Re: ANY queries to tinydns

Hi David,

From what I recall, ANY queries are supposed to return the data that
is in the resolvers cache, otherwise I think you'd be looking at an
AXFR or something of the sort which as I believe most would agree you
wouldn't want to do publicly.

As for DJB I don't know exactly what's going on there, however
according to the RFC's if the size of the packet exceeds 512 bytes and
is in an UDP transaction then it is supposed to set the tc bit in the
packet header. Then the client is supposed to query again via TCP
where EDNS0 can be set to extend the maximum size of the packet
allowing for more data to be transfered.

Not sure if that is really answering your question about DJB however.

-brian



On Wed, Mar 31, 2010 at 12:32 PM, David Hubbard
<[email protected]> wrote:
> Can someone tell me what the official behavior of
> tinydns is supposed to be when an ANY query is
> sent to it?  And preferably when the response
> would be and wouldn't be larger than a udp packet.
> Using wireshark it reports malformed response on
> ANY queries to domains with a lot of records.
>
> I'm trying to troubleshoot an issue with customers
> we provide tinydns-based DNS service for who are
> using Google for email and having delivery issues
> from Yahoo (who appears to run qmail without the
> big-DNS patch).  Google had been serving an ANY
> response that was larger than unpatched qmail would
> tolerate, I posted about it in a google forum and
> they appear to have decreased the records that
> are sent back in an ANY response now, which did
> seem to solve the issues for most of the customers
> who had reported it.  One customer has still had
> the qmail cname error bounce on the Yahoo side so
> they changed their name servers to a BIND-based
> system and the problem went away, changed back to
> our tinydns-based system and problem came back.
> So I'm trying to figure out if we should be doing
> something differently to not have the issue.  We
> do not have axferdns running just FYI.  I also don't
> see why our servers would even be involved as I'd
> expect qmail to query for the ANY record on the
> domain of the MX records, but maybe I'm wrong on
> that.
>
> Thanks,
>
> David
>