> On 6 Aug 2020, at 02:05, Pieter Lexis <pieter.le...@powerdns.com> wrote: > > Hi folks, > > Section 2.4.1 says > > ``` > The primary purpose of AliasMode is to allow aliasing at the zone apex, > where CNAME is not allowed. In AliasMode, TargetName MUST be the name of > a domain that has SVCB, AAAA, or A records. > ``` > > and section 4.1 says > > ``` > When replying to a SVCB query, authoritative DNS servers SHOULD return > A, AAAA, and SVCB records in the Additional Section for any in-bailiwick > TargetNames. > ``` > > Does this mean that the processing differs from 'regular' in-zone CNAME > processing? Where I define this processing as "look for the Target name > with the type from the query and use that result's status as query result". > > Considering this zone (abbreviated): > > ``` > svcb-alias.example.net SVCB 0 alias-target.example.net > alias-target.example.net A 192.0.2.1 > ``` > > What would be the correct response to a svcb-alias.example.net|SVCB query? > > ``` > ;; QUESTION SECTION: > ;svcb-alias.example.net. IN SVBC > > ;; ANSWER SECTION: > svcb-alias.example.net. 3600 IN SVBC 3600 0 > alias-target.example.net > example.net. IN SOA 3600 [....] > > ;; ADDITIONAL SECTION: > alias-target.example.net. 3600 IN A 192.0.2.1 > > ``` > > or > > > ``` > ;; QUESTION SECTION: > ;svcb-alias.example.net. IN SVBC > > ;; ANSWER SECTION: > svcb-alias.example.net. 3600 IN SVBC 3600 0 > alias-target.example.net > > ;; ADDITIONAL SECTION: > alias-target.example.net. 3600 IN A 192.0.2.1 > > ```
The second. > With the former, implementers would be be able to reuse the existing > aliasing code paths. With the latter, changes will have to be made to > the codepath as the AliasMode is not a 'true' alias as CNAME is. It isn’t an ALIAS. Its a bad description that is the result of HTTP mis-using the CNAME record for the last 20 odd years. HTTP has always needed a "server for" record like MX or SRV. We just haven’t been able to get http developers invested in the idea until now. > In the same vein, what happens in a zone like this (with the same > incoming query for svcb-alias.example.net|SVCB): > > ``` > svcb-alias.example.net SVCB 0 alias-target1.example.net > alias-target1.example.net SVCB 0 alias-target2.example.net > alias-target2.example.net SVCB 1 . ipv4hint=192.0.2.1 > > alias-target2.example.net A 192.0.2.1 > ``` > > Do *both* alias-target{1,2}.example.net|SVBC records end up in the > ADDITIONAL section. Or are they (as is the case with an in-zone CNAME) > considered an answer and should they go into the ANSWER section? They go in the additional section. > I find the alias mode semantics (on the DNS-level) unclear and > under-specified in the draft. I look forward to guidance from the authors. > > Best regards, > > Pieter > > -- > Pieter Lexis > PowerDNS.COM BV -- https://www.powerdns.com > > _______________________________________________ > DNSOP mailing list > DNSOP@ietf.org > https://www.ietf.org/mailman/listinfo/dnsop -- 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