DNS and Bind Recrusion page 39 (3rd edition)

[Edmund]

Thanks.  I asked this question because my old BIND 4.9 running in
SUN OS doesn't seem to do this job well and always return a
timeout.


Barry Margolin wrote:

> In article <37CF2F0D.39A107C at hk.china.com>,
> Edmund  <c990077 at hk.china.com> wrote:
> >Since it's concerning recursion query, I've a question regarding local
> >name server recursion query to a Root name server.  If a local name
> >server got a timeout error when querying a Root name server, it will
> >usually return the same error to its client.  Is there any way to avoid this
> >error and will the local name server query another Root name server
> >next time instead of the previous timeout Root name server ?
>
> The server should try another root server.  The problem may be that by the
> time the server does this and then performed the additional iterative
> queries to the destination domain server, your resolver may have timed out
> waiting for a response, so you'll get an error in your application.  The
> typical symptom of this is that you try again to look up the name and it
> works immediately.
>
> This shouldn't happen much.  The local name server keeps track of server
> response times, and queries the ones that have the best response.  If it
> times out querying a root server, it should not become a candidate for a
> while.
>
> --
> Barry Margolin, barmar at bbnplanet.com
> GTE Internetworking, Powered by BBN, Burlington, MA
> *** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
> Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.