Topic of #IETF conversation in #HAPPYWG and elsewhere is when and for how long it is acceptable to ignore #DNS TTLs (as long as the client validates the server cert still matches): https://datatracker.ietf.org/doc/html/draft-gakiwate-dnsop-optimistic-dns-00 It is already generating many good hallway conversations. The tension is between performance ("if we ignore TTLs and use minutes/hours/days old A/AAAA records things connection establishment is faster") and operational correctness and safety. Clients have been implementing this for years, but more want to do so. Operationally this has the potential to be quite surprising, making it much harder for operators to drain traffic from servers by taking them out of the DNS, whether to reuse IPs for other purposes, for maintenance, for DNS load balancing, or when switching providers. As much as we might like it to, just because a server returns a valid cert is not an reason to assume that it is intended to be in service. (Not that naming or cache invalidation are hard problems in Computer Science or anything.)