DNS reverse sub delegation NXDOMAIN problem, Class C

/dev/rob0 rob0 at gmx.co.uk
Tue Aug 19 23:21:44 UTC 2014

Sorry, this is going to be a pedantic post, so I might as well start 

> Subject: Re: DNS reverse sub delegation NXDOMAIN problem, Class C

No, there's no such thing as "Class C", so please forget that.  It's 
a /24 network.  CIDR is in; class is dismissed.

On Tue, Aug 19, 2014 at 07:03:20PM +0200, Matus UHLAR - fantomas wrote:
> On 19.08.14 11:54, Bazy V wrote:
> >One post said 220/24 is not the correct format,
> >Another post said that is the format.
> no post said this.

Right.  I wonder where the OP got that idea?

> >Not sure which one is correct.
> 220.20.172.IN-ADDR.ARPA is the correct zone into which to put PTR 
> records.
> >Setting 220            NS            ns2.sub.test.com.

Test.com is a real Internet domain.  Please don't use that if you 
aren't the actual owner.

> this belongs to the 20.172.IN-ADDR.ARPA domain

Yes, to repeat, and enhanced for RFC 2606 compliance:

220		NS	ns2.sub.example.com.

> on your recursive nameserver
> - the one your resolv.conf points to.

Well no, not necessarily.  This is authoritative service we are 
discussing here.

That said, sure, typically you're going to host such internal-only 
zones on a server that also does recursion.  That's not required, 
however.  The recursive server could have stub or static-stub zones, 
or even an alternate root zone, which points to the authoritative 

Pedantry complete.
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