authoritative: use other than for zone xfer?
Mark.Andrews at nominum.com
Mark.Andrews at nominum.com
Tue Jun 27 02:49:30 UTC 2000
> Len Conrad wrote:
>
> > Other than enabling/disabling zone transfers, what other
> > advantage/disadvantage is there to an NS being authoritative or not?
> >
> > eg, who/what else cares if an authoritative NS is answering with correct
> > data but non-authoritatively?
Namservers. If aa is not set they will reject answers as being
possibly in error.
>
> Off the top of my head, if a nameserver answers with RCODE=NOERROR and
> ANCOUNT=0, then I believe the querier needs to look at the AA bit to
> distinguish between a referral and "no data of requested type found" from
> an authoritative nameserver. If it's an authoritative answer, the query is
> finished, but if the querier thinks it's an attempted referral, it'll mark
> the server as lame and keep on looking elsewhere for the data. So there's
> at least one case where the AA bit is necessary even for the basic
> query-resolution function of DNS.
No. AA has no effect on whether the answer contain a referral or
not. See RFC 2308 for a fuller description of how to differentiate
the different answers.
Mark
--
Mark Andrews, Nominum Inc.
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: Mark.Andrews at nominum.com
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