Am 19.09.2015 um 00:57 schrieb Bruce Marriner:
On Friday, September 18, 2015 04:59 PM CDT, "Bill Cole"
<[email protected]> wrote:
On 18 Sep 2015, at 14:29, Bruce Marriner wrote:
So I want to be able to set up Postfix so, if it passes DKIM or other
checks that give me a high confidence then just skip the postgrey
stuff
entirely.
In what exactly does a valid DKIM signature give you high confidence? I
suspect that this is misplaced...
All a DKIM signature validation tells you is that a message was in fact
signed at the mail system where it claimed to have been signed by an
entity in control of the DNS for the domain identified the signature and
that none of the message fields specified in the DKIM header have been
changed in transit. Looking at the spam that has made it through my
filters this year, I see that 27% of those messages had a valid DKIM
signature, because in fact any spammer who can open a Yahoo account or
register a domain can send mail with a valid DKIM signature.
Ah, well. I think you might be right about misplaced. I've been reading about
this all day learning it and I've started to realize the same thing. I would
like
Now, why can't all the spammers just add a ThisIsSpam header. Sure would make
my life easier :)
I'd still like to reduce my dependency on postgrey. So, if has valid SPF, valid
DKIM, has a low SpamAssassin score, <insert other possible test heres> then I
could skip it without raising spam too much, or at all :).
Postgrey just works so well :) I mean, if I have that on I get almost no spam.
But sometimes somethings that should come though don't and many things are
delayed. When I turn it off, I get tons of spam.
So, I need to start adding more stuff into the mix like SpanAssassin, SPF,
DKIM, whatever so I can reduce my Postgrey dependency a little.
My first few google searches were covered in the DKIM/SPF stuff so I guess
that's where I've started first.
We are using Postfwd[1] to conditionally use Greylisting when the sender
seems suspicious. There is already a good example configuration for
"Selective greylisting".
[1] http://postfwd.org/
--
Alex JOST
