Re: axfr-clarify's fraudulent claims of consensus

["D. J. Bernstein" <djb@cr.yp.to>]

Josh Littlefield writes:
> RFC1034 clearly states that the answer section "carries RRs which
> directly answer the query."  I don't see how anyone could conclude
> that AXFR clients should look for zone RRs anywhere else.

There is overwhelming consensus that (in the absence of extended
behavior requested by the client) the AXFR _server_ must leave the
additional section and authority section empty. It must put the data
into the answer section. All existing servers work this way---and must
do so for interoperability.

There are several perfectly valid parsing strategies for the client.
In particular, my software uses the simple strategy

   while there are records left
      read a record

while BIND 9 uses the slightly more complicated strategy

   while there are records left in the answer section
      read a record

Both strategies work, since servers put all records into the answer
section. Neither strategy creates any interoperability problems.

There is certainly _not_ consensus on telling the _client_ to use the
BIND 9 strategy. Furthermore, any such statement (whether ``MUST'' or
``SHOULD'') would blatantly violate RFC 2119, section 6.

This is about the tenth time that I have had to point out the blazingly
obvious fact that constraining _server_ behavior is not the same as
constraining _client_ behavior.

---D. J. Bernstein, Associate Professor, Department of Mathematics,
Statistics, and Computer Science, University of Illinois at Chicago