bind 9.6.1-P2.
I've dumped it to its file.
$ sudo rndc dumpdb
$ cat named_dump.db
...
; Unassociated entries
;
; 10.0.0.3 [srtt 610620] [flags 00002000] [ttl 1721]
; 10.0.0.2 [srtt 16654] [flags 00002000] [ttl 1721]
; 10.0.0.1 [srtt 375289] [flags 00002000] [ttl 1721]
...
So I can assume that srtt with the lowest value has the best metric? And the
ttl of 1721 is the timeout of 1.7 seconds? Am I reading that right?
On Mon, Apr 19, 2010 at 4:26 AM, Cathy Almond <cat...@isc.org> wrote:
> A long time ago it used to be in turn, but all current versions of BIND
> sort the forwarders based on a preference value (SRTT) that's derived
> from the RTT of previous query/query response interactions, with a 'time
> since we last tried this server' incorporated so that servers that
> aren't top of the preference list are periodically re-used. It also
> means that if a server becomes unavailable, it gets time-penalised and
> therefore the others of the group will be used instead until the penalty
> has decreased over time - at which point, if it's back and running once
> more then it's going to be selected (or not) as before on 'nearness'.
>
> You can see the SRTT value of nameservers in the ADB section of the
> cache dump (from rndc dumpdb). Smaller values are preferred.
>
> What version are you using?
>
>
> Jonathan Reed wrote:
> > I have the forwarders statement to fwd queries to a few DNS servers on my
> > LAN.
> > forwarders { 10.0.0.1;
> > 10.0.0.2;
> > 10.0.0.3; }
> > The bind documentation says that these fwders are queried "in turn", but
> > what exactly does that mean? I understand it to mean that they are not
> round
> > robined and if the answer is found from the first IP then it stops there
> and
> > returns the query to the client. But assume that .1 goes unreachable.
> What
> > is the timeout used to query the next forwarder in the list? And is this
> > timeout modifiable?
> >
> >
> >
> > ------------------------------------------------------------------------
> >
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>
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