Reverse lookup for classless networks

[Grant Taylor]

It has come to my attention that my answer to the following question 
might not have been clear.  So I'll try again.

First I want to be clear that I was discussing what the records should 
be, RFC 2317 Classless IN-ADDR.ARPA Delegation (read: CNAME) or standard 
NS delegation.  I don't care how the records (CNAME or NS) are 
generated.  I care what the records are, CNAME vs NS.

On 12/27/18 11:24 AM, John Levine wrote:
> PS: What's wrong with using $GENERATE in the parent zone like everyone 
> else who uses BIND does?

I have zero problems with actually using $GENERATE in the parent zone 
(or anywhere else).

I do have concerns about using $GENERATE to describe a concept to 
someone who may not be as familiar with DNS, or BIND, much less 
$GENERATE.  As such, I tend to not use $GENERATE when answering questions.

Take the following examples.  Which do you think someone that is new to 
DNS will have an easier time understanding?

--8<--
$GENERATE 1-4 $ CNAME $.bob.example.net.
$GENERATE 5-8 $ NS ns1.example.com.
-->8--

Or

--8<--
1.localhost.  604800  IN  CNAME  1.bob.example.net.
2.localhost.  604800  IN  CNAME  2.bob.example.net.
3.localhost.  604800  IN  CNAME  3.bob.example.net.
4.localhost.  604800  IN  CNAME  4.bob.example.net.
5.localhost.  604800  IN  NS     ns1.example.com.
6.localhost.  604800  IN  NS     ns1.example.com.
7.localhost.  604800  IN  NS     ns1.example.com.
8.localhost.  604800  IN  NS     ns1.example.com.
-->8--

IMHO, the latter is easier to understand.  As a bonus, it conforms to 
standard zone file format.  Something that any DNS administrator should 
be able to recognize and interpret.  I'm unwilling to say the same about 
$GENERATE.

I trust that people that are comfortable with $GENERATE will recognize 
it's use case when they see it.

I learned a long time ago to think about how the person learning 
receives and understands things.  As such, if there is a simple change I 
can do as a teacher to make it easier for them as the student learn, 
then I should do that.



-- 
Grant. . . .
unix || die

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