Active directory has each domain controller updating its own SRV record on the same <qname,qtype,qclass> tuple. These updates happen at different times and need to expire if a domain controller becomes unreachable.
A different case is when you have multiple prefixes from different providers with different lifetimes. You then end up with multiple AAAA records that need to expire at different times. Mark > On 28 Aug 2018, at 8:34 am, Ted Lemon <mel...@fugue.com> wrote: > > Sorry, I realized that I accidentally hit "reply" instead of "reply all." > > The issue that I raised with Tom is that for the DNSSD SRP use case, the only > names that receive updates from multiple services are service names (IOW, not > service instance names). In the case of SRP, PTR RRs in service names > always point to service instance names, which are per-service, and hence can > be counted on to expire on a single schedule. So for the use case of SRP, > the easiest way to handle deleting service name PTR RRs is to take advantage > of the semantics of DNSSD: when a service instance SRV record expires, also > delete the PTR RR on the service name that points to it. > > The reason I bring this up is that it's the most complicated use case I know > of. Is there some other use case where we expect more than one DNS Update > client to be updating RRs of the same type on the same name? How would this > even work without SRP semantics? If this is not expected, then any > complexity in the timeout RR that's present only to support that use case is > unnecessary. > > This is what has been motivating my questions about use cases. I'm sorry I > didn't make that clear earlier. -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
