freebsd-ports/mail/postfix23/pkg-message

If you have postfix configured in your /etc/mail/mailer.conf (answered yes to
the previous question) and would like to enable postfix to start at boot time,
please set these variables in your /etc/rc.conf file:

sendmail_enable="YES"
sendmail_flags="-bd"
sendmail_outbound_enable="NO"
sendmail_submit_enable="NO"
sendmail_msp_queue_enable="NO"

This will disable Sendmail completely.

Alternatively to the above settings, you can enable postfix to start with
the other local services, for example, after your database server starts if
you need it to be running for postfix.  To do this, set in your rc.conf file:

sendmail_enable="NONE"                                

Then make the following symbolic link:

cd /usr/local/etc/rc.d
ln -s /usr/local/sbin/postfix postfix.sh


Also, you will want to disable some Sendmail-specific daily maintenance
routines in your /etc/periodic.conf file:

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 /usr/local/etc/sasldb* file(s) readable by group mail (this should
be the default for new installs).

If you are upgrading from postfix version prior to 2.0, please see the README
files for recommended changes to your configuration.