Cloud DNS providers for secondary DNS

[John Levine]

>My more specific question is this: If I'm a site on the internet looking for a server in my domain for the first time, I query the TLD
>servers for a list of name servers for my domain and pick one to query. Suppose I pick one that has the correct zone information and can
>answer the query, but that specific NS is not listed in the zone record. I believe that's called a LAME nameserver, correct?

Not sure I understand your question.  If you're looking for, say,
www.blah.example, you (actually your DNS cache that does the recursive
lookups) ask the example TLD servers for www.blah.example, and it
answers with some NS records that say that the blah.example domain is
handled by some set of servers.  Then the cache looks up the address
of one of the servers if it doesn't have it already, and asks it for
www.blah.example.  If the server doesn't know the answer, i.e., it
doesn't handle the blah.example zone, that's a lame delegation.  At
that point most caches will try other servers to try and find a
non-lame one so it's not fatal, but it's not a great idea either.

Extra complication ensues when the server's name is within the zone,
e.g., the server for blah.example is ns.blah.example.  In that case,
the A or AAAA record(s) for ns.blah.example are copied into the upper
level zone (the TLD in this case) as "glue" that are returned in the
additional section of the answer, so caches can use it to handle the
request.

R's,
John