alt Hacker NewsCAA records are only checked by the CA at the point of issuance, not by the client later. If they did, there are problems to consider:
1. A domain would have to keep the CAA records for a CA in place to keep using the certificates from that CA, but that means continuing to authorise new issuance too. Right now, I can remove the `letsencrypt.org` value to stop them from issuing new certificates for me, but I can keep using any certificates I have until they expire.
2. The client would need to have support for this new DNS RR type.
3. The client would need a secure way to query DNS, which is not widespread.
1. Yeah, that's true. It'd need to be something akin to SPF where it gets validated and kept up to date. 2. Yep, you're right. CAA isn't the correct record type. 3. I'd guess that in the vast majority of cases where a TLS cert is used, DNS is also in use. In the case of an offline validation, you're also not able to check CRL, OCSP, etc. so there are already tradeoffs there. Oh, wrt to "secure" - I guess that's the gotcha. DoH would be chicken-and-egg... something like DNSSEC would be needed, though that may be an impossible prerequisite.