authoritative: use other than for zone xfer?

[Barry Margolin]

In article <200006272353.JAA08746 at bsdi.dv.isc.org>,
 <Mark.Andrews at nominum.com> wrote:
>
>> In article <200006270249.MAA05917 at bsdi.dv.isc.org>,
>>  <Mark.Andrews at nominum.com> wrote:
>> >
>> >> 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.
>> 
>> Do they really reject non-authoritative answers?
>
>	Yes.  See src/bin/named/ns_resp.c, search for "Lame server".
>	The fact that the server is lame is cached for 10 minutes
>	(default).

I searched for that, and the comments above it indicate that "Lame server"
warnings are only generated when the server returns a referral to the same
or higher level.  I'm a bit confused by that, because I thought that was
what caused "bad referral" errors.  I searched for that, but had trouble
backtracking to figure out the specific logic that resulted in this
message; the best I can make out is that they both occur when the response
contains delegations to the same or higher level, and "Lame server" occurs
when this is non-authoritative, while "bad delegation" occurs when it's
authoritative.

I looked through ns_resp.c for all the uses of hp->aa and it didn't seem
like any of them caused the answer to be ignored, but I admit that I can't
always figure out named code very well (I'm usually pretty good at figuring
out program logic, but named is pretty complex).  ns_resp.c is especially
confusing because some parts of it are looking at the fields in the
response to a recursive query that it sent out, while others are looking at
the fields in a response that it's about to send to the client.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Burlington, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
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