RCODE: Not Implemented

[Jim Reid]

>>>>> "Mark" == Mark  <msanp at earthlink.net> writes:

    Mark> When querying my name servers for a resource record type
    Mark> that I am sure they don't implement ( SRV, SIG ) named
    Mark> ummmm........ works.  That is it tells me that there aren't
    Mark> any such records.

Er, the output from dig showed that. The answer section of the reply
was empty. 

    Mark> I thought that named would respond with
    Mark> the RCODE in the response packet set to "NOT IMPLEMENTED" at
    Mark> least for the older name servers.  I get this behavior from
    Mark> BIND 4.9.7, 8.1.2 & 8.2.2 name servers.

Are you sure about that? Are these servers returning NOTIMP if you ask
them for a SIG record? I would expect them to either return NXDOMAIN
or NOERROR with an empty answer section. NOTIMP should be returned
when the name server doesn't implement the opcode on the lookup. The
opcode would denote things like QUERTY, UPDATE, NOTIFY, IQUERY and
stuff like that, not the record type for the name that's been looked
up. The record type is specified in the query's QTYPE field.

    Mark> I notice that nslookup won't even let you
    Mark> send such a query if it doesn't recognize the RR type.

All the more reason to put a bullet in nslookup...

    Mark> when does named reply with "NOT IMPLEMENTED"??

See above. Or lines 279-312 of ns_req.c in BIND8.

    Mark> $ dig SIG cookie.com

    Mark> ; <<>> DiG 8.1 <<>> SIG cookie.com
    MarK> ; (1 server found) 
    Mark> ;; res options: init recurs defnam dnsrch 
    Mark> ;; got answer:
    Mark> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 10
				  ^ dig set the opcode to QUERY
				    (surprise, surprise!)
    Mark> ;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 2
					     ^ Look ma! No answers!
		    
    Mark> ;; QUERY SECTION:
    Mark  ;; cookie.com, type = SIG, class = IN

Notice there's no ANSWER SECTION.....

    Mark> ;; AUTHORITY SECTION:
    Mark> cookie.com.  2D IN NS INTERPAGE.NET.
    Mark> cookie.com.  2D IN NS ADMIRAL.INTERPAGE.NET.  

    Mark> ;; ADDITIONAL SECTION:
    Mark> ADMIRAL.INTERPAGE.NET.  2D IN A 204.75.164.2 
    Mark> INTERPAGE.NET.          2D IN A 204.75.164.1