Evolution. It works with MS Exchange.
I have an elderly and rather unloved Gmail account for testing and spam reception only and a couple of Yubi keys so I'll see what I can do with them. I probably ought to use the Gmail account more but I'm concerned that Google will kill it off 8) I got it when the G stood for gigabyte because everyone else set quotas in the 10s or low 100s of megabytes. "Do no evil" Google were as cool as fuck but that was a long time ago. Sad really.
It's always DNS (unless it's NTP).
So now should we add dd to DNS and NTP? No. dd an image over something you shouldn't is simply a daft thing to do and I'm sure many here use dd instead of a GUI or something more friendly that stops you from doing the daft thing. However, forgetting to consider DNS and NTP is when you cease to be a technician. DNS and NTP failure cause way more problems than they should at a casual glance.
When I was a lad people used to riff on # rm -r ./ * destroying systems (lol). Bear in mind that . means current directory and .. means parent directory and that all directories apart from / have both . and .. entries. So rm -r should walk both upwards and then downwards. Even better, because Unix type systems can do this sort of thing, deleting the rm binary itself won't stop the destruction. I'm not sure when the box would eventually panic, if at all. I think I'll clone a VM and find out.
rm these days won't do that. It even has a --no-preserve-root option ...