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Re: [RFC 1464?] RE: Alternative to TXT or new RR was: Comments ondraft-ietf-marid-core-01 xml use

2004-06-11 13:11:54

On Fri, Jun 11, 2004 at 02:39:49PM -0500, Gordon Fecyk wrote:
No one's brought up RFC 1464 yet, which describes how to store unique and
arbitrary information in TXT records in DNS.  SPF does this, DMP does this.
It avoids the TXT record collision problem by describing a unique attribute
name along with a value for the attribute.

We used it for an early draft of MTAMARK (MTA=yes and MTA=no) and gave up
on it (after some helpful discussion with Arnt Gulbrandsen):
------------------------------------------------------------------------
   Storing arbitrary string attributes in the Domain Name System
   [RFC1464] is a technique described and used at least since 1993. One
   solution that we took into consideration has been to store string
   attributes like "MTA=1" or "MTA=0" at the same level as PTR records.

   However this method does not support specific queries and has a high
   overhead for parsing the responses, is prone to naming collisions and
   will trigger errors and problems in old implementations of DNS
   servers with the 512 byte size limit.
------------------------------------------------------------------------

With the above you would ask "gimme all your TXT records" and choose
which one suits you. Asking for e.g. _marid.example.org is an exact
and specific question with (if configured correctly) exactly one answer.

        \Maex

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