J.P. Trosclair wrote:
Tuesday, October 21, 2008, 5:29:59 PM, Jim Balo ([EMAIL PROTECTED]) wrote:
Hi,
I am currently using Postfix w/ Amavis-new, Pyzor, DCC and Clam.
I have trained the Bayesian Classifier with over 2,000 ham and 2,000
spam, but I am still getting quite a bit of spam.
I am about to install a new mail server and I wonder if there is
something better than SpamAssassin that works well with Postfix?
The whole combination of Amavis, Pyzor, DCC, etc. seems a bit
complex and it also uses quite a bit of system resources.
I saw someone recommend policy-weightd, but that is no longer
developed since February 2008. I also came across ASSP, but I do
not know much about it yet.
Could someone recommend a really good open source or affordable
commercial anti-spam solution?
Thanks,
JB
Ps. Maybe it is just that I need to tweak SpamAssassin better?
Some good links on this would be helpful as well.
I haven't done gray listing personally, but I've seen good remarks made aobut
it here on the list and in other places. From what I've read it seems to be
very effective in stopping spam by itself (without spamassassin, et. al.) I've
contemplated implementing it here but the idea of any sort of delay in mail
being delivered doesn't sit well with the people who ultimately make the call
in what I can and can't do for reducing spam so we're stuck with spamaassassin.
I've used gray listing, but in the end abandoned it. Although it's
moderately effective on spam, it also removed email's immediacy, and was
completely undeliverable by some servers, which really annoys the users.
Some large organizations with multiple outbound servers will rotate
failed mail among the servers, which all have different IPs, and each
new IP will cause another greylist bounce. The mail will never get
through because by the time it's sent again by the original server,
there's a good chance it's greylist entry will have expired.
Although it's frowned on by some, I've had much better success using a
combination of RBLs and RDNS pattern matching to reject spam. Since a
huge proportion of spam comes from zombie networks that are identified
by DHCP addresses, a dozen or so regular expressions like these will
block a ton of spam.
Terry
---------------------------
smtpd_client_restrictions=reject_unknown_reverse_client_hostname . . .
check_client_access=regexp:/etc/postfix/spam_ip_regex
spam_ip_regex file:
/[ax]dsl.*\..*\..*/i 450 AUTO_XDSL Email Rejected. You appear to be
connecting from a Dynamic IP address.
/client.*\..*\..*/i 450 AUTO_CLIENT Email Rejected. You appear to
be connecting from a Dynamic IP address.
/cable.*\..*\..*/i 450 AUTO_CABLE Email Rejected. You appear to be
connecting from a Dynamic IP address.
/dial.*\..*\..*/i 450 AUTO_DIAL Email Rejected. You appear to be
connecting from a Dynamic IP address.
