DDNS, Notify and IXFR

[Paul A Vixie]

> The issues Kevin raised are not the fault of the IXFR protocol.

agreed.

> They are due to interactions between BIND's implementations of
> deferred serial number update, NOTIFY, and IXFR.  Changing the
> implementation, for example by rate-limiting NOTIFY generation, should
> solve the problem.

notify is supposed to be rate-limited (its rfc recommends this, anyway).
some parts of bind (like after the master has reloaded) have a delay,
but other parts don't, and neither part rate-limits.  8.2.2 will fix this.