Instant Messaging (IM) Service (Jabber/XMPP)

Instant messaging (IM) applications manage a list of people with whom one wishes to stay in touch by exchanging messages. They convert the asynchronous communication provided by email in a synchronous communication in which participants can communicate in real time.

Besides the basic conversation, IM has other benefits such as:

• Chat rooms.
• File transfer.
• Status updates (e.g.: you are busy, on the phone, away or idle).
• Shared whiteboard to view and show drawings with contacts.
• Simultaneous connection from devices with different priorities (e.g.: from the mobile and the computer, giving preference to one of them for receiving messages).

Nowadays, there are many instant messaging protocols such as ICQ, AIM, MSN or Yahoo! Messenger, whose operation is essentially privative and centralized.

However, Jabber/XMPP is a set of protocols and technologies that enable the development of distributed messaging. These protocols are public, open, flexible, extensible, distributed and secure. Moreover, although Jabber/XMPP is still in the process of becoming an international standard, it has been adopted by Cisco or Google (for its messaging service Google Talk) among others.

eBox employs Jabber/XMPP as its IM protocol integrating users with Jabber accounts. jabberd2 [1] XMPP server is being used for eBox Jabber/XMPP service.

[1]	jabberd2 - XMPP server <http://jabberd2.xiaoka.com/>.

Configuring a Jabber/XMPP server with eBox

To configure the Jabber/XMPP server in eBox, first check in Module Status if the Users and Groups module is enabled, as Jabber depends on it. Then, mark the Jabber checkbox to enable the Jabber/XMPP eBox module.

Jabber General Configuration

To configure the service, go to Jabber in the left menu, setting the following parameters:

Domain Name:

Specifying the domain name of the server. User accounts will be user@domain.

Tip

domain should have an entry in the DNS server, so it can be resolved from the clients.

Connect to other servers:

To allow our users contact users in external servers, and the other way around, check this box. Otherwise, if you want a private server for your internal network, it should be left unchecked.

Enable Multi User Chat (MUC):

Enables conference rooms (chat for more than two users).

Tip

the conference rooms are under the domain conference.domain which like the Domain Name should have an entry in the DNS server, so it can be resolved from the clients too.

SSL Support:

It specifies whether the communications (authentication and chat messages) with the server are encrypted or plaintext. You can disable it, make it mandatory or leave it as optional. If you set it as optional, this setting will be selected from the Jabber client.

To create a Jabber/XMPP user account, go to Users ‣ Add User if you want to create a new user account, or to Users ‣ Edit User if you just want to enable the Jabber account for an already existing user account.

Setting up a Jabber account

As you can see, a section called Jabber Account will appear, where you can select whether the account is enabled or disabled. Moreover, you can specify whether the user will have administrator privileges. Administrator privileges allow to see which users are connected to the server, send them messages, set the message displayed when connecting (MOTD, Message Of The Day) and send a notice to all users connected (broadcast).

Setting up a Jabber client

To illustrate the configuration of a Jabber client, we will use Pidgin and Psi, but if you use another client, the next steps should be very similar.

Pidgin

Pidgin [2] is a multi-protocol client that allows to manage multiple accounts at the same time. In addition to Jabber/XMPP, Pidgin supports many other protocols such as IRC, ICQ, AIM, MSN and Yahoo!.

[2]	Pidgin, the universal chat client <http://www.pidgin.im/>.

Pidgin was included by default in the Ubuntu desktop edition until Karmic, but still is the most popular IM client. You can find it in the menu Internet ‣ Pidgin Internet Messenger. When starting Pidgin, if you do not have any account configured yet, the window to manage accounts will appear as shown in the picture.

From this window, you can add new accounts, modify and delete existing accounts.

Clicking on Add, two tabs with the basic and advanced configuration will appear.

For the Basic configuration of your Jabber account, start by selecting the protocol XMPP. The Username and Password should be the same that the Jabber enabled user account has on eBox. The Domain must be the same that is set up in the Jabber/XMPP eBox module configuration. Optionally, in the field Local alias, write the name you want to show to your contacts.

On the Advanced tab we can configure the SSL/TLS settings. By default Require SSL/TLS is checked, so if we disabled on eBox the SSL Support we must uncheck this and check Allow plaintext auth over unencrypted streams.

