuration wizard. What I get with my ordinary settings is:
Connecting to probe.filezilla-project.org
Connection established, waiting for welcome message.
Response: 220 FZ router and firewall tester ready
USER FileZilla
Response: 331 Give any password.
PASS 3.49.1
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 <my external IP>
Response: 200 OK
PREP 14202
Response: 200 Using port 14202, data token 1088669864
PORT <other external IP>,122
Response: 200 PORT command successful
LIST
Response: 150 opening data connection
The Wizard then remains like this until I cancel it.

I found a setting in my router (my ISP is a cable company and the router's brand is Arris) to disable the firewall. If I do that, then the Network configuration wizard gives this result:
Connecting to probe.filezilla-project.org
Connection established, waiting for welcome message.
Response: 220 FZ router and firewall tester ready
USER FileZilla
Response: 331 Give any password.
PASS 3.49.1
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 <my external IP>
Response: 200 OK
PREP 1638
Response: 200 Using port 1638, data token 428161363
PORT <same IP as above>,102
Response: 200 PORT command successful
LIST
Response: 150 opening data connection
Response: 503 Failure of data connection.
Server sent unexpected reply.
Connection closed
With FileZilla for this server I get this:
Status: Resolving address of <server name>
Status: Connecting to <server IP>:21...
Status: Connection established, waiting for welcome message...
Status: Insecure server, it does not support FTP over TLS.
Status: Server does not support non-ASCII characters.
Status: Logged in
Status: Retrieving directory listing...
Command: PWD
Response: 257 "<server directory>" is current directory.
Command: TYPE I
Response: 200 Type set to I.
Command: PASV
Response: 227 Entering Passive Mode (<server IP as above>,209,10)
Command: LIST
Error: Connection timed out after 20 seconds of inactivity
Error: Failed to retrieve directory listing
I increased the Timeout setting, but with no success.

ftptest.net results in the follwing:
Timeouts are usually caused by some router and/or firewall that is interrupting the connection.
Try uninstalling all firewalls and plug your computer directly into your modem, thus bypassing the router."
Disabling the Windows Defender firewall makes no difference.

The weirdest of all is that

The weird thing is if I use Directory Opus to access a particular FTP server that I'm interested in, I do get connected.
I also get connected to the server in question using WS FTP Pro (trial).

I did read the Wiki on network settings and I also searched the forum about "150 opening data connection", but unfortunately I didn't find anything comparable to my case.

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boco
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Re: I cannot connect with FileZilla, but I do with another program

#2 Post by boco » 2020-07-30 10:56

First, the always tests Active (PORT) mode, whereas, for server connections, the much more firewall-friendly Passive (PASV) mode is used. For connections to most FTP servers, the test is therefore not really relevant.
Furthermore, as you have a Cable connection, it is probably a DualStack Lite (DS-Lite) one. You usually have a public IPv6 address, but no real public IPv4 address. In this environment, neither the test nor any Active (PORT) connection will ever succeed, for IPv4 (because of Double NAT). The unknown IPv4 you are seeing is the one of the server wrapping IPv4 traffic into IPv6 packets. You cannot run servers accessible over IPv4 in this config.

As for the server connection, please test that server using our https://ftptest.net testing facility (use the Plain FTP setting). If the test fails, the server is at fault.
### BEGIN SIGNATURE BLOCK ###
No support requests per PM! You will NOT get any reply!!!
FTP connection problems? Do yourself a favor and read Network Configuration.
FileZilla connection test: https://filezilla-project.org/conntest.php
### END SIGNATURE BLOCK ###

OtherJules
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Re: I cannot connect with FileZilla, but I do with another program

#3 Post by OtherJules » 2020-07-30 11:41

Thank you for the information and the advice. Is there a way to check if my router is a DualStack Lite?
I did the test using https://ftptest.net and I already noted the result in my first posting.

The question in my mind remains why or how does some other software (Directory Opus and WS FTP Pro) connect to the server given some apparent limitations of my router?

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Re: I cannot connect with FileZilla, but I do with another program

#4 Post by botg » 2020-07-31 08:10

Check which IP address is assigned to you by your ISP. If it's a private IP address, you are behind carrier NAT.

Got a log from this other software?

OtherJules
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Re: I cannot connect with FileZilla, but I do with another program

#5 Post by OtherJules » 2020-07-31 12:01

In the router settings I see DHCP enabled and an IP address beginning with 185.7. At http://www.whatsmyip.org I see the same IP numbers.

I discovered the DS-Lite that boco mentioned! It says "DS-Lite enables IPV4 to tunnel through an IPV6 AFTR (Address Family Transition Router). Set these fields as your Internet Service Provider recommends and click the Apply button". The setting is not enabled though.

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boco
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Re: I cannot connect with FileZilla, but I do with another program

#6 Post by boco » 2020-07-31 22:44

Yeah, that DS-Lite thingy was a red herring. Your IP seems to be associated to ISP "Cyprus Nicosia". You also did not post here with an IPv6, so, you probably have none.

Could you fancy a log from a working client, as @botg requested?
### BEGIN SIGNATURE BLOCK ###
No support requests per PM! You will NOT get any reply!!!
FTP connection problems? Do yourself a favor and read Network Configuration.
FileZilla connection test: https://filezilla-project.org/conntest.php
### END SIGNATURE BLOCK ###

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