Error: Critical error: Could not connect to server while attempting to connect Server

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henry.revina
500 Command not understood
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Error: Critical error: Could not connect to server while attempting to connect Server

#1 Post by henry.revina » 2019-05-23 11:49

Hi, since I am new to FileZilla, FTP, and Server (Finance major) please forgive if the question is dumb.. Looking for the solution but unsuccessful.

So my office moved to a new destination. Before we used FTP server with our local host just fine with our client's connection. I have open port 21 on the router:

Status: Connecting to xx.xxx.xx.113:21...
Status: Connection established, waiting for welcome message...
Status: Insecure server, it does not support FTP over TLS.
Command: USER henry@revina
Response: 331 Enter PASS command
Command: PASS *********
Response: 550 Permission denied
Error: Critical error: Could not connect to server


I guess there must be something wrong with the router new set-up (the internet provider technician reset the router) - our router is Draytek Vigor 2925

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botg
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Re: Error: Critical error: Could not connect to server while attempting to connect Server

#2 Post by botg » 2019-05-23 12:36

The server you are connecting to isn't FileZilla Server. Could this be the built-in FTP server of the router you are connecting to?

henry.revina
500 Command not understood
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Last name: Le

Re: Error: Critical error: Could not connect to server while attempting to connect Server

#3 Post by henry.revina » 2019-05-23 15:01

Hi @botg, thanks for your prompt reply -

seems weird - because we used this FTP server for file transfer purpose with our clients before.
Moving to the new office, - I thought the issue must be some firewall of the router - the external IP is still the same.
The port 21 is opened - checked at www.yougetsignal.com
I got some problems when checking with FTPtester.net:
Status: Resolving address of 14.xxx.xxx.113

Status: Connecting to 14.xxx.xxx.113

Warning: The entered address does not resolve to an IPv6 address.

Status: Connected, waiting for welcome message...

Reply: 220 FTP version 1.0

Command: CLNT https://ftptest.net on behalf of 1.55.xxx.56

Reply: 502 Command not yet implemented

Command: AUTH TLS

Error: Connection got closed prematurely

I have indeed configured some parts trying to open up firewall for FTP with in ISS Manager from from our local Microsoft Server 2012. Maybe something wrong with my configuration?

Thanks in advance,

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boco
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Re: Error: Critical error: Could not connect to server while attempting to connect Server

#4 Post by boco » 2019-05-24 01:40

That is not FileZilla Server. You seem to have a rogue FTP server running.
### 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.
All FileZilla products fully support IPv6. http://worldipv6launch.org
### END SIGNATURE BLOCK ###

henry.revina
500 Command not understood
Posts: 4
Joined: 2019-05-23 11:36
First name: Henry
Last name: Le

Re: Error: Critical error: Could not connect to server while attempting to connect Server

#5 Post by henry.revina » 2019-05-24 02:31

Hi Boco,

Thanks for pointing out!

Do you think re-installing the FileZilla Server should fix the issue here?

Thanks

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boco
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Re: Error: Critical error: Could not connect to server while attempting to connect Server

#6 Post by boco » 2019-05-24 04:02

No, won't do any good by itself. You must find out what other FTP server is either running on port 21 on the server machine, or running in front of the server machine (maybe in the router). Start by checking if FileZilla Server issues an error message (port 21 in use). If yes, the rogue runs on the same machine, as sockets (IP:port) cannot be shared. In most cases, the server machine has the MS IIS software feature running, which includes IIS FTP server.

If not, the problem is in the network. In this case, you should be able to contact FileZilla Server normally from the same machine, and the issue is only with people from "outside". Many routers with NAS functionality can run an FTP server themselves, blocking the FTP port. Some even have it enabled and exposed as a remote maintenance feature (security vulnerability in my eyes).
### 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.
All FileZilla products fully support IPv6. http://worldipv6launch.org
### END SIGNATURE BLOCK ###

henry.revina
500 Command not understood
Posts: 4
Joined: 2019-05-23 11:36
First name: Henry
Last name: Le

Re: Error: Critical error: Could not connect to server while attempting to connect Server

#7 Post by henry.revina » 2019-05-24 04:38

Fixed this! Thank you Boco!
By accident/naiveness - I set up the private IP as the public IP of the Internet, instead of the private IP of the localhost server.

Thank you very much! Glad to be a part of the community!

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