Thx
This doesn't really answer the question you asked, but have you considered using a VPN that has a kill switch feature?
My concern is I have to trust the VPN provider...
I used to use Torbirdy in my Whonix-gw Thunderbird a while ago (Installed by default) but it seems it "...is incompatible with Thunderbird 60.6.1...", at least that is the message I get when I look into Tools -> Add-ons in Thunderbird.
I am trying to find the best solution that balances usability with security for my email client in what I assume is the most secure in Qubes (Whonix-gw/Thunderbird).
My understanding is Torbirdy would "Force" Thunderbird thru Tor only.
Good Whonix-Qubes Links:
https://www.qubes-os.org/doc/whonix/
https://www.whonix.org/
Thanks all,