Re: [dns-privacy] draft-ietf-dprive-dnsodtls-01

In message <20150723153608.8F85733A8962@rock.dv.isc.org>, Mark Andrews writes:
> 
> This is wrong.  DNS servers should respond with NOTIMP or FORMERR.
> The actual rcode is implementation dependent.  This is not to say
> all will respond.  Just don't expect silence.
> 
>    DNSoD can run over standard UDP port 53 as defined in [RFC1035].  A
>    DNS client or server that does not implement this specification will
>    not respond to the incoming DTLS packets because they don't parse as
>    DNS packets (the DNS Opcode would be 15, which is undefined).

More correctly they don't respond because they are marked as "query
reponses" (qr=1) and there is little point telling a responder they
gave a bad response.  Opcode 15 and malformed packets are not the
reason for the lack of response.

> e.g.
> 
> ; <<>> DiG 9.11.0pre-alpha <<>> +opcode=15 +noedns +header-only +qr +noad
> ;; global options: +cmd
> ;; Sending:
> ;; ->>HEADER<<- opcode: RESERVED15, status: NOERROR, id: 25683
> ;; flags: rd; QUERY: 0, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
> 
> ;; QUESTION SECTION:
> 
> ;; QUERY SIZE: 12
> 
> ;; Got answer:
> ;; ->>HEADER<<- opcode: RESERVED15, status: NOTIMP, id: 25683
> ;; flags: qr rd; QUERY: 0, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
> ;; WARNING: recursion requested but not available
> 
> ;; Query time: 0 msec
> ;; SERVER: 127.0.0.1#53(127.0.0.1)
> ;; WHEN: Fri Jul 24 01:29:00 EST 2015
> 
> -- 
> Mark Andrews, ISC
> 1 Seymour St., Dundas Valley, NSW 2117, Australia
> PHONE:	+61 2 9871 4742		         INTERNET: marka@isc.org
> 
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-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka@isc.org