Postfix is the mail transfer agent. It receives your mail and takes it into your correct mailbox after applying filters to your individual account. You pick up your mail via pop3 or imap etc.
amavisd-new has the following features:
- amavisd accepts mail from our MTA, pass it to ClamAV and SpamAssassin for checking, and then return it back to our MTA
- Amavisd-new, ClamAV and SpamAssassin can reside on a physically separate server than the MTA.
Installing ClamAV, Spamassassin, amavisd-new and postfix
yum install amavisd-new clamav clamav-devel clamd spamassassin postfix
Satrting spamassassin
service spamassassin start
Setup Requirements for amavisd-new
Edit the /etc/amavisd.conf
Edit the $max_servers to set the number of concurrent Amavisd-new processes and it must match the number set in /etc/postfix/master.cf “maxproc” column for the amavisd service
Global Settings for amavisd
$max_servers = 2; $daemon_user = "amavis"; $daemon_group = "amavis"; ... $inet_socket_port = 10024; ... # $notify_method = 'smtp:[127.0.0.1]:10025'; # $forward_method = 'smtp:[127.0.0.1]:10025'; $mydomain = 'techbabu.com'; $MYHOME = '/var/amavis'; $helpers_home = "$MYHOME/var"; $lock_file = "$MYHOME/var/amavisd.lock"; $pid_file = "$MYHOME/var/amavisd.pid"; $myhostname = 'mail.techbabu.com';
SPAM Settings for amavisd
$sa_tag_level_deflt = 2.0; $sa_tag2_level_deflt = 6.2; $sa_kill_level_deflt = 6.9; $sa_dsn_cutoff_level = 10; $penpals_bonus_score = 8; $penpals_threshold_high = $sa_kill_level_deflt; $sa_local_tests_only = 0;
ClamAV Settings for amavisd
['ClamAV-clamd',
\&ask_daemon, ["CONTSCAN {}\n", "/var/run/clamav/clamd"],
qr/\bOK$/, qr/\bFOUND$/,
qr/^.*?: (?!Infected Archive)(.*) FOUND$/ ],
Configure Postfix to allow mail to be passed to Amavisd-new for filtering and then reinjected back into Postfix
Edit /etc/postfix/master.cf to add following
amavisfeed unix - - n - 2 lmtp
-o lmtp_data_done_timeout=1200
-o lmtp_send_xforward_command=yes
-o disable_dns_lookups=yes
-o max_use=20
##### to reinject mail back into Postfix.
127.0.0.1:10025 inet n - n - - smtpd
-o content_filter=
-o smtpd_delay_reject=no
-o smtpd_client_restrictions=permit_mynetworks,reject
-o smtpd_helo_restrictions=
-o smtpd_sender_restrictions=
-o smtpd_recipient_restrictions=permit_mynetworks,reject
-o smtpd_data_restrictions=reject_unauth_pipelining
-o smtpd_end_of_data_restrictions=
-o smtpd_restriction_classes=
-o mynetworks=127.0.0.0/8
-o smtpd_error_sleep_time=0
-o smtpd_soft_error_limit=1001
-o smtpd_hard_error_limit=1000
-o smtpd_client_connection_count_limit=0
-o smtpd_client_connection_rate_limit=0
-o receive_override_options=no_header_body_checks, \
no_unknown_recipient_checks, no_milters,no_address_mappings
-o local_header_rewrite_clients=
-o smtpd_milters=
-o local_recipient_maps=
-o relay_recipient_maps=
enable message filtering in Postfix by adding the following setting to /etc/postfix/main.cf
content_filter=amavisfeed:[127.0.0.1]:10024
Running mail services
service postfix start service clamd start service amavisd start
Testing your configuration
$ telnet localhost 10024 Trying 127.0.0.1... Connected to localhost.localdomain (127.0.0.1). Escape character is '^]'. 220 [127.0.0.1] ESMTP amavisd-new service ready ehlo localhost 250-[127.0.0.1] 250-VRFY 250-PIPELINING 250-SIZE 250-ENHANCEDSTATUSCODES 250-8BITMIME 250-DSN 250 XFORWARD NAME ADDR PROTO HELO quit 221 2.0.0 [127.0.0.1] amavisd-new closing transmission channel Connection closed by foreign host.
It means amavisd is working properly.