Postfix

Postfix is a sendmail server. You can use it to send mail.
You may also be interested in dovecot (mail server - receive).

Documentation

official docs	http://www.postfix.org/documentation.html
All Commands	http://www.postfix.org/OVERVIEW.html

Locations

/usr/local/etc/postfix/main.cf	Primary Postfix Config
/var/log/maillog	FreeBSD mail log

Supplementary Docs

Textbooks

O'Reilly Definitive guide to postfix

See calibre

Tutorials

send-only SMTP server	https://sbcode.net/prometheus/smtp-server/
Simple Dovecot/Postfix Server Instructions	https://www.vultr.com/docs/simple-mailserver-postfix-dovecot-sieve-freebsd-10
FreeBSD Postfix Setup	http://www.area536.com/projects/complete-freebsd-mail-server/postfix-youve-got-incoming/
ArchWiki postfix/dovecot/roundcube	https://wiki.archlinux.org/title/Virtual_user_mail_system_with_Postfix,_Dovecot_and_Roundcube

Notes

postfix install

postfix configuration

postfix configurations

postfix usage