How to Install Mailman 3 on a Debian 10 Server.

This document is a how to install the Mailman 3 server on a Debian 10 server. The server environment will include Debian 10, NGINX, Let's Encrypt, Postfix, and PosgresDB.

Prepare Server Environment

1. Create a VPS running Debian 10. I recommend something from Digital Ocean or Linode. The server should be a minimum of 1 CPU and 2 Gigabyte of Memory. 25-50 Gb of storage should be sufficient.

2. Log into the server as root.

$ ssh root@your_server_ip

3. Create a New User: mailman

# adduser mailman

You will be asked some questions about this new user when running the above command. Please make sure you use a strong password for mailman as it will be typically known that any server running Mailman 3 will have a mailman user setup on it.

4. Let's go ahead and grant the 'mailman' user SUDO privileges while logged in as root:

# usermod -aG sudo mailman

5. I recommend setting up a basic firewall to tighten up security on this Mailman 3 server. UFW is one that can be installed on a Debian 10 server:

# apt update
# apt install ufw

Once UFW is installed, you need to make sure you allow the various applications that Mailman 3 will be using through UFW. Some of these applications are the following: OpenSSH, Nginx Full, and Postfix.

So here is an example of what to do immediately after you install UFW:

# ufw app list

Output
Available applications:
 . . .
 OpenSSH
 . . .

This tells us what available applications we can configure UFW to allow. So let's add OpenSSH to UFW:

# ufw allow OpenSSH

Now we can enable UFW:

# ufw enable

You can see what is allowed through the UFW firewall by running the following command:

# ufw status

Output
Status: active

To             Action   From
--             ------   ----
OpenSSH          ALLOW    Anywhere
OpenSSH (v6)     ALLOW    Anywhere (v6)