ejabberd (an XMPP Server)

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Ejabberd is a server for the XMPP protocol written in Erlang. It's easier to configure and setup than Prosody due to having most of its modules built-in and pre-configured by default.

Prerequisites

Subdomains

Ejabberd presumes that you have already created all the required and optional subdomains for its operation prior to running it.

Depending on the usecase, you may need any or all of the following domains for XMPP functionality:

This guide will assume all these subdomains have been created.

Installation

Ejabberd is available in the Debian repositories:

apt install ejabberd

Configuration

The ejabberd server is configured in /etc/ejabberd/ejabberd.yml. Changes are only applied by restarting the ejabberd daemon in systemd:

systemctl restart ejabberd

Hostnames

The XMPP hostname is specified in the hosts section of ejabberd.yml:

hosts:
  - example.org

Certificates

Unlike Prosody, ejabberd doesn't come equipped with a script that can automatically copy over the relevant certificates to a directory where the ejabberd user can read them.

One way of organizing certificates for ejabberd is to have them stored in /etc/ejabberd/certs, with each domain having a separate directory for both the fullchain cert and private key.

Using certbot, this process can be easily automated with this one-liner:

$DOMAIN=subdomain.example.org
certbot --nginx -d $DOMAIN certonly; mkdir /etc/ejabberd/certs/$DOMAIN; cp /etc/letsencrypt/live/$DOMAIN/fullchain.pem /etc/ejabberd/certs/$DOMAIN; cp /etc/letsencrypt/live/$DOMAIN/privkey.pem /etc/ejabberd/certs/$DOMAIN

This should be ran with your XMPP hostname (example.org) and repeated for all your desired subdomains.

To enable the use of all these certificates in ejabberd, the following configuration is necessary:

certfiles:
  - "/etc/ejabberd/certs/*/*.pem"

Admin User

The admin user can be specified in ejabberd.yml under the acl section:

acl:
  admin:
    user: admin

This would make admin@example.org the user with administrator privileges.

Message Archives

The ejabberd server supports keeping archives of messages through its mod_mam module. This can be enabled by uncommenting the following lines:

mod_mam:
  assume_mam_usage: true
  default: always

Database

Why use a database?

In the mod_mam section of the ejabberd config file, the following message is in comments:

mod_mam:
  ## Mnesia is limited to 2GB, better to use an SQL backend
  ## For small servers SQLite is a good fit and is very easy
  ## to configure. Uncomment this when you have SQL configured:
  ## db_type: sql

As these comments imply, an SQL backend is strongly recommended if you wish to use your ejabberd server for anything more than just testing. Ejabberd supports MySQL, SQLite and PostgreSQL.

While all of those are suitable choices, the best database system to use is PostgreSQL. It's the same database backend used by PeerTube and Matrix, making it the most convenient option if you're already running those too.

Installing PostgreSQL

PostgreSQL is available in the Debian repositories:

apt install postgresql

Start the PostgreSQL daemon to begin using it:

systemctl start postgresql

Creating the Database

To create the database, first create a PostgreSQL user for ejabberd:

su -c "createuser --pwprompt ejabberd" postgres

Then, create the database and make ejabberd its owner:

su -c "psql -c 'CREATE DATABASE ejabberd OWNER ejabberd;'" postgres

Importing Database Scheme

Ejabberd doesn't create the database scheme by default; It has to be imported into the database before use.

su -c "curl -s https://raw.githubusercontent.com/processone/ejabberd/master/sql/pg.sql | psql ejabberd" postgres

Configuring ejabberd to use PostgreSQL

Finally, add the following configuration to ejabberd.yml:

sql_type: pgsql
sql_server: "localhost"
sql_database: "ejabberd"
sql_username: "ejabberd"
sql_password: "psql_password"

Once you've ensured your database name, username and password are all correct, enable SQL storage for mod_mam:

mod_mam:
  ## (Other parameters)
  db_type: sql

Using ejabberd

Registering the Admin User

To begin using ejabberd, firstly start the ejabberd daemon:

systemctl restart ejabberd

Then, using ejabberdctl as the ejabberd user, register the admin user which is set in ejabberd.yml:

su -c "ejabberdctl register admin example.org password" ejabberd

This will create the user admin@example.org.

Using the Web Interface

By default, ejabberd has a web interface accessible from http://example.org:5280/admin. When accessing this interface, you will be prompted for the admin credentials:

After signing in with the admin credentials, you will be able to manage your ejabberd server from this web interface:

TURN & STUN for Calls

Ejabberd supports the TURN and STUN protocols to allow internet users behind NATs to perform voice and video calls with other XMPP users.

Firstly, setup a TURN and STUN server with Coturn, using an authentication secret.

Then, edit mod_stun_disco to contain the appropriate information for your turnserver:

  mod_stun_disco:
    secret: "your_auth_secret"
    services:
      -
	host: turn.example.org
        type: stun
      -
	host: turn.example.org
	type: turn

And with that, you've successfully setup your ejabberd XMPP server!


Written by Denshi. Donate Monero here [QR]