Title: Configuring an XMPP server for secure, mobile instant messaging
Date: 2017-2-10
Category: xmpp
Tags: xmpp, chat, guide, instant messaging, prosody
Slug: configuring-a-modern-xmpp-server
status: draft

This is a guide to set up a modern XMPP server focused on security and mobile messaging. The whole guide further assumes one is using Debian as a server and that you will end up hosting a few of your friends. It further assumes you have some basic skills working on a linux command line.

To make your server communicate make sure following ports are open in your firewall:

    :::console
    5222 (for client to server)
    5269 (server to server)
    5280 (default http port for prosody)
    5281 (default https port for prosody)


Enabling HTTPS
---

First we acquire a signed HTTPS-certificate via Let's Encrypt:
This is among others required for Gajim plugins to work properly; self-generated certs will not work.

Install Certbot and get new certificates for your domain (replace myserver.org with your own):

    :::console
    wget https://dl.eff.org/certbot-auto
    chmod a+x certbot-auto
    certbot-auto certonly -d muc.placeholderdomain.org -d dump.placeholderdomain.org -d placeholderdomain.org-d placeholderdomain.org

Should you succeed, you will be able to read something like:

    :::console 
    Congratulations! Your certificate and chain have been saved at
    /etc/letsencrypt/live/placeholderdomain.org/fullchain.pem. Your cert will           
    expire on 2017-02-13. To obtain a new or tweaked version of this       
    certificate in the future, simply run certbot-auto again. To                       
    non-interactively renew *all* of your certificates, run                               
    "certbot-auto renew" 

Take note of the path where the certificate is stored as we will use it later.

Installing and setting up MySQL as a storage back-end
---

First update your repositories and install MySQL

    :::console
    apt-get update && apt-get install mysql-server

Run mysql as the root user:

    :::console
    mysql -u root -p

In mysql:

    :::console
    mysql> create database prosody;
    mysql> show databases;

Result should  be something like:

    :::console
    +--------------------+
    | Database           |
    +--------------------+
    | information_schema |
    | mysql              |
    | performance_schema |
    | prosody            |
    +--------------------+

    4 rows in set (0.00 sec)

Create a database account for prosody

    :::console
    mysql> create user prosody;

Give the user prosody the rights to access the database, make sure to change the password and take note of it

    :::console
    mysql> grant all on prosody.* to 'prosody'@'localhost' identified by 'userPassword';

Exit mysql:

    :::console
    exit;

Installing and configuring Prosody, the XMPP server
---
   
Install the newest version of Prosody and its dependencies from the official prosody repository:

    :::console
    echo "deb http://packages.prosody.im/debian wheezy main" >> /etc/apt/sources.list

    wget https://prosody.im/files/prosody-debian-packages.key -O- | sudo apt-key add -

    apt-get install prosody lua-dbi-mysql lua-zlib

Add the Let's Encrypt Certificates to Prosody and make sure Prosody can use them

    :::console
    cp /etc/letsencrypt/live/myserver.org/*.pem /etc/prosody/certs/

Make sure the certificates are owned by prosody and legible only by root:

    :::console
    chown -R prosody:prosody /etc/prosody/
    chmod -R 700 /etc/prosody/certs/

Install the newest prosody plugins:

    :::console
    apt-get install mercurial
    cd /usr/src
    hg clone https://hg.prosody.im/prosody-modules/ prosody-modules

Make a backup of the default prosody configuration and install [the one by the homebrewserver.club]({filename}/downloads/prosody.cfg.lua)

    :::console
    cd /etc/prosody
    cp prosody.cfg.lua prosody.cfg.lua.original
    wget http://homebrewserver.club/downloads/prosody.cfg.lua

Replace all instances of the placeholder domain name and passwords in the config file with your own:

    :::console
    sed -i 's/placeholderdomain.org/yourdomain.net/g' prosody.cfg.lua  && sed -i 's/userPassword/yourownpassword/g' prosody.cfg.lua

Alternatively you can change them by hand. They are on line 61, 69, 72, 75 of prosody.cfg.lua

Finishing up
---

After you've set up all of the above it is time to start the server:

    :::console
    /etc/init.d/prosody restart

Users can be added from the command line, you will also be prompted for a password:

    :::console
    prosodyctl adduser me@placeholderdomain.org
 
Alternatively you can change "allow_registration = false;" to "allow_registration = true;" in the config (line 35) to allow users to register accounts on your server via their clients.

Now you can try connecting to your own server by using a client like Gajim or Conversations. Login with the above configured username and password.

If you have questions about Prosody, the project's [documentation](http://prosody.im/doc) is quite good. If you can't find answers there, try contacting prosody developers and users directly via [the Prosody XMPP chatroom](xmpp://prosody.conference.prosody.im?join)

This guide is a companion to our article [Have You Considered The Alternative?](http://homebrewserver.club/have-you-considered-the-alternative.html) on instant messaging. Also check out our guide on [XMPP clients](http://homebrewserver.club/404).