Delegation of CIDR Block

[Bob Vance]

I'm not sure what you're asking.

Please bear in mind that I am far from an expert on DNS, but I do
know a few things :)


>It is not based on RFCs or clear references to any DNS book but on
>limited experience.

Actually, it is discussed in "DNS an BIND", I believe.
Also, RFC2137 defines it.

My $.02 :
However, it seems that it *was* just a happy happenstance that this
technique was available and took a stroke of genius to discover it -- it
was not part of the original thought processes of DNS, which was created
and defined long before CIDR came into vogue.

>Often the hierarchical breakdown for reverse zones is aligned on
>class-C sub-net address boundaries, i.e. reverse is done in chunks of
>256.

That's the way it was done, originally.  Then came CIDR.


>This ISP seems reluctant to break down the reverse zone into small
>chunks.

That does seem to be true :|


However, as I pointed out, all it takes is a few $GENERATE statements
-- and reliance on the customer to do the thing right, as Andras
pointed out :)

Actually delegating new sub-zones of the "standard" reverse zone and
pointing the CNAMEs into those is a little more work, and for partial
Class C's, I can't really see the advantage of doing it that way.
It means more NS records and more zones.


-------------------------------------------------
Tks        | <mailto:BVance at sbm.com>
BV         | <mailto:BobVance at alumni.caltech.edu>
Sr. Technical Consultant,  SBM, A Gates/Arrow Co.
Vox 770-623-3430           11455 Lakefield Dr.
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=================================================





-----Original Message-----
From: Claude Marinier [mailto:claude.marinier at dreo.dnd.ca]
Sent: Tuesday, February 13, 2001 10:35 AM
To: Bob Vance
Subject: RE: Delegation of CIDR Block


My understanding of the issue may not be accurate. It is not based on
RFCs
or clear references to any DNS book but on limited experience. Please
correct me if I am wrong.

Often the hierarchical breakdown for reverse zones is aligned on class-C
sub-net address boundaries, i.e. reverse is done in chunks of 256. This
often does not match the breakdown of domains.

This ISP seems reluctant to break down the reverse zone into small
chunks.

Is this practice common?

On Tue, 13 Feb 2001, Bob Vance wrote:
> Of course, in this case the ISP is *already* letting him master the
> forward domain, but just doesn't want to let him do a partial reverse.

--
Claude Marinier, Information Technology Group
claude.marinier at dreo.dnd.ca
Defence Research Establishment Ottawa (DREO)    (613) 998-4901  FAX
998-2675
3701 Carling Avenue, Ottawa, Ontario  K1A 0Z4
http://www.dreo.dnd.ca