If we didn’t change the default SSL certificate a warning will be raised asking whether we want to accept it.

Psi

Psi [3] is a Jabber/XMPP client that allows to manage multiple accounts at the same time. Fast and lightweight, Psi is fully open-source and compatible with Windows, Linux, and Mac OS X.

[3]	Psi, The Cross-Platform Jabber/XMPP Client For Power Users <http://psi-im.org/>.

When starting Psi, if you do not have any account configured yet, a window will appear asking to use an existing account or registering a new one as shown in the picture. We will select Use existing account.

On the Account tab we will setup the basic configuration like the Jabber ID or JID which is user@domain and the Password. The user and password should be same that the Jabber enabled user account has on eBox. The domain must be the same that is set up in the Jabber/XMPP eBox module configuration.

On the Connection tab we can find the SSL/TLS settings between other advanced configuration. By default Encrypt connection: When available is selected. If we disabled on eBox the SSL Support we must change Allow plaintext authentication to Always.

If we didn’t change the default SSL certificate a warning will be raised asking whether we want to accept it. To avoid this message check Ignore SSL warnings on the Connection tab from last step.

The first time we connect the client will raise a harmless error because we haven’t published our personal information on the server yet.

Optionally we can publish some information about ourselves here.

Once published, this error won’t appear again.

Setting up Jabber MUC (Multi User Chat) rooms

Jabber MUC or Multi User Chat is a service that allows multiple users exchange messages in the context of a room. Features like room topics, invitations, ability to kick and ban users, require password to join a room and many more are available in Jabber MUC rooms. For a full specification of MUC check, XEP-0045: Multi-User Chat [4] draft.

[4]	The Jabber/XMPP chat rooms specification is available in <http://xmpp.org/extensions/xep-0045.html>.

Once we have enabled Enable Multi User Chat (MUC) on the Jabber eBox menu entry, all further room configuration is done from the Jabber clients.

Everybody can create a room on the Jabber/XMPP eBox server and the user who creates a room is the administrator for that room. This administrator can set up all the settings, add other users as moderators or administrators and destroy the room.

One of the settings that we should highlight is Make Room Persistent. By default all the rooms are destroyed shortly after the last participant leaves. These are called dynamic rooms and are the preferred method for multi-user chats. On the other hand, persistent rooms must be destroyed by one of its administrators and are usually setup for work-groups or topics.

On Pidgin to join a chat room go to Buddies –> Join a Chat.... A Join a Chat window will pop up asking for some information like the Room name, the Server which should be conference.domain, the user Handle or nickname and the room Password if needed.

First user in joining a non existent room will lock it and will be asked whether Configure Room or Accept Defaults.

On Room Configuration will be able to set up all the possible settings for the room. This configuration window can be opened later typing /config in the room chat window.

Once configured, other users will be able to join the room under the settings applied, leaving the room unlocked ready to use.

On Psi to join a chat room we should go to General –> Join Groupchat. A Join Groupchat window will pop up asking for some information like the Host which should be conference.domain, the Room name, the user Nickname and the room Password if needed.

First user joining a non existent room will lock it and will be asked to configure it. On the top right corner, a button will show a context menu with the Configure Room option.

On Room Configuration will be able to set up all the possible settings for the room.

Once configured, other users will be able to join the room under the settings applied, leaving the room unlocked ready to use.

Practical example

Enable the Jabber/XMPP service and assign to it a domain name that eBox and the clients are able to resolve.

1. Action: Go to Module Status and enable the module Jabber. When the info about the actions required in the system is displayed, allow them by clicking Accept.

   Effect:

   Enabled the button Save Changes.

2. Action: Add a domain with the desired name and whose IP address is the eBox server one, in the same way done in Practical example B.

   Effect:

   You will be able to use the added domain as the domain for your Jabber/XMPP service.

3. Action: Access the menu Jabber. In the field Domain Name, write the domain name just added. Click Apply Changes.

   Effect:

   Save Changes has been enabled.

4. Action: Save the changes.

   Effect:

   eBox shows the progress while applying the changes. When it finish, a message will be displayed.

   Now the Jabber/XMPP service is ready to be used.