spf-discuss
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Re: [spf-discuss] Exclusive v. Open SPF records

2005-09-05 19:28:11
On Tue, 6 Sep 2005, Jasper Wallace wrote:

On Sun, 4 Sep 2005, Stuart D. Gathman wrote:

SOFTFAIL is for debugging, before switching to -all.  Receivers
are encouraged to send feedback (via DSN) for SOFTFAIL.  When you
get a SOFTFAIL DSN for a legit message, you have just found a bug
in your policy.

Or you've found a forwarder who dosn't do SRS.

If I send an email through a forwarder that dosn't do SRS, and if the
recipient has strict SPF checking, my email will discarded.

NO NO NO.  It will not be discarded by correctly implemented
receivers.  Yes, a braindead receiver might discard your mail
for any number of stupid reasons.  

1) Discarding on SPF FAIL without whitelisting non-SRS forwarders is certainly
one of the stupider.

2) I've never seen even the most braindead receiver DISCARD mail
on SPF FAIL.  They would typically REJECT the mail.  Then you
can just get their real email from the DSN and resend.

3) Actually, I've seen very few braindead receivers over the year I've been
publishing SPF.  I think it is largely a legend created by
the "SPF breaks forwarding crowd".

4) When you find a braindead receiver, tell them how to fix it.
(Create a domain with no SPF record to send from, or use their
real email gleaned from the DSN.)

When I can be fairly confident that any random recipient I send mail
to will not go thorugh a forwarder that dosn't do SRS, then I can change
to -all.

The forwarder does NOT have to do SRS to get your mail delivered.
That is just *one* way for receivers to manage their forwarders.
Simply whitelisting them works too. 

I'm not sure that SRS is that useful for forwarding.  A receiver
*still* has to whitelist their forwarders - because spammers do SRS
just fine.  So if you have to whitelist them anyway, SRS doesn't
buy you anything.

SRS is useful for blocking forged bounce spam.  

-- 
              Stuart D. Gathman <stuart(_at_)bmsi(_dot_)com>
    Business Management Systems Inc.  Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flamis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.

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