Re: provisioning software, was DNS RRTYPEs, the difficulty with

Mark Andrews wrote:
> Martin Rex writes:
> > Mark Andrews wrote:
> > > "John Levine" writes:
> > > > In case it wasn't clear, this is an authoritative server.
> > If this is about permitted RCODEs here
> >
> >   http://tools.ietf.org/html/rfc1035#section-4.1.1
> >
> > then an RCODE of 4 in the response looks like a perfectly valid response
> > for a DNS Server to a query, authoritative or not is irrelevant, and
> > if any client chokes on such an answer, it is likely the client that
> > is broken.
> No, its about what should be generated.  NOTIMP != NOERROR no data.
Maybe you believe that NOTIMP should be limited to unsupported OPCODES only?
But that is definitely not what the spec says.

Generating RCODE 4 (NOTIMP) seems _perfectly_ permissible for a DNS server
when responding to a query for an QCLASS or QTYPE that the server
does not implement.

                4               Not Implemented - The name server does
                                not support the requested kind of query.


1034&1035 are both at document maturity level "Full Standard",
1034 says:

  3.7.1. Standard queries


  A standard query specifies a target domain name (QNAME), query type

  (QTYPE), and query class (QCLASS) and asks for RRs which match.  This
  type of query makes up such a vast majority of DNS queries that we use
  the term "query" to mean standard query unless otherwise specified.  The
  QTYPE and QCLASS fields are each 16 bits long, and are a superset of
  defined types and classes.

1035 says:

  RCODE         Response code - this 4 bit field is set as part of
                responses.  The values have the following
                interpretation:

                0               No error condition

                1               Format error - The name server was
                                unable to interpret the query.

                2               Server failure - The name server was
                                unable to process this query due to a
                                problem with the name server.

                3               Name Error - Meaningful only for
                                responses from an authoritative name
                                server, this code signifies that the
                                domain name referenced in the query does
                                not exist.

                4               Not Implemented - The name server does
                                not support the requested kind of query.

                5               Refused - The name server refuses to
                                perform the specified operation for
                                policy reasons.  For example, a name
                                server may not wish to provide the
                                information to the particular requester,
                                or a name server may not wish to perform
                                a particular operation (e.g., zone
                                transfer) for particular data.

                6-15            Reserved for future use.


-Martin
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