[dns-operations] 答复: 答复: DNS forwarder behavior on response with cname

Dave Lawrence tale at dd.org
Thu Jan 3 20:18:41 UTC 2019

Davey Song(宋林健) writes:
> It sounds to me that the forwarder is highly suspicious on the
> answer got from the upstream resolver which is chosen by the forward
> itself.

I'm wondering whether this is just an artifact of the BIND resolution
algorithm with regard to query restarts on CNAMEs from authorities.
Even when it gets "foo.example.com CNAME bar.example.com" followed by
the relevant records for example.com, it is actually possible for
bar.example.com to be under a different authority.

I'm fairly sure I have somewhere deep in my mail archives a message
from Mark Andrews citing RFC 1034 3.6 as to the necessity of
restarting the query.  This was in response to a suggestion that the
restart should be skipped if the name was (apparently) in-bailiwick,
and declining to make that change.

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