I've recently built a server using 14.04.1 LTS, I wanted a very quick and simple way for it to let me know if, for example, it needed a system restart after installing upgrades. I decided e-mail was the best option.
I've installed, configured and tested ssmtp to use one of my usual e-mail services.
Also, I've configured unattended-upgrade to e-mail me after any upgrades, at least initially.
Can I get the unattended-upgrade e-mail to come from a specific address? I know I can do that using just mail or ssmtp directly but if I don't specify a "from" address then it defaults to my mail service's default account and I want it to be clear it came from this particular machine. Where can I specify a "from" address for the mail command that unattended-upgrade uses?