Re: DNS & IPv6

From: Henrik Nordström <henrik_at_henriknordstrom.net>
Date: Mon, 24 May 2010 00:21:29 +0200

sön 2010-05-23 klockan 15:23 +0200 skrev Kinkie:
> >> Do the two lookups by some reason need to be in separate queries?
> >> Can't we just ask for the A and AAAA in the same query packet?
> >> Sorry for my ignorance..
> >
> > I wonder how many resolvers will actually handle both queries in the
> > same request...
>
> No idea. I guess it depends on how magic AAAA is..

Ran a quick test and it seems that bind rejects requests with more than
one query with RCODE 1 "Format error".

A little digging finds this bind code:

5223 /*
5224 * Check for multiple question queries, since edns1 is dead.
5225 */
5226 if (message->counts[DNS_SECTION_QUESTION] > 1) {
5227 query_error(client, DNS_R_FORMERR, __LINE__);
5228 return;
5229 }

Not entirely sure this is intentional, but at least effectively stops
any attempts at using DNS requests with multiple queries.

Regards
Henrik
Received on Mon May 24 2010 - 06:46:36 MDT

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