To avoid having a single point of failure, a second recursive DNS server
is necessary. This will be useful in cases where the VM hosts must both
be taken offline, but Internet access is still required.
The new server, *dns1.pyrocufflink.blue*, has all the same zones defined
as the original. It forwards the *pyrocufflink.blue* zone and
corresponding reverse zones to the domain controllers, and acts as a
slave for the *pyrocufflink.red* zone.
