Hi,

There are a number of spammers who are using domains with no SPF record to
get their mail through, with forged sender address domains that don't even
match the IP addresses they are coming from.  There are countless domains
with no SPF and when none is present, ASSP doesn't appear to do any checks
to see if the claimed domain matches the sender.  Doing reverse lookups for
PTR (DoPTRCheck) and MX (DoMXACheck) helps in some cases, but many times
those records are present and do not add to any penalty scoring.  For the
most part, these are the only emails that are getting through our ASSP
installation.

With this in mind; if the sender address is forged and there is no SPF
record to validate the forgery, a penalty score should be imposed,
especially when a reverse lookup for PTR is being performed.

Since most legitimate domains have an SPF record, I've tried to use the "SPF
NONE" (spfnonValencePB) setting in an attempt to catch more of these SPF
missing emails by treating them with extreme prejudice, but that doesn't
appear to be working correctly.  If "Fail SPF None Responses" (SPFnone) is
checked, messages claiming to come from domains with a missing SPF are
scored by "SPF Failed" (spfValencePB), instead of "SPF NONE"
(spfnonValencePB).  If "Fail SPF None Responses" (SPFnone) is not checked,
no penalty score is imposed for a missing SPF record at all.

Phil Quesinberry
Q Systems Engineering, Inc.
Electronic Controls and Embedded Systems Development
(410) 969-8002
http://www.qsystemsengineering.com

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