I just tried to register an email account with protonmail. Using the fedora VM I could not register and got a message that I was blocked because of SPAM. Changing the IP address did not help either. Also I did not register any accounts there. But switching to the debian vm I could register.
Is Qubes detected and blocked by websites depending on the config? Is it possible?
Do you use a VPN? or exit through TOR? Because that is usually detected and some sites dislike it.
In other words, it is not QubesOS that gets detected, the block is applied to your IP address as seen by the website.
All websites, including proton.me, can do anything. They can block you based on IP, fingerprint, and quite often by useragent that is probably different for Fedora and Debian templates, and in both cases it probably looks suspicious (not as original GNU/Linux distro).
I advise to use some addon for useragent change (in firefox, of course) and look like windows 10/11 firefox or chrome to websites.
If you still have problems after that, it will in most cases mean your internet connection is temporary banned by the server or some ban-list they utilize. Small websites like proton are more commonly reject users.
Just go ask Proton user support if they block signups based on more than just IPs now. They do not have any vested interest in hiding the information from you or making a grand conspiracy out of it.
In past their policy has solely been based on IP addresses and they’ve been very upfront about the metadata they associate with account signups off of each IP address like this. They are not trying to dox you or discourage Qubes users from making Proton accounts.
Setting aside the matter that Proton has given you absolutely no reason to suspect that you were discriminated against for using Qubes OS in particular, a browser fingerprint is just derived from all the information from literally everything a web page can grab from your browser and send back. As a technological threat it’s a constantly moving target as web standards evolve and browsers too. You mentioned moving between Fedora and Debian, but didn’t mention which browsers you used, what state they were in, or anything that would provide any insight into how they might contribute to fingerprinting, not to mention the cryptic mention of just trying two different IPs but not noting whether or not you tried both your Fedora and Debian setups against the same IPs.
If you wanted to take this past paranoid speculation, then pin down the variables more.
Even just covering all 4 combinations of Fedora 38 firefox vs Debian 12 firefox-esr and IP addr A vs IP addr B would be a lot more sane line of inquiry here if you want to test this hypothesis for yourself and understand what happened.
And if the notion of ineffable browser fingerprint is scaring you, then consider trying out sites that visualize your browser fingerprint so that you can better understand and reason around what it is actually revealing. Off hand, these two websites are reputable as far as I know, though obviously other sites may do more with fingerprinting than these do:
I was wrong about user agent. Currently in Firefox from Fedora it looks kind of normal, not Qubes OS specific (I probably mixed it with leaking hostname that is the same as VM name in some cases).
Can you simply compare user agent string from the Debian and Fedora templates that you have in those cases? Is it different?
To get your user agent string just look at the top of this page (do not click on links, just on the page): my user agent at DuckDuckGo
I tried that and it was already posted.
Browser is the default from the templates which is Firefox. I dunno if I changed anything browser related in one of the templates but nothing big if any. But they already behave a bit differently which I guess comes from the different default config for the browsers in case of Debian or Fedora. iirc they also have a different user agent which even contains the OS.