resolv.conf question
Ralf Hildebrandt
Ralf.Hildebrandt at innominate.de
Thu Jun 15 07:12:20 UTC 2000
> Ralf> My question: Is there any way to automatically reorder the
> Ralf> server in such a way, that query time is optimal?
>
> No. And even if there were, few applications would be able to exploit
> it. Most applications make 1 DNS request - maybe repeated to 2 or 3
> name servers - and then don't do another DNS lookup after they've got
> the answer.
?
I thought the programs would use resolver routines, and the resolver would
take care of the resolution itself.
So the resolver would have to keep track of the reachability (like xntpd)
> So keeping track of the round trip times would be
> pointless for most things that use the DNS. The rotate option in the
> BIND8 resolver might help a little, but only for the handful of
> applications which make lots of DNS lookups. And even then this only
> round-robins queries between the three nameserver directives, so the
> bad name server(s) still get queried.
What exactly is the name of that option (so I can look it up in the docs)?
> Ralf> Reason: We had several customers complaining about bad
> Ralf> performance, and one of the main resons was that the
> Ralf> nameservers in their /etc/resolv.conf's were not answering
> Ralf> their machine's queries.
>
> Why not get those customers to set up their resolvers to point at
> reliable name servers? That would be the simplest and most obvious
> solution. It seems a bit silly to fire DNS lookups at name servers
> that don't respond.
Well, they USED to respond...
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