Hit the settings button on the lower left and choose the "Network" tab. Specify your proxy there.

This was the first thing I did. In the past this worked but now I can set the proxy and it is ignored. The previous versions as well as the actual version has the problem that it doesn't remember that a proxy was set. It remembers the proxy settings itself but on every start it is set to System settings.

If you prefer the command line: /opt/Qt/MaintenanceTool --proxy http://proxyhost:8080 - or whatever the proxy port is instead of 8080.

Tried this also. This parameter seems to not exist any more. If I start it with this parameter it starts normal but ignores the setting. According to the help ( MaintenanceTool --help ) this parameter does not exist. Beside other parameters I get only this:

  --sp, --system-proxy                               Use system proxy on
                                                     Windows and Linux. This
                                                     option has no effect on
                                                     macOS. (Default)
  --np, --no-proxy                                   Do not use system proxy.

On Linux it should actually work and it does for me, also with 4.11.0. I don't know of any fundamental changes in QNetworkProxy or the IFW. Since you can pin it down to a specific version, it could be that

• somehow the upgrade has tampered with MaintenanceTool's settings file and an existing proxy setting got lost
• a local change of proxy settings got in the way
• there is a bug in 4.11

With that said, could you check you environment for any of those variables and their content?

http_proxy / HTTP_PROXY
https_proxy / HTTPS_PROXY

If they exist and IFW doesn't pick them up, we have landed a bug worth reporting under https://bugreports.qt.io

Usually I don't use this environment variables, because the browsers allow to set this in the program. To access the machines on the Intranet I don't need the proxy. Because the list of exceptions for the proxy would be large, I renounced this.

However: I tried to set this variables also, but it didn't change anything.

To make it clear: The proxy itself is working. Other apps like browsers can access the Internet over the proxy.

A.T.

Hit the settings button on the lower left and choose the "Network" tab. Specify your proxy there.
If you prefer the command line: /opt/Qt/MaintenanceTool --proxy http://proxyhost:8080 - or whatever the proxy port is instead of 8080.

I wouldn't be surprised about flaky system proxy detection on Windows, especially on corporate environments.
On Linux it should actually work and it does for me, also with 4.11.0. I don't know of any fundamental changes in QNetworkProxy or the IFW. Since you can pin it down to a specific version, it could be that

• somehow the upgrade has tampered with MaintenanceTool's settings file and an existing proxy setting got lost
• a local change of proxy settings got in the way
• there is a bug in 4.11

With that said, could you check you environment for any of those variables and their content?

http_proxy / HTTP_PROXY
https_proxy / HTTPS_PROXY

If they exist and IFW doesn't pick them up, we have landed a bug worth reporting under https://bugreports.qt.io