I have always been using the standard Windows10 FTP-program to upload a file to a FTP-server.
Never had problems with that till recently.
When I execute exactly the same script (or do it interactively), connecting to the server works, but the “PUT filename” initiates a PORT which is also sucessful. But after that, after a long time, I get the error “425 Can’t open data connection”.
At the server, the file which was uploaded is 0-byte long.
I have the impression this started with one of the last IPFIRE-updates.
Has something changed in IPFIRE which needs a new/different configuration to make this work again ?
The strange thing is, when I use a FTP-connection in TotalCommander and transfer the same file : no problems at all and the file is uploaded correctly.
The “425 cannot open data connection” error looks like an Active v. Passive issue with ftp. In Active, ftp will start a negotiation on port 21 and send data over port 20. In Passive mode, data is sent over a high port. That may explain why TotalCommander works (which may use PASV) but basic ftp does not.
That’s what I was thinking of and wrote “needs a new/different configuration” because I see no other reason why this problem suddenly started. Somehow port 20 was working in the past and is now blocked. Don’t the recent core-updates have something like another firewall-rules implemenation which could explain this ? Could it be Squid-related (I don’t see that anymore in the gui) ?