>>i think it makes more sense if the names of the files are shorter, as
>>the name of the "127" file is now.  others may feel otherwise.
>
>	hmm, i see your point but i'm not really convinced (decide zone file
>	hierarchy for the sake of short filename?).
>	are there any restriction/recommendation from DNS spec, or some others,
>	about defining zone file?

rfc1033 seems to name the zone files after the names of the networks.
thus, 10.0.0.0/8 would be called RESERVED-10 and 127.0.0.0/8 would be
called LOOPBACK.

rfc1537 says that "each nameserver should run primary for
0.0.127.in-addr.arpa; that zone file should contain a SOA and NS
record and an entry:

         1    PTR     localhost."

rfc1912 expands on this (and in the process obsoletes 1537) and says
(in more detail) that each nameserver should also have these zones:

           primary         localhost               localhost
           primary         0.0.127.in-addr.arpa    127.0
           primary         255.in-addr.arpa        255
           primary         0.in-addr.arpa          0

and about the localhost zone that:

   The "localhost" address is a "special" address which always refers to
   the local host.  It should contain the following line:

           localhost.      IN      A       127.0.0.1

the dns & bind book (o'reilly, albitz and lui) seems to call all the
files by "db." the zone name or "db." the network prefix.

so...there are no restrictions anywhere (except as might be limited by
your operating system, but that's not so much of an issue here :).
recommendations (if they can be called that) are made only by example.
they're never set forth in the manner of "here's how you should name
the file"; it's always been up to the reader.

as for me, i think the "db." thing is silly, so i've never used it.  i
also think that naming the files after the zones (as opposed to the
zone identifer names that internic/arin/iana/whoever assigns them)
makes more sense.

as for the ipv6 "reserved network" 0::0/8, i'm not quite so up to date
on what addresses fall where.  as you correctly pointed out, i'd
forgotten about the "this station" and the "ipv4 mapped/compat
addresses" that are also "in" that network.  is there anything else?
you seem to know *much* more than i do about ipv6...  ;]

ps - i guess you you could just name the file "0000::000", no?  :)

-- 
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