On Wed, Mar 29, 2017 at 11:14 AM, Pieter Lexis <pieter.le...@powerdns.com> wrote: > Hello Anthony, > > On Wed, 29 Mar 2017 08:51:50 -0500 > Anthony Eden <anthony.e...@dnsimple.com> wrote: > >> https://datatracker.ietf.org/doc/draft-dnsop-eden-alias-rr-type/ >> >> This draft describes the ALIAS/ANAME record (aka CNAME-flattening) >> that numerous vendors and DNS providers are now supporting in >> proprietary fashions. I hope that this draft will eventually lead to a >> good mechanism for interop of ALIAS/ANAME records. > > First off, thank you for this. I would love to hear from current implementors > of ALIAS/ANAME/CNAME-flattening what their ideas/critisisms are. > > This said, I have several comments after a first quick read of the document. > > There is no mention of the fact that ALIAS is mostly meant for zone apexes > where other records MUST be present and a CNAME cannot exist. CNAMEs would > cover non-apex usecases for ALIAS.
As Tony pointed out, there are use cases for non-apex nodes as well. > > I miss guidance what should happen when an ALIAS record is queried directly > (would it be returned, should it be refused, should it be an empty response?). It's a good point. Our implementation doesn't expose the ALIAS itself as a queryable type, but there is a legitimate argument to allow it. > > I miss words on the interaction between ALIAS records and other (mostly A and > AAAA) records on the same node. +1. In our case we would return both the static records as well as the materialized records. > > Section 3.1 > > "The server will respond with one or more A records", I fail to see why this > cannot be zero or more. Am ALIAS target without A or AAAA records should > yield an empty response from the authoritative server. Good point. > > "If the recursive query returns an NXDOMAIN response, then the authoritative > name server MUST return an NXDOMAIN response as well.". If any other records > exist (which is always the case for the apex), or if there are labels > underneath the ALIAS'es name, the authoritative server cannot send out > NXDOMAIN. Also a good point. I actually need to check our implementation to see how it behaves now in this case. > > Section 3.3 > > This section has 2 similar paragraphs, one with should and the other with > MUST. Yes, I am removing the extra paragraph and going with MUST. > > Asking directly for a CNAME for a node that only has an ALIAS record should > yield a response indicating that RRType does not exist at that node. I agree. > > Again, thank you for starting this draft. I support adoption of this draft in > the dnsop WG to facilitate better interop between > ALIAS/ANAME/CNAME-flattening implementors. Thank you for your feedback, I appreciate it. -Anthony -- DNSimple.com http://dnsimple.com/ Twitter: @dnsimple _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
