spf-discuss
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Re: *****SPAM***** Re: SPF is not usable as legal measure against spammers.

2004-07-16 07:53:14

----- Original Message ----- 
From: <administrator(_at_)yellowhead(_dot_)com>
To: <spf-discuss(_at_)v2(_dot_)listbox(_dot_)com>
Sent: Friday, July 16, 2004 10:26 AM
Subject: *****SPAM***** Re: [spf-discuss]SPF is not usable as legal measure
against spammers.


At 06:33 AM 7/16/2004 -0400, Stuart D. Gathman <stuart(_at_)bmsi(_dot_)com> 
wrote:

SPF, for one, demands that PTR's match the A record.  For that matter,
every internet application I've ever used ignores PTR records that do
not match any A record for the name.  Perhaps you known of some (made by
Microsoft?), but it is irrelevant since SPF specifically requires that
PTR
records match with an A record for the name.

***************** REPLY SEPARATER ******************
That's interesting, because it is a very common practice these days to
service many domains from one IP address (we currently service 10 virtual
email domains from one server). You can publish multiple PTR records, but
unfortunately there are many programs out there that only look at the
first
one. Reliably matching up the PTR to the "A" record is virtually
impossible.

J.A. Coutts

I don't see *anywhere* in the SPF specs that PTR must match the A record.
This is particularly true for hosts that have multiple A records. In fact,
it's legal to have multiple PTR records for a host. Once you start down
*that* merry road, you lose almost all chance of resolving a unique
hostname/PTR because you may be getting into loops.