[DNSOP] Can an RRSET remain valid past the expiration timestamp on its signing RRSIG?

Nick Johnson <nick@ethereum.org> Wed, 24 July 2019 05:50 UTC

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From: Nick Johnson <nick@ethereum.org>
Date: Wed, 24 Jul 2019 17:50:04 +1200
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To: dnsop WG <dnsop@ietf.org>
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Subject: [DNSOP] Can an RRSET remain valid past the expiration timestamp on its signing RRSIG?
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Suppose I receive a response containing an RRSET with records with
ttl=3600, signed with an RRSIG that has an expiration timestamp 60 seconds
from now.

After validating the signature, can I cache the RRSET for 3600 seconds, or
only for 60 seconds? If the former, and the RRSET is a DNSKEY, can I rely
on it to validate other RRSIGs for the entire 3600 seconds?

-Nick Johnson