Bind 9 and IBM AIX 4.3.3 IP V6 reverse loopback resolution

Mark_Andrews at Mark_Andrews at
Thu Jan 9 22:37:12 UTC 2003

> in comp.protocols.dns.bind i read:
> >>   $ttl 1d
> >>   @ 1d soa localhost. root.localhost. 1 1d 1h 1w 1d
> >>     1d ns  localhost.
> >>     1d ptr localhost.
> >	Don't use "localhost." as the nameserver as it will result
> >	in the root servers being queried for A/AAAA addresses
> >	unless you also have a "localhost." zone (the actual queries
> >	made are version dependent).
> always do, along with zones for all rfc-1918 and known invalid or reserved
> tld's (.invalid).
> >	Do use the name of the machine that is serving the data.
> >	This puts the load causes by additional data lookup where
> >	it rightly belongs.
> localhost *is* the name of that machine.  one might argue that it is merely
> one of it's names and not as specific as (one of) the other(s), but it is
> it's name.

	"localhost." does not (officially) exist in the global DNS.
	"localhost." MAY exist on *your* machine but when giving
	advice it is much better not to make the assumption that
	it exists.  I don't have a "localhost." zone, I use localhost
	entries in the zones listed in the search list to allow
	"localhost" to resolve.

	(A "localhost." zone has from time to time been configured on
	some of the roots.  However it does not exist in the root zone
	or on all of the root servers so it does not officially exist.)

	Queries for "localhost." form a significant part of the root
	servers load.

> >	Do use a real contact address in case the entries leak and
> >	cause problems.
> hmm.  that does seem sensible.  i'll switch that.
> >	Whan giving example use numbers rather than BIND specific
> >	extensions.
> why, this is bind-users not comp.protocols.tcp-ip.

	People use the examples on more that BIND.  You will note
	the while BIND 9 reads them it doesn't emit them.


> -- 
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Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at

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