We excluded them (and other swiss providers) from DNSBL and SPF tests a long
time ago.
Many of our customers thwart SPF by using various dial-up/dsl/cable accounts
to send mails from their company sender address.
Here is a rough overview of our spam deflection/recognition:
Greylisting 66%
DNSBL 9%
SURBL 7%
Checksum Service (Massmail-Recognition) 5%
SPF 3%
Leaving about 10% incoming "ham" mail.
We do not use Bayes, Heuristic and Bad word lists because they caused too
much false positives and require intense maintenance.
We use the antispam software XWall in front of our IMail server. It can
verify the recipient addresses with the backend server by LDAP or by static
userlist.
Regards, Marius
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Martin Schaible
Sent: Monday, March 13, 2006 4:35 PM
To: Ipswitch IMail Mailing List
Subject: [IMail Forum] Dealing with free mail services and spam
Hi,
I'm looking for a kind of a best practice to deal with free mail services
and spam. Our local (swiss) Freemail companies are blacklisted on one or
more DNSBL.
Now with the help of mxGuard, it's more easier to deal with DNSBL since we
have a scoring system.
Mostly all mails from those free mailers are captured as spam, they reach
the score to treated as HIGH. But our local free mailers are more or less
spam free.
For all swiss members of this list: I'm talking about hispeed, bluewin and
swissonline.
I'm a bit unsure, if it's a good idea to whitelist those companies and trust
only to the phrase list from IMail.
How do you deal with your (local) free mailers?
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