[101639] in North American Network Operators' Group
Re: houston.rr.com MX fubar?
daemon@ATHENA.MIT.EDU (Mark Andrews)
Mon Jan 14 22:24:24 2008
Date: Tue, 15 Jan 2008 14:23:25 +1100 (EST)
From: Mark Andrews <Mark_Andrews@isc.org>
To: nanog@merit.edu
In-Reply-To: <bb0e440a0801141838r736462dey64094e555cd6d0a6@mail.gmail.com>
Errors-To: owner-nanog@merit.edu
In article <bb0e440a0801141838r736462dey64094e555cd6d0a6@mail.gmail.com> you write:
>
>On Jan 14, 2008 5:08 PM, Tony Finch <dot@dotat.at> wrote:
>
>> the "." convention then it will look up the root's AAAA and A records,
>> which is stupid but should cause the message to bounce as desired. However
>> if it does implement the convention (just like the "usage rules" for a SRV
>> record target of "." in RFC 2782) then it can skip the address lookups and
>> save the root some work. (It can also produce a better error message.)
>> This really ought to be explained in draft-delany-nullmx.
>
>The draft died. And I think this stuff about looking up A / AAAA for
>the root was certainly raised in the IETF sometime back. Not that
>there isnt enough junk traffic (and DDoS etc) coming the roots' way
>that this kind of single lookup would get lost in the general noise ..
>
>Might want to revive it and take it forward? I rather liked that
>draft (and Mark Delany cites me in the acknowledgements as I suggested
>a few wording changes for the definition of a null MX - dot terminated
>null string, STD13 etc, during his drafting of the document)
>
>--srs
>
>--
>Suresh Ramasubramanian (ops.lists@gmail.com)
There are lots of places in the DNS where "." makes sense
as a null indicator. RP uses it today, as does SRV. MX
should use it and fallback to A should be removed. It
actually takes more cache space to record that a MX record
does not exist than it takes to record that a A or AAAA
record exists (SOA rdata is atleast 22 octets).
draft-ietf-dnsop-default-local-zones used it for SOA RNAME
but was changed under WG pressure.
A and AAAA should use 0.0.0.0 and :: to indicate that a host
exists but is not currently connected.
Mark
