*smtp1.pyrocufflink.blue* is a VM that will replace
*smtp0.pyrocufflink.blue*, a Raspberry Pi.
I decided that there is little use in having the availability guarantee of
a discreet machine for the SMTP relay. The only system that would NEED
to send mail if the VM host fails is Zabbix, which operates as its own
relay anyway. As such, the main relay can be a VM, and the Raspberry Pi
can be repurposed as a recursive DNS server.
Dustin