blackhole and allow-transfer

[Barry Margolin]

In article <a8ftuv$t7f at pub3.rc.vix.com>,
Kevin Darcy  <kcd at daimlerchrysler.com> wrote:
>Note that even if allow-transfer "overrides" blackhole, you'll still have=
> a
>problem with serial-number queries from the slaves to the master, since t=
>hose
>are seen as just "ordinary" queries and thus would be blackholed. So you'=
>d
>better hope that all of your NOTIFYs are received in a timely fashion, an=
>d
>you'd better make sure that all of your stealth slaves are mentioned in a=
>n
>also-notify clause.

The notify mechanism wouldn't help.  After receiving the notify, I believe
the slave just goes into the same routine that runs when the Refresh timer
is reached.  It performs an SOA query to make sure the serial number is
higher (masters often send out unnecessary NOTIFY messages, e.g. when they
start up they will send a NOTIFY about every zone (8.3.x has an option to
prevent this)).  So if the slave receives a NOTIFY, but no response to its
SOA query, it still won't transfer the zone.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Woburn, MA
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