Can someone from Amazon please answer.

Josh Reynolds josh at kyneticwifi.com
Fri Aug 26 23:54:32 UTC 2016


Excellent info, thank you Mark.

On Aug 26, 2016 6:53 PM, "Mark Andrews" <marka at isc.org> wrote:

>
> In message <[email protected]
> mail.gmail.com>, Josh Reynolds writes:
> >
> > Just looking at the RFC...
> > -----
> > VERSION Indicates the implementation level of the setter. Full
> conformance
> > with this specification is indicated by version '0'. Requestors are
> > encouraged to set this to the lowest implemented level capable of
> > expressing a transaction, to minimise the responder and network load of
> > discovering the greatest common implementation level between requestor
> and
> > responder. A requestor's version numbering strategy MAY ideally be a
> > run-time configuration option. If a responder does not implement the
> > VERSION level of the request, then it MUST respond with RCODE=BADVERS.
> All
> > responses MUST be limited in format to the VERSION level of the request,
> > but the VERSION of each response SHOULD be the highest implementation
> level
> > of the responder. In this way, a requestor will learn the implementation
> > level of a responder as a side effect of every response, including error
> > responses and including RCODE=BADVERS.
> > -----
> > What am I missing, based on your output?
>
> The servers do not RESPOND to EDNS version != 0 queries.  The following
> sends a EDNS version 1 query and tells dig not to complete the EDNS version
> negotiation so you can see the BADVERS response.
>
> % dig lostoncampus.com.au. @205.251.195.156 +edns=1 +noednsneg soa
>
> ; <<>> DiG 9.11.0rc1 <<>> lostoncampus.com.au. @205.251.195.156 +edns=1
> +noednsneg soa
> ;; global options: +cmd
> ;; connection timed out; no servers could be reached
> %
>
> A EDNS version 0 query to show reachability and that EDNS is supported.
>
> % dig lostoncampus.com.au. @205.251.195.156 +edns=0 +noednsneg soa
>
> ; <<>> DiG 9.11.0rc1 <<>> lostoncampus.com.au. @205.251.195.156 +edns=0
> +noednsneg soa
> ;; global options: +cmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 63224
> ;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 1
> ;; WARNING: recursion requested but not available
>
> ;; OPT PSEUDOSECTION:
> ; EDNS: version: 0, flags:; udp: 4096
> ;; QUESTION SECTION:
> ;lostoncampus.com.au.           IN      SOA
>
> ;; ANSWER SECTION:
> lostoncampus.com.au.    900     IN      SOA     ns-1222.awsdns-24.org.
> awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
>
> ;; AUTHORITY SECTION:
> lostoncampus.com.au.    172800  IN      NS      ns-1222.awsdns-24.org.
> lostoncampus.com.au.    172800  IN      NS      ns-1812.awsdns-34.co.uk.
> lostoncampus.com.au.    172800  IN      NS      ns-78.awsdns-09.com.
> lostoncampus.com.au.    172800  IN      NS      ns-924.awsdns-51.net.
>
> ;; Query time: 126 msec
> ;; SERVER: 205.251.195.156#53(205.251.195.156)
> ;; WHEN: Sat Aug 27 09:40:29 EST 2016
> ;; MSG SIZE  rcvd: 248
>
> %
>
> What you should see is something like the following.  Note the
> version field is zero (0) and the rcode (status) field is BADVERS.
> This response does show a protocol error: AD should not be set in
> this response as there is no authenticated data.
>
> % dig . @a.root-servers.net +edns=1 +noednsneg soa
>
> ; <<>> DiG 9.11.0rc1 <<>> . @a.root-servers.net +edns=1 +noednsneg soa
> ;; global options: +cmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: BADVERS, id: 22570
> ;; flags: qr rd ad; QUERY: 0, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
> ;; WARNING: recursion requested but not available
>
> ;; OPT PSEUDOSECTION:
> ; EDNS: version: 0, flags:; udp: 1232
> ;; Query time: 438 msec
> ;; SERVER: 2001:503:ba3e::2:30#53(2001:503:ba3e::2:30)
> ;; WHEN: Sat Aug 27 09:34:32 EST 2016
> ;; MSG SIZE  rcvd: 23
>
> %
>
> Amazon are not alone here (about 20% of servers fail to respond to
> EDNS version 1 queries) but they are big player so they should be
> doing things correctly.  See
> https://ednscomp.isc.org/compliance/alexa-report.html for others
> serving the Alexa top 1000 that get things wrong there are a lot
> of you out there.  There are also reports for the bottom 1000, .GOV,
> .AU and the root zone at https://ednscomp.isc.org along with a
> online compliance checker so others can test their servers.  You
> just need to name a zone and it will work out the rest or you can
> target individual servers even those not listed in the NS RRset.
>
> There is also a whole series of graphs showing failure trends for
> different EDNS compliance tests at
> https://ednscomp.isc.org/compliance/summary.html
>
> Mark
>
> > On Aug 23, 2016 6:43 PM, "Mark Andrews" <marka at isc.org> wrote:
> >
> > >
> > > I'm curious.  What are you trying to achieve by blocking EDNS version
> > > negotiation?  Is it really too hard to return BADVERS to a EDNS
> > > query with version != 0 along with the version of EDNS you support
> > > in the version field?  Are you deliberately trying to prevent the
> > > IETF from deciding to bump the EDNS version in the future?  Do you
> > > have firewalls that have this behaviour hard coded?  Do you even
> > > test for RFC compliance?
> > >
> > > Mark
> > >
> > > lostoncampus.com.au. @205.251.195.156 (ns-924.awsdns-51.net.): dns=ok
> > > edns=ok edns1=timeout edns at 512=ok ednsopt=ok edns1opt=timeout do=ok
> > > ednsflags=ok optlist=ok,nsid,subnet signed=ok ednstcp=ok
> > > lostoncampus.com.au. @205.251.192.78 (ns-78.awsdns-09.com.): dns=ok
> > > edns=ok edns1=timeout edns at 512=ok ednsopt=ok edns1opt=timeout do=ok
> > > ednsflags=ok optlist=ok,nsid,subnet signed=ok ednstcp=ok
> > > lostoncampus.com.au. @205.251.196.198 (ns-1222.awsdns-24.org.): dns=ok
> > > edns=ok edns1=timeout edns at 512=ok ednsopt=ok edns1opt=timeout do=ok
> > > ednsflags=ok optlist=ok,nsid,subnet signed=ok ednstcp=ok
> > > lostoncampus.com.au. @205.251.199.20 (ns-1812.awsdns-34.co.uk.):
> dns=ok
> > > edns=ok edns1=timeout edns at 512=ok ednsopt=ok edns1opt=timeout do=ok
> > > ednsflags=ok optlist=ok,nsid,subnet signed=ok ednstcp=ok
> > >
> > > --
> > > Mark Andrews, ISC
> > > 1 Seymour St., Dundas Valley, NSW 2117, Australia
> > > PHONE:  +61 2 9871 4742                         INTERNET:
> marka at isc.org
> > >
> >
> --
> Mark Andrews, ISC
> 1 Seymour St., Dundas Valley, NSW 2117, Australia
> PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org
>



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