School sysadmin manual
developed with Extremadura schools' network configuration in mind. That
means that the application will work out of the box in those
environments. To use it in other networks, some parameters will be
needed for the application to identify the computers that are part of a
classroom and the users who are real teachers.
Extremadura schools will work without any previous setup because:
- Classroom names follow this format: classroom_name-o01,
classroom_name-o02, ... for the students PC, and classroom_name-pro for
the teacher computer. "Classroom_name" can be any combination of letters and
numbers (although it must begin with a letter). Valid examples are:
classroom1-o01, library-o03, lab1-014, etc.
- Teacher users belong to a unix group called teacher.
Any school following these criteria will be able to begin to use
ControlAula inmediatly without modifying anything. For those schools that do
not, a small setup procedure must be followed, as explained at the
Quick Start Guide
ControlAula config files:
This file is used by the daemon sirvecole
that must be run on every computer in the classroom. It's a normal plain
text file that can only be modified by the root user.
This file can be generated by a graphical frontend using the "Setup
button when ControlAulas is run by a teacher at a teacher computer.
After doing this, it must be copied to every computer in the classroom.
For those who wish to study it or modify it by hand, it contains the following
computer's IP. This must be set for all the computers in the network in
order for the application to work (unless the Extremadura network setup
- ClassroomName is the classroom name for this PC. If the
computer is in
a network where the Extremadura configuration
is not followed, this parameter must be set to the same value on every
computer in the classroom.
- Puertais the IP
address of the gateway to be used by every computer on the network. If
not set, the application will use the result of running the unix
- ipAdmin is an IP address with the same privileges as the
computer. It is intended to facilitate remote access by sysadmins to all the
computers in a school.
- SeApaga will, if set to
"1", shut down a student computer if it has not received a ping response from
the teacher computer within two minutes. In this case, keeping the
teacher computer turned off will prevent the students from turning on their
computers. It can also prevent students from using their computers if they
have unplugged the network cable. This parameter is not active after installing
the application, but after the teacher computer makes first contact with the
student computer, it will be set -- unless it has being previously set to
"0" in this config file. Obviously, this parameter is ignored when the
application is running on a teacher computer.
- MonitorNecesario will,
if set to "1", switch off the student computer if it has not
received a response within two minutes from the ControlAulas application on
the teacher computer. In this case, even if the teacher computer is
on, the students cannot switch on their computers until the teacher
starts the application. The default value for this parameter
is "0". If this parameter is set to "1", the value of SeApaga is
ignored. When the application is running on the teacher computer,
this parameter is also ignored.
is the name of the system group to which the teachers belong. If none is
set, the application will use "teacher"
(when using the application in English). If ControlAula is used in
another language, in translation, the default group name will change (for example, in Spanish it will use "profesor").
To be assigned the priviliges of a teacher, a user must be a member of this group.
- InicioSinInet will,
if set to "1", disable Internet access for the computer.
The default value is "0". If this parameter is set to "1", the computer won't
have an available gateway until the teacher enables Internet access.
- InicioSinRaton will, if set to "1", disable the keyboard and
mouse for the user after login. The default value is "0". If set to "1", the
user won't be able to use the keyboard or mouse until the teacher enables
will, if set to "1", show debugging messages in the TTY in which the
application is started. Its only purpose is making debugging of the
application easier. Its default value is "0".
- SharedPrinter is
used to inform the user whether the teacher has shared ("1") or not ("0") his
or her printer with this PC. This parameter is automatically modified by the
application while running and must not be changed by hand.
is used to inform the user whether the teacher has enabled ("1") or
disabled ("0") Internet access to this PC. This parameter is
automatically modified by the application while running and must not be
changed by hand.
This file stores the classroom setup (desktop distribution, hostnames,
etc.). It's a regular plain text file that can be modified by the teacher
using the "Classroom setup" button in the Application. This file only
needs to be configured on the teacher computer.
For those who wish to study it or modify it by hand, it contains the following
is the number of columns (from 1 to 4) that form the classroom desktop
is the number of rows (from 1 to 10) that form the classroom
is the numerical
position of a desktop within the classroom grid. The
application uses a 40-cell grid beginning with the value 1 for row1,
column1, to the value 40 for row10, column4. This parameter is
repeated in the file with as many lines as there are desktops, using the
format Position/ClassroomName[Desktop No]="x", where x is the number of the
cell representing the desktop on the grid. For example:
Position/room1="3". This parameter should not be modified by hand,
as it's very easy to configure the classroom using the application
- Ocul: flags the desktop as visible or not. This parameter
repeated in the file as many times as there are hidden desktops, and has
the same format as Position; setting this parameter to "1" hides the desktop.
Ocul/room1="1"). This parameter should not be modified by
hand, as it's very easy to configure the classroom using the
- MAC: the MAC address of the computer network card. This
parameter is needed to be able to start the machines via the network
cable. It's automatically assigned the first time controlaula starts and
shouldn't be changed manually.
- Name: the hosntame for every computer in the classroom.
This value will place every computer in the right place in the
classroom distribution. It's assigned using ControlAula as a teacher,
with the "Classroom setup" option: just double click on a desktop
button and rename it.
Several technical issues:
- ControlAulas' source code and future updates are available
at the gnuLinEx
repositories. The development svn repository is available at
- Video broadcasting through the network is done
Sometimes this feature is limited by the network switch configuration. In such
cases the multicast filtering igmp of the switch must be modified.
- Since most of the commercial DVDs these days are encrypted, in order to
broadcast a DVD from the teacher computer, the libdvdcss2 package
must be installed. A Debian package for it can be downloaded from http://ftp.debian-unofficial.org/debian/pool/main/libd/libdvdcss/ and installed using
"dpkg -i package.deb"
(gnuLinEx users can do it automatically
via ControlPanel->Programs->Upgrade LinEx)
- To enable all of the application's functionality, some TCP ports must be open on the computers:
- 41000 is used to interchange information between users using http protocol. It's a must
- 6969 to share files using bittorrent.
- 487 (TCP & UDP) to send files. It uses saft protocol under
inetd, so if ports are closed at the /etc/hosts.deny file it should be
enabled adding" sendfiled:ALL" to the /etc/hosts.allow file.
- 5900 for Big Brother and Projector features. It uses VNC protocol.
- 6522 for the workgroup feature. It uses obby protocol.
Last modification on 18th