multiple PTR RRs [dnsviz]

[Joseph S D Yao]

On Wed, Jun 02, 2010 at 03:40:31PM +0000, Paul Vixie wrote:
> Chris Thompson <cet1 at cam.ac.uk> writes:
> 
> > Nothing that I can see. Maybe dnsviz can't cope with multiple PTR
> > records in an RRset, as your first case has? (On the other hand it
> > handles multiple A records in forward zones OK.)
> 
> to be fair, multiple PTR RRs is something we added in BIND gethostbyaddr()
> in more or less direct contravention to RFC 1034. if dnsviz doesn't handle
> it (and i don't know if it doesn't) then it's not dnsviz's fault at all
> since the DNS RFC's say that there will only be one PTR RR at an in-addr.


Vixie, not to presume to argue with you about what Paul M meant by that,
but in RFC 2181 Elz and Bush say:

10.2. PTR records

   Confusion about canonical names has lead to a belief that a PTR
   record should have exactly one RR in its RRSet.  This is incorrect,
   the relevant section of RFC1034 (section 3.6.2) indicates that the
   value of a PTR record should be a canonical name.  That is, it should
   not be an alias.  There is no implication in that section that only
   one PTR record is permitted for a name.  No such restriction should
   be inferred.

That having been said, I always feel better, myself, when there is a
1-to-1 mapping.


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** Joe Yao				jsdy at tux.org - Joseph S. D. Yao
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