Posted on 2005-03-18
I'm studying "DNS on Windows Server 2003" (O'Reilly 2004) to get a final grip on DNS.
As I understand it, now, a forwarding name server will use its forwarders first (given it can't resolve the query with cache or zone data), and if the forwarders are unreachable, the forwarding name server will go for the root hints. That's how I understand the following:
"...the [forwarding] name server sends the query to its configured forwarders and waits a short period for an answer before resuming normal operation and contacting the remote servers itself. What the name server is doing that's different is sending a recursive query to the forwarder, expecting it to find the answer. At all other times, the name server sends out nonrecursive queries to other name servers and deals with responses that refer only to other name servers." (p. 230)
There's the option to make the forwarding name server a "forward-only name server", by checking the "Do not use recursion for this domain" box in the Forwarders configuration tab (a check box with "confusing terminology", but never mind). The writers say:
"If you want to restrict your name servers even further -- stopping them from even trying to contact an off-site server if their forwarder is down or doesn't respond. You can do this by telling the server not to fall back to using the recursive resolution process if no forwarders respond: check the "Do not use recursion for this domain" box on the "Forwarders" configuration tab." (pp. 231-232)
My question concerns this sentence: "You can do this by telling the server not to *fall back to using the recursive resolution* process if no forwarders respond..."
Shouldn't it say: "... fall back to using the *nonrecursive* resolution." As I understand it, if the forwarders aren't responding, the forwarding name server will use the root hints, and the root hints query is by definition nonrecursive.
Am I right?