On Sun, Jun 28, 2009 at 8:15 PM, Edgar Lovecraft<exim-list@???> wrote:
> On Sun, 28 Jun 2009 12:23:38 -0400 Aaron Wolfe <aawolfe@???> wrote:
>>
> ..<snip snip>...
>>
>> Last I checked into this issue, the RFCs do not explicitly allow or
>> disallow multiple PTRs. This translated to inconsistent behavior in
>> the real world as some resolvers can understand them and some can't.
>> Unless things have changed, I don't think quite legal or less common is
>> really the correct term for this, more like good luck and say a prayer.
>> But maybe something new has happened?
>>
>>
>
> Actualy, the RFCs are very clear that multiple PTR records are allowed for
> single IP addresses.
>
> Refernces:
> RFC 2181 Section 10.2
>
> RFC 1034 Section 5.2.1 sub-section 2
> "A type PTR query is used to get the RR with the primary name of
> the host. For example, a request for the host name
> corresponding to IP address 1.2.3.4 looks for PTR RRs for
> domain name "4.3.2.1.IN-ADDR.ARPA"."
>
> Please take note of the "looks for the PTR RRs", 'resouce records', not
> just 'resource record'.
>
Yes, I remember this and this is the part that isnt clear, isn't it?
Not trying to restart any kind of debate, but doesn't this reference
also mention "the RR" with "the primary name", both singular? English
can be unclear. Consider the phrase, "I'm driving down the street
looking for houses with the address 123", which maybe isn't a great
example but hey i'm not a cunning linguist.
Regardless, the important thing, and what I was interested in most was
whether the behavior was now more consistent. This is what matters
if you're going to use them. Can we trust that multiple PTRs will
mostly work on most platforms now? As in the resolvers will return
multiple results, and most software will sift through many results
instead of just taking the first one? This did not seem to be the case
a couple years ago.
-Aaron
>
> ..<snip snip>...
>>
>
>
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