Postfix/Spam_handling

From:

• http://archives.neohapsis.com/archives/postfix/2010-02/0075.html

• http://archives.neohapsis.com/archives/postfix/2010-01/0089.html

• Stop 70% or more of all spam with

  smtpd_recipient_restrictions =
     permit_mynetworks
     reject_unauth_destination
     reject_rbl_client zen.spamhaus.org

• Stop other zombies with greylisting, e.g., with postgrey.
• If the remaing spam bothers you, look into amavisd-new and other deep inspection systems. Use these only for mail that isn't cleaned via other means.

And some heavier duty options:

• Maintaining a local block-list

  I get one to two spams a day in the inbox these days, if that. Every few
  weeks or so I'll see 5-10 spams in the inbox due to a run from a previously
  unknown snowshoe spammer IP or /27 or /24 range.  I block it and sail mostly
  spam free again for another few weeks.

• Maybe ignore content filtering

  I don't use any content filtering software, period, only smtpd checks, postgrey
  daemon, and zen.spamhaus.org.  I filter about 10 countries and all of Africa
  using ipdeny.com cidr blocks and I do some rdns name regex rejections.

• Sample config

  header_checks = pcre:/etc/postfix/header_checks
  mime_header_checks = pcre:/etc/postfix/mime_header_checks
  smtpd_helo_required = yes
  cidr=cidr:/etc/postfix/cidr_files
  smtpd_recipient_restrictions =
         permit_mynetworks
         reject_unauth_destination
         check_recipient_access hash:/etc/postfix/whitelist
         check_sender_access hash:/etc/postfix/whitelist
         check_client_access hash:/etc/postfix/whitelist
         check_client_access hash:/etc/postfix/blacklist
         check_client_access regexp:/etc/postfix/fqrdns.regexp
         check_client_access pcre:/etc/postfix/ptr-tld.pcre
         check_client_access ${cidr}/countries
         check_client_access ${cidr}/spammer
         check_client_access ${cidr}/misc-spam-srcs
         reject_unknown_client_hostname
         reject_non_fqdn_sender
         reject_non_fqdn_helo_hostname
         reject_invalid_helo_hostname
         reject_unknown_helo_hostname
         reject_unlisted_recipient
         reject_rbl_client zen.spamhaus.org
         check_policy_service inet:127.0.0.1:60000