What can cause PASV to fail (immediately get Error: Disconnected from server: ECONNABORTED - Connection aborted)?

[georaldc]

Don't know much about how FTP works but I've been having this issue where I need to connect to a certain server (which we have no control over) using plain FTP and the moment filezilla sends the PASV command, I immediately get disconnected. Filezilla log shows the following

- Command: PASV
- Error: Disconnected from server: ECONNABORTED - Connection aborted

If I test the server using a service like ftptest.net, I get the following

- Command: PASV
- Reply: 227 Entering Passive Mode (ip and port numbers)
- Error: Server returned unroutable private IP address in PASV reply

I would expect filezilla to use the server address in this case but it probably never even gets the chance since it gets disconnected immediately before even receiving a reply. The ftp server owner tells me that FTP works just fine on their end but I was never able to get it work on our local network (using filezilla) or on our production web server (I'm basically creating a script with PHP to send certain files via FTP but encounter similar issues the moment my script sends the passive command via PHP). One thing I noticed is if I connect to a different network, like to my phone via mobile hotspot, I am able to connect just fine and make it past the PASV command.

Would this be a problem on the client side or on the server side? The unroutable private IP address seems to suggest a server-side issue but the problems I see happen before that and switching networks fixes it. It's weird because I can connect just fine to other FTP servers using plain ftp + passive on both our local network and production web servers

[botg]

The server isn't configured correctly and there appears to be a firewall on your end of the connection that drops the connection when it receives the bad reply.