Secondary refresh tuning

[Don Stokes]

phn at icke-reklam.ipsec.nu wrote:
>> Would 400 or so defunct primaries stop an active zone being updated
>> immediately if a notify for it was received?
>
>Why don't you remove or comment out those 400 ? Noone is happy with 
>non-working zones.

Because I can't put my hand on my heart and say they'll stay
non-working.  Many of them are "parked" domains, and the annoying thing
about a parked domain is that while the owner may not have cared about it
all year, they might decide tomorrow that they need to use the domain,
and fix the configuration.

Hence the approach of just probing these occasionally.

I did toy with the idea of removing such domains from the configuration,
and then periodically probing the removed domains from an external
program, along with doing all AXFRs from an external procedure and
running master zones from the AXFRed data.  

-- don