Chat Server
Implementation using Jabber and IM Clients Installation
What is jabber ?
Jabber
1. Rapid and indistinct speech
2. To talk in a noisy, excited, or declamatory manner
3. A streaming XML technology mainly used for instant messaging
Jabber is best known as "the Linux of instant messaging" -- an
open, secure, ad-free alternative to consumer IM services like
AIM, ICQ, MSN, and Yahoo (see the IM quickstart). Under the
hood, Jabber is a set of streaming XML protocols and
technologies that enable any two entities on the Internet to
exchange messages, presence, and other structured information in
close to real time. Jabber technologies offer several key
advantages:
Open -- the Jabber protocols are
free, open, public, and easily understandable; in addition,
multiple implementations exist for clients, servers, components,
and code libraries.
Standard -- the Internet
Engineering Task Force (IETF) has formalized the core XML
streaming protocols as an approved instant messaging and
presence technology under the name of XMPP, and the XMPP
specifications have been published as RFC 3920 and RFC 3921.
Proven -- the first Jabber
technologies were developed by Jeremie Miller in 1998 and are
now quite stable; hundreds of developers are working on Jabber
technologies, there are tens of thousands of Jabber servers
running on the Internet today, and millions of people use Jabber
for IM.
Decentralized -- the architecture
of the Jabber network is similar to email; as a result, anyone
can run their own Jabber server, enabling individuals and
organizations to take control of their IM experience.
Secure -- any Jabber server may be
isolated from the public Jabber network (e.g., on a company
intranet), and robust security using SASL and TLS has been built
into the core XMPP specifications.
Extensible -- using the power of
XML namespaces, anyone can build custom functionality on top of
the core protocols; to maintain interoperability, common
extensions are managed by the Jabber Software Foundation.
Flexible -- Jabber applications
beyond IM include network management, content syndication,
collaboration tools, file sharing, gaming, and remote systems
monitoring.
Diverse -- a wide range of
companies and open-source projects use the Jabber protocols to
build and deploy real-time applications and services; you will
never get "locked in" when you use Jabber technologies.
Download Jabber
Server
http://www.jabber.org/software/servers.shtml
Client
http://www.jabber.org/software/clients.shtml
Jabber Documentation
http://www.jabber.org/user/userguide/
Jabber FAQ
http://www.jabber.org/user/userfaq.shtml
Installing Jabber in
Debian
#apt-get install jabber
This will download and install jabber, jabber-common and any
other packages your system might need. The server will be
started automatically at this point, so we need to stop it and
update the configuration to work with your host. To stop the
server run
# /etc/init.d/jabber stop
Now we can look at the configuration files inside the directory
/etc/jabber. The main thing that we need to setup is the
hostname directive. The server itself is primarily configured
via the XML file /etc/jabber/jabber.xml, but as a convience the
startup script of the Debian package will make use of the file
jabber.cfg as well, and this is where we'll set the name up. In
a small office where you have your own DNS system it is useful
to setup a hostname to refer to the system, this allows you to
move machines without having to change any clients. We've used
chat.my.company before for this purpse. In this case We are just
using the hostname of the current machine. So edit the file
/etc/jabber/jabber.cfg to have your hostname
JABBER_HOSTNAME (which is then passed to jabberd in the -h
switch)
JABBER_HOSTNAME=chatserver.my.flat
Now we can start the server up
# /etc/init.d/jabber start
Starting jabberd: jabberd.
Connecting to the server involves downloading and installing a
chat client.Client is gabber for Linux, and Exodus for Windows.
Other clients exist packaged for Debian including PSI. To
install gabber, on a client machine, run
#apt-get install gabber
Then once it's installed you will be shown a connection dialog.
This has space for a username, a password, and a server name.
Enter the username and password you wish to use and the name of
the server you already setup. (In my case thats
undecided.my.flat). Once you click the connect button you will
see the following error message
Gabber could not log you in.
Would you like Gabber to try to create a new
account on the selected Jabber server?
