nanog mailing list archives

Re: AOL rejecting mail from IP's w/o reverse DNS ?


From: Adam Kujawski <adamkuj () amplex net>
Date: Sat, 6 Dec 2003 21:53:15 -0500


Quoting Adam McKenna <adam () flounder net>:

On Thu, Dec 04, 2003 at 04:59:59PM -0800, Crist Clark wrote:
  $ORIGIN 168.50.204.in-addr.arpa.
  $GENERATE 0-15 $ NS a.ns.$
  $GENERATE 0-15 a.ns.$ A 204.50.168.2

Is any harder than,

  $ORIGIN 168.50.204.in-addr.arpa.
  $GENERATE 0-15 CNAME $.0/28
  0/28              NS      ns.mydomain.org.

That's the whole point.  They are equivalent, but the former doesn't force 
you to invent your own naming scheme or use CNAMES (if using A records in
in-addr.arpa domains is distasteful, then imho using CNAMES is even more
distasteful, not to mention RR's containing the "/" character).

--Adam

Why bother with CNAMES or A records? Is there anything wrong with simply using
NS records for each adress? i.e.:

$ORIGIN 109.246.64.in-addr.arpa.
1        NS         ns1.customerA.com.
1        NS         ns2.customerA.com.
2        NS         ns1.customerA.com.
2        NS         ns2.customerA.com.
...
16       NS         ns1.customerB.com.
16       NS         ns2.customerB.com.
17       NS         ns1.customerB.com.
17       NS         ns2.customerB.com.

If the customer has a dozen name servers they want you to allocate reverse DNS
for, it could become unwieldy, but technically, is there anything wrong with
this setup?

-Adam



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