Multiple SOA records?
Kevin Darcy
kcd at chrysler.com
Wed May 7 22:32:33 UTC 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
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