Problem w/ Forwarding Zone in Caching-Only Config

[Mark Andrews]

In message <alpine.DEB.2.11.1706281050330.31235 at grey.csi.cam.ac.uk>, Tony Finch writes:
> Mark Andrews <marka at isc.org> wrote:
> >
> > See https://tools.ietf.org/html/rfc6763 for details of how it is
> > designed to work.  Section 11 shows how to go from IP address and
> > netmask to the forward domain where the _dns-sd._udp subdomains
> > reside.
> >
> > lb._dns-sd._udp.0.43.168.136.in-addr.arpa PTR <A DOMAIN YOU CONTROL>
> 
> At Cambridge my colleagues have an experimental DNS-SD setup for printing
> from eduroam. Rather than the reverse DNS option, we're using the forward
> option where clients get the domain from DHCP, so I just needed to add a
> few records to the DNS and try not to worry too much about how competent
> the print server is at DNS. The forward option greatly simplifies wireless
> subnet allocation, and is conveniently v4/v6 agnostic.

The proceedure also works for IPv6 where for 99.99% of networks it
will be the reverse of the leading 64 bits.

e.g.
	lb._dns-sd._udp.0.0.0.0.0.0.0.8.B.D.0.1.0.0.2.IP6.ARPA

but these are all alternatives.

> $ORIGIN private.cam.ac.uk
> b._dns-sd._udp.wireless	 PTR pc-printer-discovery.wireless
> lb._dns-sd._udp.wireless PTR pc-printer-discovery.wireless
> pc-printer-discovery.wireless NS papercut-test.ds
> 
> Tony.
> -- 
> f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/  -  I xn--zr8h punycode
> Viking, North Utsire: Northerly or northeasterly 4, occasionally 5 in Viking.
> Slight or moderate. Fair. Good.
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org