postfix.txt

> pull stuff from the wiki in here

# Ok this is going to be RANDOM since I'm writing as I read docs. It might be mostly accurate.

# === CRASHCOURSE WHAT EVEN IS EMAIL AGAIN ===
# Postfix is not a mailserver, it's an MTA, it speaks SMTP, like sendmail and Exim.
# Mailservers (like Dovecot) speak POP3 and IMAP and deal with user accounts (and of course talk
#   to MTAs).
# Postfix is meant to replace sendmail.
# In general, Postfix deals with mails that need to be sent (from a client), mailservers deal
# with mail that has been received and will be fetched/read (by a client).
# === END ===

# for systemd boxes it'll run as postfix.service


# === DOCUMENTATION ===
# it doesn't have "a readme", it has directories of them, find them here (if not online):
$ postconf readme_directory html_directory
# if that returns errors, just find them in All the settings:
$ postconf | grep -e readme -e html

# You want to scan at least the BASIC_CONFIGURATION_README. This file has an introduction, which
#   gives a brief description of the chapters in the rest of the file, which are shown as:
# "    * Postfix configuration files"
# and show up in bold after the introduction. In the browser version they're links:
https://www.postfix.org/BASIC_CONFIGURATION_README.html


# === OPTIONS ===
# Config files are in /etc/postfix, the two important ones are main.cf and master.cf
# Parameters are set like shell variables, except
#  1. postfix doesn't know about quotes, and
#  2. you can use variables before you set them:
   other_parameter = $parameter
   parameter = value

# Postfix has a _metric fuckton_ of options (the one I'm looking at has over 800):
$ postconf | less
# you can scan that for whatever thing you want to check, change and/or break

# show the settings currently in main.cf
$ postconf -n

# after changing things:
$ postfix reload


# See also: mail (useful for testing!)