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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