[dns-operations] EDNS0 client-subnet option from Google Resolvers

[Mark Andrews]

In message <5629DF54.5040500 at switch.ch>, Daniel Stirnimann writes:
> > Is this
> > because the resolver figured out that our authoritative name server is
> > not responding this option, so they don't send it every time but just
> > from time to time to check if we support it now?
> 
> Looks like these are indeed probing requests. Found the following:
> 
> "This is implemented by probing nameservers at a low rate with ECS
> queries and caching the ECS capability for each nameserver. Therefore if
> your nameservers do not support ECS, they may still receive a few ECS
> queries occasionally. And if your nameservers just started to support
> ECS, it may take us several hours to detect the change and start to send
> ECS queries to them."
> 
> https://groups.google.com/forum/?hl=en#!topic/public-dns-announce/67oxFjSLeUM
> 
> Daniel
> -- 
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> Daniel Stirnimann, SWITCH-CERT
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I hope they also graph the support level along with the error levels
they see.  It would be interesting to see how they compare to the
unknown option datasets at https://ednscomp.isc.org/compliance/summary.html

Mark
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org