Most authoritative servers, and presumably most operators, associate a single A, AAAA or pair of those two to a single NS RR, but I have seen cases where this is not true.
For instance, representative of the more common configuration, example.org has an NS RR of b.iana-servers.net and that name in turn has one A and one AAAA associated with it. However, imagine b.iana-servers.net actually maps to multiple A RRs. I've seen cases where PTRs can get out of whack. I could imagine server selection or round robin algorithms giving somewhat unpredictable and potentially suboptimal results. Perhaps even some issues with an suboptimal set of additional records being returned. On the other hand... if the NS names are in different zones, perhaps this adds some reliability. I'm curious if anyone is aware of, or can envision, any actual problems or real benefits with this A/AAAA overloading, for a lack of a better term since I'm not sure what to call it. Thanks to my friend Ed Lewis who entertained a version of this question some time back off-list and began his response in his characteristically delightful way with "Problems get solved more easily when it's a genius and an idiot working together". John _______________________________________________ dns-operations mailing list [email protected] https://lists.dns-oarc.net/mailman/listinfo/dns-operations dns-jobs mailing list https://lists.dns-oarc.net/mailman/listinfo/dns-jobs
