Scenario: Intranet with Internet access via HTTP proxy and local FTP servers.
Operating System: openSUSE Tumbleweed 20230613
KDE Plasma Version: 5.27.5
KDE Frameworks Version: 5.107.0
Qt Version: 5.15.9
For years I have been using Plasma on a corporate intranet where HTTP authentication is required to access the Internet. Windows domain authentication is required to access shared folders on domain computers, using the SMB protocol. An important detail here is that FTP access is to local servers INSIDE the intranet, not to servers outside, i.e. Internet access is not required for FTP.
For years, I got to work all fine doing configuring the system proxy and the KDE proxy (as you know, they are independent) to use HTTP(S) proxy.
The problem with this configuration was that KDE applications, such as Dolphin, when making an FTP connection, would try to use the proxy, so it would eventually fail. The workaround I had to find years ago, is to create a PAC file and use it only in the KDE proxy configuration (like I need to do in Firefox). In that PAC file, I put that if the path does NOT contain HTTP://, proxy is NOT required. It has always worked without further problems (and I don’t know if there is an easier way to do it, which would be wonderful).
However, for a few months now, every time I upgrade Plasma and Frameworks, Dolphin and even Krusader are unable to continue accesing the local FTP seervers and I have to downgrade to the previous system snapshot to be able to continue working. I try every 3 weeks or so to perform an update and check again if I have FTP access to the local servers, in case it is a one-off bug, but as of today (7 May 2024) any update breaks normal FTP access.
In this regard, I have verified that it happens even with the latest LIVE versions of Tumbleweed (configuring proxy as in my real installed system).
For me it is ESSENTIAL to continue to be able to access these servers with FTP. In the meantime, I cannot upgrade.
And it’s clear to me that it must be a KDE problem, because if I use the CAJA file manager to access these servers, it works!!! But of course, CAJA doesn’t offer me all the possibilities that Dolphin and Krusader do, so it’s a “patch” and not a solution to the problem.
I created a bug in KDE, but nobody has been interested in the problem, so I ask the community in case there is someone reading here who has the same scenario and the solution to the problem.
Thanks for reading
UPDATE: This issue about proxy behaviour en Plasma was reported years ago.
https://bugs.kde.org/show_bug.cgi?id=477081