Translate between FTP and SFTP protocols

[Castaglia]

There will be cases where sites wish to use SFTP on the frontend, but use FTP (e.g. to an old/legacy FTP server) on the backend. Or, vice versa, for supporting old/legacy FTP-only clients in talking to an SFTP server.

The mod_proxy module would be in a position to handle such protocol translations, as best as possible.

[mfuterko]

Hi @Castaglia. That would be great to have such a translation between the protocols. We are trying to put PorFTPd into a Kubernetes cluster and that would be way much easier with the SFTP protocol. Is it something you would prioritize? Thanks, Mike.

[Castaglia]

With support for proxying of SSH (see Issue #56), mod_proxy now has the basic building blocks needed for implementing this protocol translation feature.

Now the question is: just which protocols need to be translated to/from what? The main use cases I can envision are:

• translate from frontend SFTP to backend FTP (e.g for providing SFTP access to a legacy FTP-only server)
• translate from frontend FTP to backend SFTP (not sure where this might be useful, though?)

And then there are things like: how much do people want to support frontend SCP to a backend FTP server?

Please add/contribute your thoughts, use cases to this ticket, to help me understand what kinds of situations you face, where this protocol translation feature will be useful. Thanks!

[kdesjard]

translate from frontend FTP to backend SFTP (not sure where this might be useful, though?)

Our use case would be to support using an SFTP backend with a legacy application that is only capable of FTP.

[pedanticdan]

I also am primarily interested in translating FTPS frontend to SFTP backend, to support legacy FTP users while being able to proxy through a firewall without the weird FTP complexities.

[Castaglia]

@kdesjard @pedanticdan for your frontend FTP/FTPS use cases, would mod_proxy be used as a reverse proxy, or as a forward proxy, to the SFTP backend?

[kdesjard]

Forward, in my case.

[pedanticdan]

Reverse in my case.

Sorry I only just saw this ... upgrading to ProFTPd 1.3.8 just became a priority.