Mail filtering and improving the score of sending email

Resources:

1) Ubuntu – Mail Filtering
2) Ubuntu – PostfixAmavisNew

The recommended and easiest way to install Pyzor is with pip:

root@ubuntu:~# pip install pyzor

In order to upgrade your Pyzor version run:

root@ubuntu:~# pip install –upgrade pyzor

For me, the latest pyzor-1.0.0 seemed to not working on my environment.

Ubuntu 16.04.3
Postfix 3.1.0
Dovecot 0.4.13
SpamAssassin version 3.4.1 running on Perl version 5.22.1
Amavisd-new-2.10.1 (20141025)
Python 2.7.12

Pyzor-1.0.0 was come up with some error, like this:

Traceback (most recent call last):
File “/usr/local/bin/pyzor”, line 4, in <module>
__import__(‘pkg_resources’).run_script(‘pyzor==1.0.0’, ‘pyzor’)
File “/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py”, line 739, in run_script
self.require(requires)[0].run_script(script_name, ns)
File “/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py”, line 1486, in run_script
raise ResolutionError(“No script named %r” % script_name)
pkg_resources.ResolutionError: No script named ‘pyzor’

So, I decided to use Pyzor-0.9.0, hopefully it’s working well.
Hereby is how I start pyzor:

root@ubuntu:~# wget https://<find the source link from internet, please>/pyzor-0.9.0.tar.gz
root@ubuntu:~# tar xvf pyzor-0.9.0.tar.gz
root@ubuntu:~# cd pyzor-0.9.0
root@ubuntu:~# python setup.py build
root@ubuntu:~# python setup.py install

Make sure that you enable spamassassin, and check out Amavis’s configuration

root@ubuntu:~# vi /etc/default/spamassassin

# /etc/default/spamassassin
# Duncan Findlay

# WARNING: please read README.spamd before using.
# There may be security risks.

# If you're using systemd (default for jessie), the ENABLED setting is
# not used. Instead, enable spamd by issuing:
# systemctl enable spamassassin.service
# Change to "1" to enable spamd on systems using sysvinit:
ENABLED=1

# Options
# See man spamd for possible options. The -d option is automatically added.

# SpamAssassin uses a preforking model, so be careful! You need to
# make sure --max-children is not set to anything higher than 5,
# unless you know what you're doing.

OPTIONS="--create-prefs --max-children 5 --helper-home-dir"

# Pid file
# Where should spamd write its PID to file? If you use the -u or
# --username option above, this needs to be writable by that user.
# Otherwise, the init script will not be able to shut spamd down.
PIDFILE="/var/run/spamd.pid"

# Set nice level of spamd
#NICE="--nicelevel 15"

# Cronjob
# Set to anything but 0 to enable the cron job to automatically update
# spamassassin's rules on a nightly basis
CRON=0

root@ubuntu:~# vi /etc/amavis/conf.d/15-content_filter_mode

# This file was automatically installed on 2018-01-09T15:20:07.018374
use strict;

# You can modify this file to re-enable SPAM checking through spamassassin
# and to re-enable antivirus checking.

#
# Default antivirus checking mode
# Please note, that anti-virus checking is DISABLED by
# default.
# If You wish to enable it, please uncomment the following lines:

@bypass_virus_checks_maps = (
   \%bypass_virus_checks, \@bypass_virus_checks_acl, \$bypass_virus_checks_re);

#
# Default SPAM checking mode
# Please note, that anti-spam checking is DISABLED by
# default.
# If You wish to enable it, please uncomment the following lines:


@bypass_spam_checks_maps = (
   \%bypass_spam_checks, \@bypass_spam_checks_acl, \$bypass_spam_checks_re);

1;  # ensure a defined return

For Postfix integration, enter the following from a terminal prompt:

root@ubuntu:~# postconf -e ‘content_filter = smtp-amavis:[127.0.0.1]:10024’

Next edit /etc/postfix/master.cf and add the following to the end of the file:

root@ubuntu:~# vi /etc/postfix/master.cf

# Amavis return path
#
127.0.0.1:10025 inet n    -       n       -       -     smtpd
        -o content_filter=
        -o smtpd_authorized_xforward_hosts=127.0.0.0/8
        -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
        -o local_header_rewrite_clients=

smtp-amavis     unix    -       -       -       -       1       smtp
        -o smtp_data_done_timeout=1200
        -o smtp_send_xforward_command=yes
        -o disable_dns_lookups=yes
        -o max_use=20

root@ubuntu:~# vi /etc/spamassassin/local.cf

## Pyzor
#use_pyzor       1
#pyzor_path      /usr/bin/pyzor
ifplugin Mail::SpamAssassin::Plugin::Pyzor
  use_pyzor       1
  pyzor_path /usr/local/bin/pyzor
  pyzor_options --homedir /etc/mail/spamassassin/.pyzor
endif

Restart all the services:
root@ubuntu:~# systemctl start spamassassin.service
root@ubuntu:~# systemctl restart amavis.service
root@ubuntu:~# systemctl restart postfix.service
root@ubuntu:~# systemctl restart dovecot.service

Make a test:
root@ubuntu:~# echo “test” | spamassassin -D pyzor 2>&1 | less

Check by from websites:
https://www.mail-tester.com/
or
https://www.unlocktheinbox.com/mail-tester/