BIND 9.4.x empty zones
Mark_Andrews at isc.org
Wed Oct 31 23:54:38 UTC 2007
> I have been looking at the new "built-in empty zone" stuff in 9.4.x
> (specific experiments with 9.4.2rc1), partly with a view to getting
> our production 9.3.x setup in line so that the transition is not too
> traumatic. Comparing them with the "server information" (class CHAOS)
> "version.bind" zone and friends is also instructive.
You may want to look at the draft-ietf-dnsop-default-local-zones
drafts and discussions in the dnsop working group.
> Here is a summary of what I have found so far, with some questions
> 1. SOA.mname (and single NS record) has the same name as the zone
> (modifiable for the empty-zones by the "empty-server" option,
> fixed for the server-info zones). Does this actually make sense?
> Maybe it's just harmless.
The default is answered by the empty zone itself.
> 2. SOA.rname is "." for empty-zones (modifiable by the "empty-contact"
> option) but "hostmaster.[zone-name]" for the server-info zones
> (not modifiable). I actually rather like the idea of "." as
> indicating "there isn't any contact address, get lost", but can
> that be justified from the RFCs?
There was lots of discussion over this one.
> 3. The remaining SOA parameters are fixed at "0 28800 7200 604800 86400"
> for both sorts of zones. I suppose only the negative TTL might be
> something one could conceivably want to modify.
> 4. Queries against the empty-zones seem always to be allowed, while those
> against the server-info zones respect the "allow-query" setting in
> the "options" statement. This seems to me to be a bug.
This one needs to be addressed.
> 5. Zone transfers on either sort of zone seem never to be allowed, but
> exactly what errors one gets and how or whether they depend on the
> "allow-transfer" setting in the "options" statement is currently
> still obscure to me.
> One additional issue that occurs to me is whether onew should try and
> make one's almost-empty zones "localhost" and "0.0.127.in-addr.arpa"
> (traditional here, at least, but maybe one should go with blocking
> the whole of "127.in-addr.arpa" in line with 9.4.x) look like the new
> empty-zones in respect of SOA & NS contents.
127/8 is how the address space is allocated.
> And also, why doesn't the built-in empty-zones list include
> "0.in-addr.arpa" and "255.in-addr.arpa" (also traditional here)
> or at least enough to cover reverse lookups on IPv4 addresses
> 0.0.0.0 and 255.255.255.255?
0.IN-ADDR.ARPA is just missing.
255.255.255.255.IN-ADDR.ARPA covers the broadcast address
> That's enough for now ;-)
> Chris Thompson
> Email: cet1 at cam.ac.uk
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: Mark_Andrews at isc.org
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