Mois : mars 2018

The bus topology is a LAN where computers are interlinked with an unique straight line. But if the cable does not work any more, the LAN it is paralyzed. And do no longer exists. The hosts share a mutual cable, But it also allows the transfer of data, the flow is reduced. And if two computers communicate at the same time the communication will be interrupted.


The star topology, is a LAN where computers are interlinked with a hub or a switch. It is more efficient than a bus topology,  because it is less sensitive and doesn’t paralyze the network. But it is more expensive.

Chloé

What is a local network ?

A local network, usually designated by the acronym LAN (Local Area Network) is the fact of connecting informatic equipments placed in a same area, to be able to communicate and share an internet connection through a router.

A local network is a closed network accessible only by those who are connected to the switch. The equipments are connected between themselves and they can also be linked to an external network.

How to create a local network ?

To create a local network on Windows is closely linked to the « Center Network and Sharing » of the system. Through this we can define the common resources to share and configure the different permissions to get.  In summary, the « Center Network and Sharing » serves to configure the management of the network.

XXXXXXXXXXXXXXXXXXXXXXX

To create a local network, it’s necessary to supply the following equipment:

-A network card

-A hub Ethernet (this device is essential to put two computers in sharing Windows)

To begin, be careful to the connected connectors

After that, here is to configure the IP addresses.

Each peripheral on the network has an IP address. For a domestic network, it is more practical to leave the system managing this appearence with the option DHCP(the system put an IP address automatically). But to avoid errors of sharing or some access problems, here it is better to fix its Ip addresses.

If an IP address is in the format XXX.XXX.XXX.XXX with each number between 1 and 255, we have addresses like 190.172.40.15.

To link several peripherals at the same group, it is enough to give for each IP address the same 3 first numbers and change only the last one.

Benoît

Thanks to a lot of technical means computing security will prevent unauthorized and inappropriate use, modification and misappropriation. The computer security protects the data and the systems of the information system.

The information system can collect, stock, process and distribute information thanks to a computer.

The goals of the information system security are :

• Availability
• Integrity
• Confidentiality

Tommy

Arduino is a programmable open source hardware and software interface, it allows free access to a certain type of files. It is based on programming language such as type « C ». For programming, the « JAVA’s » language is used.

The arduino card can be used to program various objects, such as alarms, oscilloscopes and everyday objects. Arduino shields can be used to extend the map’s features, such as a GPS, or WI-FI and protect the Arduino card.

Arduino Card

 

Shield

 

 

Enzo et Xavier

How to secure your Wifi network?

Here are the 5 points to secure Wi-Fi that I will detail later:

1. Encrypt your Wi-Fi network

2. Change the default password of the box

3. Update the box

4. Make MAC filtering

5. Change the network name

 

1. Encrypt your Wi-Fi network

We have seen that with a Wi-Fi network, any data sent or received can be intercepted by anyone with the necessary tools. Network sniffers are used to read the plaintext contents of messages that pass through. These messages can be passwords and other confidential informations.

2. Change the default password of the box

If you need to give a username and password to enter the control panel (at Free you must first login via your subscriber account), check to have chosen a complicated password and especially not the default one. Some ISPs may send the default password by email or mail.

It is a password that must be changed like any other default password. Some access credentials to modem administration are sometimes extremely obvious and known to all. Indeed, some sites list the default credentials of most providers.

3. Update your box

Access providers may provide software updates. These are updates that may be related to modem security. They are therefore to be taken seriously and to be done as soon as possible. For recent modems, updates should be automatic.

4. Make MAC filtering

A Mac address is an address stored in a network adapter that is unique to the world. Mac address filtering is therefore to tell your modem that only people whose network card contains the Mac address in question are allowed to connect.

There are advantages and disadvantages: Security is assured in the sense that you decide who is accessing the network for good, but you will need to add Mac addresses each time you change network cards or add devices to the Wi-Fi network.

5. Change the network name

While this only plays a small role in the security of the Wi-Fi network itself, changing the default network name (SSID) is a way to tell potential hackers that you take your security seriously. There is less chance of attacking someone who seems to know about a person who appears to be new to a default network name.

Mathias

 

 

Before starting you need to check a few steps.

• Step 1 : The welder’s battery need to be charged at +20% & the working surface and the tools must be clean. Prepare the optical fiber.

• Step 2 :  Denude the white sheath of the optical cable.

-Cut the Kevlar.

• Step 3 : Remove the jacket on 15 cm.

• Step 4 : Clean all the optical fibers with an alcohol wipe.

The cable contains 4 fibers. Select just one fiber.

• Step 5 : Put a thermo-retractable sleeve named « smoove », uniquely on one fiber to weld.

 

• Step 6 : Remove the buffer on 3 cm.

 

• Step 7 : Clean the optical fiber with an alcohol wipe.

 

• Step 8 : Cut very cleanly the end of the optical fiber with the cleaver.

Joining by fusion the optical fibers.

• Step 9 : Put the two fibers in the welder, the « smoove » staying at the outside.

 

• Step 10 : Preview the welder’s screen.

 

• Step 11 : Wait the end of the tension test, then raise the welder’s protective cover.

 

• Step 12 : Remove the welded fiber and slide the « smoove ».

 

• Final step : Put the fiber in the oven, to the back of the welder. After doing that, the fiber can cool on the support located on the welder’s handle.

 

Albane & Enzo.

Phishing, what is it?

It can be unsolicited advertising, which is also called « spam ».It can also be attempts to scam emails or text messages. In this case their author will try to recover money by various means or incite you to open a file containing a computer virus.

How to avoid and identify this type of scam? 

The most common practices are referred to as « scam » or « phishing ». A stranger sends you an email to offer you to act as an intermediary against remuneration for a financial transaction or to recover your winnings from a lottery or to contact him to collect an inheritance. You are asked to provide your contact information then you will be asked to pay any fees without you getting anything back. If you have received spam on your email or if the message appears to be a phishing attempt, do not reply and do not open the attachments!

Lorenzo