Click 'Yes' and your account will be created. You will then see
the main contact window which should show that you have received
a new message from the server saying 'Welcome'. If you now move
to another machine you can repeat the process to add another
user. Finally you can add the users to each others contact list,
called a roster in Jabber-speak. Click on the Actions menu and
select Add Contact. Then choose Add this JabberID. Type in the
ID of the user you wish to add in, remembering to add the
hostname. For example
debianhelp@chatserver.my.flat
All Jabber contacts have the form username@hostname - just like
an email address, even though it isnt! Once the other person
logs in and approves the addition you will be able to chat to
them! The roster lists are all maintained upon the server side,
in a directory beneath /var/lib/jabber named after the servers
hostname. If you examine one of the ones you've created already
you will see there is a section at the start for the username
and password and some global options and then at the end there
is a section at the end for the contacts. With a bit of
scripting you can generate these files for all your users
yourself and add each other to their groups.
Jabber Transports (MSN, Yahoo, ICQ etc)
Jabber Clients Installation
#aptitude search jabber
will show you what is available. I'm going to go through
jabber-msn (MSN), jabber-jit (ICQ) and jabber-yahoo (Yahoo).
Let's install them
#aptitude install jabber-jit jabber-msn jabber-yahoo
Now - we need to configure and enable them.
Hostnames
For the transports to work - you need to set hostnames - and -
if you are running the server non-locally then you need to have
resolvable hostnames.
We chose the following scheme:
jabber.mydomain.tld
msn.jabber.mydomain.tld
conf.msn.jabber.mydomain.tld
icq.jabber.mydomain.tld
yahoo.jabber.mydomain.tld
All of these are CNAMES to the same machine. I am not sure if
they require to have different hostnames - but the examples seem
to suggest this.
Configuration
You need to configure so that the jabber server knows about the
transports and also so that the transports will announce
themselves to the jabber client.
In the debian package config /etc/jabber/jabber.xml find the
section.
Here we add the browse config (these are taken from the /usr/share/doc/jabber-*/README.Debian
files - the only change was the hostname in each case).
<service type="yahoo" jid="yahoo.jabber.mydomain.tld"
name="Yahoo! Transport">
<ns>jabber:iq:gateway</ns>
<ns>jabber:iq:register</ns>
</service>
<service type="msn" jid="msn.jabber.mydomain.tld" name="MSN
Link">
<ns>jabber:iq:gateway</ns>
<ns>jabber:iq:register</ns>
</service>
<service type="icq" jid="icq.jabber.mydomain.tld" name="ICQ
Link">
<ns>jabber:iq:gateway</ns>
<ns>jabber:iq:register</ns>
<ns>jabber:iq:search</ns>
</service>
Next we need to add the actual services - add the following new
service sections (again taken from /usr/share/doc)
<service id="msn">
<host>msn.jabber.mydomain.tld</host>
<host>conf.msn.jabber.mydomain.tld</host>
<accept>
<ip>your_ip</ip>
<port>5557</port>
<secret>asecret</secret>
<timeout>30</timeout>
</accept>
</service>
<service id="yahoo.jabber.mydomain.tld">
<accept>
<ip>your_ip</ip>
<port>9001</port>
<secret>asecret</secret>
</accept>
</service>
<service id="icq">
<host>icq.jabber.mydomain.tld</host>
<host>sms.icq.jabber.mydomain.tld</host>
<accept>
<ip>your_ip</ip>
<port>5555</port>
<secret>asecret</secret>
<timeout>30</timeout>
</accept>
</service>
Finally we need to edit the transport config files
(/etc/jabber/jabber-*.xml). Here you need to make sure that the
following is done
make sure that the is the same as set in the main config
Enabling
In /etc/default/ you will find jabber-* files. The value ENABLED
must be changed from 0 to 1
Using
Given that you have a jabber account on the jabber server we can
now add buddies via the transports.
You need to use your jabber client to run services discovery on
the server. That should show the transports that are available
(amongst any other allowed services).
Choose a transport and then register. You can then fill out your
account details for that chat system.
It should then find any buddies (most of these IMs have server
stored buddy lists) - but - when manually adding buddies the
syntax is
ICQ user has an ID of UIN: UIN@icq.jabber.mydomain.tld
MSN: user has an ID of user@host.tld: user%host.tld@msn.jabber.mydomain.tld
Yahoo: user has an ID of YahooID: YahooID@yahoo.jabber.mydomain.tld
