I'm doing an early review of draft-ietf-core-dns-over-coap
for the DNS Directorate.  This is only an early review.

Status:  On the right track, but should have another review or reviews
as it reaches WGLC status.

While this draft is focused on the communication between a DNS-over-CoAP client
and DNS-over-CoAP server, the communication between the DNS-over-CoAP Server 
and the "DNS Server" is done using DNS-over-DTLS, which the DNS community has
not seen implementations in use.  The whole communication between the 
the DoC Server and the "DNS Server" should be expanded upon.   

The document talks about "DNS Server" but it needs to be more precise - is this
a DNS Recursive Resolver, Stub Resolver or DNS Authorative Server?  The document
needs to be more precise about this.  Please see 
https://www.rfc-editor.org/rfc/rfc8499#page-16 for more details. 

Before WGLC, from the DNS perspective a working implementation for observation.
While the authors and WG may feel that this DNS interaction will be 
constrained to the CoAP environment, but those who operate DNS
infrastructure will feel this may be wishful thinking.