On Tue, 24 Oct 2006, Jerry Geis wrote:
Gents,
I have added the following to /etc/mail/sendmail.mc and rebuilt it trying to control spam. I still get about 25 spam messages a day. Is there something else that can help control spam?
CentOS provides spamassassin 3.0.6, but I've installed spamassassin 3.1.7 and spamass-milter from rpmforge. Running your spam scanner as a milter allows you to reject egregious during the SMTP transaction.
I haven't done as much tuning as I'd like, but my current setup includes
INPUT_MAIL_FILTER( `clamav-milter', `S=local:/var/clamav/clmilter.sock, F=T, T=S:3m;R:3m') INPUT_MAIL_FILTER( `spamassassin', `S=unix:/var/run/spamass.sock, F=, T=C:15m;S4m;R:4m;E:10m') define( `confMILTER_MACROS_CONNECT', `b, j, _, {daemon_name}, {if_name}, {if_addr}') FEATURE(`dnsbl', `sbl-xbl.spamhaus.org', `"554 Mail rejected - http://www.spamhaus.org/query/bl?ip=%22$&%7Bclient_addr%7D')
The percentage of messages rejected during SMTP transactions breaks down (for me) like this:
74% == spamhaus 21% == spamassassin 2% == unresolvable sender domain <1% == clamav
There's a range of spam (scores 5.0 - 10.0) that's accepted for delivery but marked as spam; people can procmail those as they see fit.
I think the spamhaus numbers get inflated because the sending servers are typically bots that are set to try delivery several times before giving up.