Re: Multiple SOA records?

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Multiple SOA records?
\ Lars Hecking (6 May 2008)
. \ Kevin Darcy (6 May 2008)
. . \ Lars Hecking (6 May 2008)
. . . \ Kevin Darcy (6 May 2008)
. . . . \ Lars Hecking (7 May 2008)
. . \ Lars Hecking (7 May 2008)
. . . \ Chris Buxton (7 May 2008)
. . . \ Kevin Darcy (7 May 2008)
. \ Chris Thompson (7 May 2008)

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Subject:	Re: Multiple SOA records?
Group:	Bind-users
From:	Kevin Darcy
Date:	7 May 2008

Lars Hecking wrote:
> Kevin Darcy writes:
> [...]
>
>> traininghott.com definitely seems to have a standards-conformance issue
>> in the way it handles SOA queries
>>
> [...]
>
> Hhm, I think I would disagree here. After all, their name servers do return
> SOA records when queried directly, even if they are too many.
>
Semantics. There can only be one SOA RR in a given zone. SOA RRs must
have an owner name which is identical to the zone name. Put those two
things together, and you get that a given name can only own at most one
SOA RR. Expressed another way, SOA is a "singleton type".

Are you with me so far?

These servers are responding, to a regular query (as opposed to a
zone-transfer request) with two SOA RRs that have the same owner name
but different RDATA. How can this possibly conform to standards? One of
those RRs -- take your pick -- can't be legally owned by its owner name,
because of the existence of the other RR. One of them conforms to
standards; the other one violates them.

- Kevin