Min/Max Refresh and Notify

Mark Damrose mdamrose at elgin.cc.il.us
Fri Dec 13 17:32:22 UTC 2002


"Kevin Darcy" <kcd at daimlerchrysler.com> wrote in message
news:atd4tb$3ui6$1 at isrv4.isc.org...
>
> Mike Diggins wrote:
>
> >I have a slave name server configured with a zone using min and max
> >refresh time.
> >
> What do you mean by "min and max refresh time"? There is only one
> REFRESH field in an SOA record.
>
> >I was using it to limit the number of times the zone updates
> >to just two times a day.
> >
> >Question: If the master name server is configured to send notifies to the
> >slave when an update to the zone occurs, will the slave update the zone
> >anyway? That appears to be what's happening but I want to be sure. If it
> >is true, would turning off notifies to that slave for that one zone stop
> >that from happening?
> >
> Yes, you could turn off NOTIFYs and that would greatly reduce the number
> of refresh checks that the slave performs. But, be aware that the
> frequency with which BIND slaves perform refresh checks has a random
> element to it. This is done deliberately to prevent slave "cycling"
> which causes spikes of refresh-check and/or zone-transfer activity. So
> you can never *exactly* control when the slave will perform
> refresh-checks when you rely on the REFRESH setting alone.
>
> Perhaps you might consider turning off NOTIFYs to the slave within BIND
> and then using an artificial non-BIND method of sending NOTIFYs to the
> slave at specific intervals. I seem to recall there was a utility out
> there that could generate NOTIFYs, but I don't have a pointer to it
> handy. Perhaps someone else on the list could provide that information...

Haven't tested it, but this looks like it would do it.
http://tinydns.org/dnsnotify




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