FreeBSD email server - Part 1: Preparations

This tutorial is devised into multiple chapters to make it more manageable, and to be able to better explain why certain parts are needed.

The tutorial is created out of experience setting up my own email server. I have read through quite a lot of documentation so you do not have to. Nonetheless, I would recommend doing so. Email business is a tricky one, with a lot of moving parts that have to fit into each other. Knowing how exactly each part works will greatly help understanding why they are needed in a proper email server. Besides that, it will make your life a lot more enjoyable if you want to tweak some things after this tutorial.

To kick off, some preparations should be done before you start on setting up your own email server.

DNS setup

Some DNS setup is required for mail. Most importantly, the MX records of a domain. Be sure you have a domain available, otherwise, get one. There are plenty of registrars and the price is pretty low for most domains. If you want to look hip, get a .email TLD for your email server.

For the DNS records themselves, make sure you have an A record pointing to the server IP you’re going to use. If you have an IPv6 address, set up an AAAA record as well. Mail uses the MX DNS records. Make one with the value 10 @. If you have multiple servers, you can make MX records for these as well, but replace the 10 with a higher value each time (20, 30, etc). These will be used as fallback, in case the server with pointed to by the 10 record is unavailable.

PostgreSQL

Next up you will have to install and configure PostgreSQL. Although using a database is not required, this tutorial will make use of one. Using a database makes administration easier and allows you to add a pretty basic web interface for this task.

Installation

Since the tutorial uses FreeBSD 11, you can install PostgreSQL easily by running

pkg install postgresql96-server

Starting up

In order to start Postfix, you should enable the system service for it. This way, service can be used to easily manage it. In addition, it will start automatically on boot.

echo 'postgresql_enable="YES"' >> /etc/rc.conf.local
service postgresql start

Database initialization

Since PostgreSQL is a little different than the more popular MySQL, I will guide you through setting up the database as well. To begin, switch user to postgres, which is the default administrative user for PostgreSQL. Then simply open up the PostgreSQL CLI.

su postgres
psql

Once you are logged in to PostgreSQL, create a new user which will hold ownership of the database and make a database for this user.

CREATE USER postfix WITH PASSWORD 'incredibly-secret!';
CREATE DATABASE mail WITH OWNER postfix;

Once this is done, create the tables which will hold some of our configuration data.

domains

CREATE TABLE domains (
    name VARCHAR(255) NOT NULL,
    PRIMARY KEY (name)
);

users

CREATE TABLE users (
    local VARCHAR(64) NOT NULL,
    domain VARCHAR(255) NOT NULL,
    password VARCHAR(128) NOT NULL,
    PRIMARY KEY (local, domain),
    FOREIGN KEY (domain) REFERENCES domains(name) ON DELETE CASCADE
);

aliases

CREATE TABLE aliases (
    domain VARCHAR(255),
    origin VARCHAR(256),
    destination VARCHAR(256),
    PRIMARY KEY (origin, destination),
    FOREIGN KEY (domain) REFERENCES domains(name) ON DELETE CASCADE
);

Let’s Encrypt

Installation

Installing the Let’s Encrypt client is just as straightforward as the PostgreSQL database, using pkg.

pkg install py27-certbot

Getting a certificate

Requesting a certificate requires your DNS entries to properly resolve. If they do not resolve yet, Let’s Encrypt will bother you with errors. If they do resolve correctly, use certbot to get your certificate.

certbot certonly --standalone -d domain.tld

Conclusion

This should be everything required to get started on setting up your own email server. Continue to part 2 of this series to start setting up Postfix.