[Mimedefang] SPF
Matthew S. Cramer
mscramer at armstrong.com
Fri Nov 3 10:54:27 EST 2006
On Thu, Nov 02, 2006 at 12:34:59PM -0500, David F. Skoll wrote:
> Hi,
>
> After much consideration, I have removed the SPF record for
> roaringpenguin.com.
>
> SPF was supposed to help prevent "blow-back" from joe-jobs. (It
> was never designed to stop spam, of course, but I *was* hopeful that
> it would reduce annoying bounces caused by spam faked to come from
> our domain.)
>
> Alas, SPF has not lived up to its promise, and it has caused some
> problems for us (we have salespeople working on the road who send mail
> through their ISP's servers.)
>
> So, so long, SPF. Too bad you weren't useful.
We're still using a hard record so that Corporate can control where
all mail for our domains originates. We have a policy requiring all
email sent from our domains to go through Corp's smtp gateways - and a
hard SPF record helps us enforce it.
Of course we only notice when someone complains about a "problem"
of a bounced mail (from a recipient who honors SPF) originating from
their rogue SMTP server. But it has caught a few rogue servers and
Internet access points backdoored into some sales offices and
manufacturing sites.
For avoiding blow-backs from joe jobs, I reject any mail from <>,
postmaster, etc. that doesn't match a regex indicating there's a
quoted Received line with a legit smtp server's address.
Occasionally someone's stupid mail server sends DSNs with something
non-standard as a sender, but it is pretty infrequent.
Matt
--
Matthew S. Cramer <mscramer at armstrong.com> Office: 717-396-5032
Project Manager, Planning and Service Management Fax: 717-396-5590
Armstrong World Industries, Inc. Cell: 717-917-7099
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