Joe Abley wrote on 2022-11-07 13:38:
... I continue to think the necessary/useful debate is a silly one. In the context of a referral response, glue means additional-section records that the sender of the referral imagines might possibly be helpful to the receiver (which in turn means it might be helpful to the sender, since the sender is in the business of sending things that can be used). The sender has no way of knowing for sure whether that will turn out to be true at the time when the response is sent.
back before the dawn of time, akira kato and i tried to reason about these distinctions, so that additional data rrsets could be prioritized according to utility, and "unnecessary" truncation could be avoided. this was specifically in the context of referral responses, since other uses of additional data (like MX or SRV) were always for convenience.
below-delegation had a higher priority than in-bailiwick which had a higher priority than out-of-bailiwick. i still think this is so.
the sibling case is either degenerate (mutual dependency) which should just fail, or normal in which case you'll get the additional data you need when you try to chase the out-of-bailiwick NS.NSDNAME.
i think codifying this terminology apart from the question of referral response priorities was always a stretch and need not be pursued.
-- P Vixie _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
