Postfix spam prevention by use of blacklists.

I switched my hosting servers to Centos 7 a couple years ago, my postfix instance has been a fun experiment for the past year or so.

Below see the instance of “Blocked using” in my maillog file.  The dips are when I was not using any, and the peaks are when I was using one, or many blacklist providers.   I’ve heard good things about the barracuda blacklist, so I’ll add that eventually, and watch for spikes.

 

Blocked Using 2017 Graph
Blocked Using 2017 Graph

 

Important parts of my main.cf

smtpd_recipient_restrictions =
permit_sasl_authenticated,
permit_mynetworks,
check_recipient_access mysql:/etc/postfix/mysql-virtual_recipient.cf,
reject_unauth_destination,
reject_invalid_hostname,
reject_non_fqdn_hostname,
reject_non_fqdn_sender,
reject_non_fqdn_recipient,
reject_unknown_sender_domain,
reject_unknown_recipient_domain,
reject_rbl_client bl.spamcop.net,
reject_rbl_client sbl.spamhaus.org,
reject_rbl_client cbl.abuseat.org,
reject_rbl_client dul.dnsbl.sorbs.net,
permit

 

RobPatton

I'm kind of a big deal.

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