[Tutorial] Set up a federated XMPP Chat Network with ejabberd, your own Google Talk...

Raymii

This tutorial shows you how to set up your own federated chat network using ejabberd. It covers a basic single node ejabberd server and also the setup of an ejabberd cluster, including errors and DNS SRV record examples. Last but not least federation is also covered. You can use an Inception Hosting VPS to set up your own XMPP server, I use them and they are very stable and offer good performace and pricing.

Why set up your own XMPP server

There are a few reasons to set up your own XMPP server.

You might use Google Talk or as it now is named Hangouts. Google's service recently changed and it is going to drop XMPP compatibility. If you have non-gmail chat contacts you can keep chatting to them. And still use an open protocol which is widely supported, not being locked in to google specific software and hardware.

Or you might want to have more control over the logging of your data. Turn of ejabberd logging and use Off The Record which gives you full privacy (and perfect forward secrecy).

You might want to use awesome multi-account chatting applications like Pidgin, Psi+, Empathy, Adium, iChat/Messages or Miranda IM. And on Android you can use Xabber, Beem or OneTeam. Did you know that big players like Facebook, WhatsApp and Google (used) to use XMPP as their pimary chat protocol?

Or you might be a sysadmin in need of an internal chat solution. I've got a ejabberd cluster running for a client consisting of 4 Debian 7 VM's (2GB RAM each) spread over 3 sites and 1 datacenter, serving 12000 total users and most of the time 6000 concurrently.

XMPP is an awesome and extendible protocol, on which you can find more here: https://en.wikipedia.org/wiki/XMPP

Information

This setup is tested on Debian 7, Ubuntu 12.04 and 10.04 and OS X 10.8 Server, all running ejabberd installed via the package manager, either apt or ports. It also works on Windows Server 2012 with the ejabberd compiled from the erlang source but that is not covered in this tutorial.

This tutorial uses the example.org domain as the chat domain, and the server chat.example.org as the xmpp server domain. For the clustering part the servers srv1.example.org and srv2.example.org are used. Replace these values for your setup.

Single node / master node ejabberd installation

If you want to set up a single node installation of ejabberd, e.g. no clustering, then follow only this part and the DNS part of the tutorial. If you want to set up a cluster, then also follow this part and continue with the next part.

Installing Ejabberd

This is simple, use your package manager to install ejabberd:

apt-get install ejabberd

You will also install a few dependencies for the erlang runtime.

Configuring ejabberd

We are going to configure the ejabberd service. First stop it:

/etc/init.d/ejabberd stop

Now use your favorite text editor to edit the config files. The ejabberd config is erlang config, so comments are not # but %%. Also, every config option ends with a dot (.).

vim /etc/ejabberd/ejabberd.cfg

First we are going to add our chat domain name:

{hosts, ["example.org"]}.

If you want more domains then you add them as shown below:

{hosts, ["sparklingclouds.nl", "raymii.org", "sparklingnetwork.nl"]}.

This domain name is not the name of the servers you are adding.

Next we define an admin user:

{acl, admin, {user, "remy", "example.org"}}.

remy corresponds with the part before the @ in the XMPP ID, and example.org with the part after. If you need more admin users, add another ACL line.

Now if you want people to be able to register via their XMPP client enable in band registration:

{access, register, [{allow, all}]}.

If you are using MySQL or LDAP authentication then you wouldn't enable this.

I like to have a shared roster with roster groups, and some clients of mine use a shared roster with everybody so that nobody has to add contacts but they see all online users, enable the mod_shared_roster:

%% Do this in the modules block
  {mod_shared_roster,[]},

If you are pleased with the config file, save it and restart ejabberd:

/etc/init.d/ejabberd restart

We now need to register a user to test our setup. If you've enabled in-band registration you can use your XMPP client, and if you did not enable in-band registration you can use the ejabberdctl command:

ejabberdctl register remy example.org 'passw0rd'

Now test it using an XMPP client like Pidgin, Psi+ or Empathy. If you can connect, then you can continue with the tutorial. If you cannot connect, check your ejabberd logs, firewall setting and such to troubleshoot it.

Clustering ejabberd

The next part of this tutorial can be found over at my website: https://raymii.org/s/tutorials/Set_up_a_federated_XMPP_Chat_Network_with_ejabberd.html - It covers the clustering of ejabberd, troubleshooting and the DNS setup to make federation work.