help me explain

Simon Hobson dhcp1 at
Fri Oct 21 19:54:09 UTC 2016

"Cuttler, Brian R (HEALTH)" <brian.cuttler at> wrote:

> I just need one for the, nuke all of the cms<vlannumber> ones.

Yes, but see below ...

> What about the ones I'd created for the Reverse zones, are those needed at all?

That depends on your setup.

If your internal DNS is setup with the correct SOA records, AND you aren't using signed updates, then you don't need any zone declarations at all. By default, the server will look at the SOA record for the zone ( or in your case) and get the master DNS server from that - then sends the (unsigned) update requests to it.
This does require that the DNS server be setup to accept unsigned updates, which in the general case is "unsafe". You could lock it down and just accept updates from certain IP addresses - eg if this is a dedicated system, with restricted users (so you can trust anyone with access), then just accepting updates from "localhost" may be OK.

But in the general case, you want to restrict the system to signed updates. To do this, you need to define each zone in the DHCP server just so you can specify the key to be used for each one.

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