In https://www.postfix.org/transport.5.html I don't see the syntax @domain. Just domain. What is going on?
The priority setting is there for a reason: most packages get downloaded from the LAN when we install here.
This stays in the final environment and pollutes it.
The issue with auto-reboot here is you need to monitor the installation and then select memtest86 after it has finished.
Are the last two lines necessary, considering the first line?
I have not looked into it, but considering your sloppy code above, I recommend you review this and double check that this is the right way of doing it.
https://github.com/NixOS/nixpkgs/blob/nixos-24.05/nixos/modules/services/mail/postfix.nix#L752-L755
Does this not work for some reason, or is it your usual sloppiness?
Is this really required? I would expect NixOS to deal by itself with services.postfix.mapFiles without requiring any additional user-defined systemd services.
Still zero explanation why this would be required for your tunnel only and not altnet, nor why it works without it anyway.
That doesn't make a lot of sense, please check with Greg.