Re: RFC 2119 section 6

["D. J. Bernstein" <[e-mail]>]

Kevin Darcy writes:
> it's a perfectly reasonable assumption -- and a perfectly reasonable
> interpretation of the original, unclear specification of AXFR -- that
> the RR's of the zone will be in the Answer Section

I agree. There's no dispute about this. AXFR _servers_ have to put all
the records into the answer section. Any server that violates this rule
will have interoperability problems with some AXFR clients.

Now, given a stream of DNS messages, with empty authority and additional
sections, how does the AXFR _client_ extract all the records?

There are several methods that work. I'm using one. BIND uses another.
The choice of method has no effect on interoperability. axfr-clarify is
violating RFC 2119 section 6 by requiring a particular parsing method.

> If I propose a FOOBAR extension tomorrow, which puts a new type of RR
> in the Additional Sections of, among other responses, AXFR responses,

Then you are an idiot. You are pointlessly breaking compatibility with
working AXFR clients deployed at thousands of sites. Put your protocol
on a new port, and stop demanding that I pay attention to it.

> (let's not split hairs again over
> whether an AXFR client is a DNS client or not)

Zone transfers are requested by name servers. The zone-transfer protocol
is described in RFC 1034 section 4: ``NAME SERVERS.''

Resolution is requested by caches (``resolvers''). The resolution
protocol is described in RFC 1034 section 5: ``RESOLVERS.''

See RFC 1035, page 6, for a data-flow diagram showing the different
roles of caches and name servers.

---Dan


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