> I haven't seen any measurement studies. But at a recent DNS-OARC > meeting, Bert Hubert mentioned that PowerDNS were driven > to implement this based on a real operational problem: too many > NXDOMAIN eliciting queries from one of their large resolvers to the > F.ROOT server resulting in them being response rate limited.
And the clue-by-four hits me in the face. Ouch. Yes, right, we are not doing an extra cache lookup to look for the parent NXDOMAIN because we are already doing a cache search on that name to figure out who's authoritative for it. So indeed, as you and John and possibly Paul said, the performance hit for doing that part of the search isn't an issue. So then the main issue that I have is the normative requirement to not answer out of the cache when I have a valid cache entry for a name that happens to have a cached NXDOMAIN above it in the hierarchy. If I don't have to do that, then there's no performance issue; if I do have to do that, then my objection still applies. There's no benefit to the root servers in this normative requirement, because these queries are being answered out of the cache. _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
