Unable to FTP to Fritzbox 7490 from outside the home network

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quebec

650 posts

Ultimate Geek

#223826 19-Oct-2017 09:44

I use duckdns to access Fritzbox 7490 which is working fine but can't ftp to it. Do I need to change any other settings somewhere? Looking at the activity in FileZilla looks like connections gets established but fails to retrieve the directory listing.

Status: Resolving address of khadanja.duckdns.org
Status: Connecting to xxx.xxx.xx.xxx:21...
Status: Connection established, waiting for welcome message...
Status: Initializing TLS...
Status: Verifying certificate...
Status: TLS connection established.
Status: Logged in
Status: Retrieving directory listing...
Error: Connection timed out after 60 seconds of inactivity
Error: Failed to retrieve directory listing
Status: Disconnected from server
Status: Resolving address of khadanja.duckdns.org
Status: Connecting to xxx.xxx.xx.xxx:21...
Status: Connection established, waiting for welcome message...
Status: Initializing TLS...
Status: Verifying certificate...
Status: TLS connection established.
Status: Logged in
Status: Retrieving directory listing...
Command: PWD
Response: 257 "/" is current directory.
Command: TYPE I
Response: 200 Type set to I.
Command: PASV
Response: 227 Entering Passive Mode (xxx,xxx,xx,xxx,208,10)
Command: LIST
Error: The data connection could not be established: ETIMEDOUT - Connection attempt timed out
Error: Connection timed out after 60 seconds of inactivity
Error: Failed to retrieve directory listing
Status: Disconnected from server
Status: Resolving address of khadanja.duckdns.org
Status: Connecting to xxx.xxx.xx.xxx:21...
Status: Connection established, waiting for welcome message...
Status: Initializing TLS...
Status: Verifying certificate...
Status: TLS connection established.
Status: Logged in
Status: Retrieving directory listing...
Command: PWD
Response: 257 "/" is current directory.
Command: TYPE I
Response: 200 Type set to I.
Command: PASV
Response: 227 Entering Passive Mode (xxx,xxx,xx,xxx,159,200)
Command: LIST
Error: The data connection could not be established: ETIMEDOUT - Connection attempt timed out
Error: Connection timed out after 60 seconds of inactivity
Error: Failed to retrieve directory listing

andgor

38 posts

Geek

#1886242 19-Oct-2017 12:48

You are FTPing to the Fritzbox itself?

FTP uses two TCP connections. A control/command connection and a data connection. The control connection is from the client to port 21 on the server. The data connection can be either direction (client listens and the server connects to it (active mode) or the server listens on the client connects to it (passive mode)). From your log you are encrypting the control connection and using passive mode. When doing a transfer of data (file or directory listing) the server is listening on a port (a different one to 21) and tells the client to connect to it. As it is behind a firewall an exception to be created on the firewall to allow the connection from your client to the FTP server. But as you are encrypting the control connection the firewall can't sniff the control connection to see when it has to do this and I guess the FTP server doesn't interact directly with the firewall to allow the connections.

The usual solution is to either use SFTP which uses a SSH connection on a single port/connection for everything or port forward a range of ports through to your FTP server and tell it to use those for the data connection (the PassivePorts configuration option in proftpd). I don't know if either is possible with the Fritzbox.

quebec

650 posts

Ultimate Geek

#1886320 19-Oct-2017 16:25

andgor:

You are FTPing to the Fritzbox itself?

FTP uses two TCP connections. A control/command connection and a data connection. The control connection is from the client to port 21 on the server. The data connection can be either direction (client listens and the server connects to it (active mode) or the server listens on the client connects to it (passive mode)). From your log you are encrypting the control connection and using passive mode. When doing a transfer of data (file or directory listing) the server is listening on a port (a different one to 21) and tells the client to connect to it. As it is behind a firewall an exception to be created on the firewall to allow the connection from your client to the FTP server. But as you are encrypting the control connection the firewall can't sniff the control connection to see when it has to do this and I guess the FTP server doesn't interact directly with the firewall to allow the connections.

The usual solution is to either use SFTP which uses a SSH connection on a single port/connection for everything or port forward a range of ports through to your FTP server and tell it to use those for the data connection (the PassivePorts configuration option in proftpd). I don't know if either is possible with the Fritzbox.

Works if I choose plain FTP (insecure under Encryption in FileZilla. Actually I am trying to create a free certificate for my router access site xxx.duckdns.org from https://www.sslforfree.com but when I go through the verification process through ftp it doesn't work still -

Server error 0. Make sure directory is publicly accessible through port 80. Turn off password protection temporarily if on. Ask your host if unsure about the directory or try using an FTP client or >web FTP if you do not have an FTP client to try finding it out.