DDNS, Notify and IXFR

[Masataka Ohta]

Paul;

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

Thank you. It's a problem between DDNS and NOTIFY.

> > 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.

Fix?

If update is done 4 times a second, it is likely that reference to
the updated and unupdated data is referenced a lot more frequently.

Instead, we can simply conclude that we can increment serial number as
frequently as we want, for which purpose, UDP IXFR is specified.

							Masataka Ohta