[DNSOP] Comments on draft-ietf-dnsop-svcb-https

["libor.peltan" <[e-mail]>]

Hi all,

i'm a developer of Knot DNS authoritative server. I have some comments 
on the SVCB draft and some suggestions for improvements. Just consider 
my thoughts and then do whatever is best.

(1) The format of SVCB (and HTTPS) RR is too complicated, especially for 
parsing presentation format to wireformat and back, including 
consistency checks. Perhaps instead of

www 3600 IN HTTPS 1 . alpn=h2 port=8443

It could be

www 3600 IN HTTPS 1 . alpn h2
                   1 . port 8443

Which gives slightly bigger RRSet wireformat, but not by much.

(2) Paragraph 2.2 explicitly requires that SvcDomainName must not be 
compressed. Is there a reason? Especially when the response packets are 
large (and I expect that for SVCB they will), any compression helps.

(3) Paragraph 2.5 contradicts itself: "SvcDomainName MUST be the name of 
a domain that has SVCB, AAAA, or A records" versus "SvcDomainName MAY be 
the owner of a CNAME record". What is the meaning here?

(4) Let's assume that CNAME is allowed under SvcDomainName. Paragraph 
4.1 is too vague and I don't see what an authoritative (not recursive!) 
server shall answer in situation SVCB->CNAME->A (all in-bailiwick). 
Shall the CNAME and A be added to additional section? For comparison, in 
situation MX->CNAME->A we don't bother since this situation is forbidden 
(see RFC 2181).

(5) Wouldn't one octet for priority field be enough?

(6) There are not enough examples in the document. There are many 
variants of SVCB records, the formal ABNF description is difficult to 
read, and it would also illustrate what kind of services those records 
are designed to handle.

Best regards and thanks for your effort,

Libor Peltan
CZ.NIC