Re: Re: More about the SPF RRTYPE

Sorry for the delay.

On 18/Aug/11 19:31, Murray S. Kucherawy wrote:
>> From: Alex van den Bogaerdt
>> 
>> TXT records with an _spf prefix is clearly a better approach than TXT
>> records without this prefix.
> 
> I think a lot of people would be happy if SPFbis said to use an
> "_spf" TXT record, and the various open source and commercial
> implementations evolved to comply.  People could leave SPF TXT
> records in the current location for transition purposes as long as
> they like, but we should explicitly deprecate that practice and
> encourage the new one.

I agree with Julian that we shouldn't force receivers to do yet
another discovery query.  (Rather, we should almost deprecate one.)
However, I have a couple of observations:

1.  SPF deployment seems to leave something to be desired for
    validating helo-names.  Anything that allows to publish a single
    record for all hosts should be taken into consideration.

2.  There is a noticeable deployment of _spf.domain already.  AFAIK,
    it is used by large mailers for inclusion by their clients.  We
    should explore and possibly document such practice.  Ideas?

>> The experiment could enter a new phase. There is no need for ASCII
>> characters in the SPF record. This means that for instance
>> "ip4:192.168.234.123" could be encoded in 5 octets instead of 19 plus 1
>> for a separating space. [...]
> 
> Some of this stuff might fly, if we do indeed move the TXT record,
> but we'll also need to come up with tools that the average sysadmin
> can use to generate a TXT record in a BIND zone file that matches
> the new specification.  The thought of doing this stuff in a
> conventional text editor will set a barrier to entry.

There's a draft for defining new types in /etc/rrtypes [L].  I propose
to postpone this discussion to when that language will be settled, so
that we can check whether it handles a binary type 99.

[L] http://tools.ietf.org/html/draft-levine-dnsextlang

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