IPv6 with 'a' or do we need 'aaaa' ? (Was: Re: Sending mail from dynami

On Wed, 2005-05-25 at 14:29 -0400, Constantine A. Murenin wrote:
> On 25/05/05, Bill Taroli <bill(_dot_)taroli(_at_)billsden(_dot_)org> wrote:
> > Constantine A. Murenin wrote:
<SNIP>

> I got it, thanks! The SPF syntax page is very difficult to find, and
> the description of what the SPF's 'a' directive does is somewhat
> unclear, at least to me. Something like "the hostname that is
> specified by the SPF's 'a' directive is resolved, and the resulting
> IP-addresses are tested against the client IP-address [of the MTA]".
> The keywords being here are "hostname is resolved". :-)
>
> As of today, the page <URL:http://spf.pobox.com/mechanisms.html#a> reads:
>
> "All the A records for /domain/ are tested. If the client IP is found
> among them, this mechanism matches."
<IPv6 whine mode>

But what about IPv6?

Either there has to be a identical 'aaaa' mechanism for doing IPv6 or
the 'a' mechanism gets redefined so that it requires apps to also check
for a valid IPv6 address. The latter is impossible because:

host.example.com/48 is IPv6, but what about host.example.com/24 IPv4 or
IPv6?

But the worst part, if you have any mechanism in the spf rule which is
not understood/supported by SPF the rule fails.

This leads people who require IPv6 to add a "~all" at the end, which
thus makes SPF quite, if not completely, useless.

Greets,
 Jeroen

(No closing tag indeed ;)

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