Re: [DNSOP] Review of draft-ietf-dnsop-serve-stale-02.txt

Tony Finch <dot@dotat.at> Mon, 05 November 2018 18:45 UTC

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Date: Mon, 5 Nov 2018 18:45:25 +0000
From: Tony Finch <dot@dotat.at>
To: Dave Lawrence <tale@dd.org>
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Subject: Re: [DNSOP] Review of draft-ietf-dnsop-serve-stale-02.txt
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A few notes following the presentation and discussion earlier today
(unrelated to Mukund's comments - I'm just stealing a suitable thread)

Re. the EDNS options, if you go for a 1 bit version it should apply only
to the answer section. The only time this will be ambiguous is when there
are CNAME/DNAME chains present.

I was rather disconcerted by the 1 week default serve-stale limit in
BIND's implementation. It seems to me that the value should be tuned to
match typical outage lengths. A day seems to me to be much more reasonable
than a week, though for my servers I have chosen an hour.

Part of the reason I like serve-stale is that I think it will make outages
easier to triage for my IT support colleagues. Network connectivity
problems often look like DNS problems to even fairly knowledgable people.
If the DNS continues to provide answers when the network is a bit broken
then the investigation is more likely to head in the right direction
sooner. (My logic for choosing an hour is that if things are broken for
longer than that then it clearly isn't my fault any more!)

Tony.
-- 
f.anthony.n.finch  <dot@dotat.at>;  http://dotat.at/
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