NS Round Robin?
Joseph S D Yao
jsdy at cospo.osis.gov
Tue Nov 16 20:30:47 UTC 1999
On Mon, Nov 15, 1999 at 11:22:26AM -0600, Rich Phillips wrote:
> In the whois response below. There are 4 nameservers listed. They are
> "listed in order" according to the whois response? The thought was these
> nameservers actually will respond in a round robin scenario. But it doesn't
> appear that the actual whois response flip flops the servers, like a regular
> My thoughts are that the whois response is giving simply a database
> response. It even looks as if they are in alpha/numeric order?? When a
> domain is queried, it goes to the appropriate root, resolves the appropriate
> domain, and which ever NS record is on the top, then that is the one that is
> given to the resolver.
You are confusing two things.
Yes, the "WHOIS" response is simply a database lookup. Said database is
NOT tied in with the DNS name servers, except that both are supposed to
be set up from the same initial data. But I have seen instances of
WHOIS data being different from data gleaned from name servers. Not
supposed to happen, but it does.
DNS "round robin" has absolutely nothing to do with the responses you
see pulled out in response to a WHOIS request. DNS queries do not go to
the WHOIS database!
> The specific concern is that if the Primary is not listed first(in the whois
> query), then it could mess up queries that would be sent for a particular
> nameserver. I don't think that this is correct, and need additional
> information to verify my position.
It should make no difference. EACH and EVERY name server for a domain
must act to the client as if it were THE server, the ONE AND ONLY name
server, the AUTHORITATIVE name server. Otherwise, the whole thing
breaks down. Resolvers are only going to query one server - the first
one they happen to find. [This is where DNS "round robin" comes into
play.] Resolvers, if not satisfied at one server, are still NOT going
to "shop around" and look for another server. To the resolving client,
there IS no "primary" and "secondary".
Among themselves, of course, name servers know to whom they should refer
to get valid data in a master-slave relationship.
Joe Yao jsdy at cospo.osis.gov - Joseph S. D. Yao
COSPO/OSIS Computer Support EMT-B
This message is not an official statement of COSPO policies.
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