DNS question, null MX records

Brian Dickson Brian.Dickson at concertia.com
Wed Dec 16 14:44:54 CST 2009

I realize we're a bit off-topic, but to be tangential to the original topic, and thus barely relevant:

(Presuming the "sink.arpa." thing succeeds, big presumption I realize...)

So, how about using sink.arpa. as a(n) MNAME?

Or perhaps, one of the hosts listed in AS112?

Maybe a new AS112 entry that resolves to one of the IP addresses mentioned already ( and friends)?
(Too bad there isn't a reserved IP address that definitively goes to /dev/null locally. Or is there?)

Does an MNAME really need to be fully qualified?

Cute idea:  use the "search" of non-fully-qualified names, to direct bad UPDATE traffic to a very local server, e.g. "ns1" (no dot).

It would also be nice to have a place-holder in DNS that "resolves" (in the loose sense) to an appropriate pre-defined "thing", like the default nameserver for a client, or "yourself" for a resolver.

But I digress. :-)


-----Original Message-----

> When I attempted to document a similar idea (using an empty label in the =
> MNAME field of an SOA record in order to avoid unwanted DNS UPDATE =
> traffic) the consensus of the room was that the idea was both =
> controversial and bad :-)
> http://tools.ietf.org/html/draft-jabley-dnsop-missing-mname-00

Well UPDATE traffic is supposed to go to the nameservers listed in
the NS RRset prefering the MNAME if and only if the MNAME is a
nameserver.  Lots of update clients don't do it quite right but
there are some that actually send to all the nameservers.

Setting the MNAME to "." does not actually address the problem.


> Joe
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org

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