[Feature Request] - Implement EPSV (Extended Passive Mode)

[Brueggus]

Description

I'm trying to upload a file to an FTP server over a TLS-encrypted IPv6 connection. The upload fails with the following error message:

Error: Invalid response: [425] 425 You cannot use PASV on IPv6 connections. Use EPSV instead.

The server is powered by Pure-FTPd.

PASV works for IPv4 only, therefore it's not possible to use passive mode over IPv6 at the moment.

More info: https://www.jscape.com/blog/what-is-the-ftp/s-epsv-command-and-when-do-you-use-it

Changes

Suppaftp should use EPSV instead of PASV if required or requested by the server.

Implementation

EPSV is defined in RFC2428: https://www.rfc-editor.org/rfc/rfc2428#section-3

[veeso]

That's definitely something that should be implemented. I'm in, but it will take some time 😅

[veeso]

Hi @Brueggus,
Have you the possibility to test the feature importing suppaftp as a commit from this PR #29?

It should be enough to configure the client with

client.set_mode(Mode::ExtendedPassive);

[Brueggus]

Hey,
didn't you say it would take some time? ;)

I just tested your changes and the upload works fine now when Mode::ExtendedPassive is set.

Thanks a bunch! :)

[veeso]

Hahaha, I thought it would have been harder.

Before release though, I'm going to implement the entire RFC 2428 first