On Thu, 2 Jul 2020, Paul Vixie wrote:
until someone invents faster than light travel, round trips and remote state will be the second and third most expensive things on the internet. (the most expensive thing is complexity.) i think we can usefully discuss whether to set TC=1 if the only thing that won't fit is glue, but some glue did fit. but our goal should be to allow smart initiators to avoid retrying with TCP out of reflex. my recommendation of TC=0 is to suppress reflexive TCP retries.
I wouldn't disagree but it seems to me once again it's a tradeoff between performance and correctness. I'd prefer correctness, particularly since it seems that the option to use what's in a truncated referral gets you both.
3. even without TC=1 you will know there's under-zonecut glue you didn't receive, because you saw the NS RR, and the only path to the address RR is through that NS RRset.
Well, maybe. Even if you got one A record there might be others. Or if you got an AAAA record but no A record and you're on an IPv4 network, you can't tell whether there's a lurking A record or not, or vice-versa. (See the glue for j.zdnscloud.com in the root.)
If we do it your way, if any NS is in-zone and the lookups fail, you *always* need to do a TCP query just to see if if the UDP response left something out.
R's, John PS: I'm less worried about round-robin DNS, since then it's clearly a deliberate decision by the parent to leave some of the answers out. _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
