To use postfix instead of sendmail:
  - clear sendmail queue and stop the sendmail daemons

Run the following commands to enable postfix during startup:
  - sysrc postfix_enable="YES"
  - sysrc sendmail_enable="NONE"

If postfix is *not* already activated in %%MC_PREFIX%%/etc/mail/mailer.conf
  - mv %%MC_PREFIX%%/etc/mail/mailer.conf %%MC_PREFIX%%/etc/mail/mailer.conf.old
  - install -m 0644 %%DATADIR%%/mailer.conf.postfix %%MC_PREFIX%%/etc/mail/mailer.conf

Disable sendmail(8) specific tasks,
add the following lines to /etc/periodic.conf(.local):
  daily_clean_hoststat_enable="NO"
  daily_status_mail_rejects_enable="NO"
  daily_status_include_submit_mailq="NO"
  daily_submit_queuerun="NO"

If you are using SASL, you need to make sure that postfix has access to read
the sasldb file.  This is accomplished by adding postfix to group mail and
making the %%PREFIX%%/etc/sasldb* file(s) readable by group mail (this should
be the default for new installs).

If you are upgrading from prior postfix version, please see the README
files for recommended changes to your configuration and additional
http://www.postfix.org/COMPATIBILITY_README.html