Postfix SPF Intergration

Intergrate Postfix and SPF to detect email spoofing/forgery.
It enables mail receivers to reject mail that does not come from authorized sources.

1. Install postfix-policyd-spf-python.

sudo apt-get install postfix-policyd-spf-python

2. Add below to /etc/postfix/main.cf.

policyd-spf_time_limit = 3600
smtpd_recipient_restrictions =
   permit_mynetworks,
   permit_sasl_authenticated,
   defer_unauth_destination,
   check_policy_service unix:private/policyd-spf

3. Add below to /etc/postfix/master.cf.

policyd-spf  unix  -       n       n       -       0       spawn
    user=policyd-spf argv=/usr/bin/policyd-spf

4. Restart postfix services.

sudo systemctl restart postfix

5. Monitor postfix log.