REPUBLIQUE DU CAMEROUN

REPUBLIQUE OF CAMEROUN
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....... Paix – Travail - Patrie
Peace – Work - Fatherland
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MINISTERE DE L’ENSEIGNEMENT
MINISTRY OF HIGHER EDUCATION
SUPERIEUR
HIGHER INSTITUTE OF ADVANCED
INSTITUT SUPERIEUR DE TECHNOLOGY
TECHNOLOGY AND MANAGEMENT
ADVANCEE ET DE MANAGEMENT

School: ISTAMA
Department: Computer Engineering
Level: BTECH
Specialty: NACS
Course: TUTORALS OF NETWORKING
Lecturer: Eng. Besong Micheal E.
Work theme: ADHOC NETWORK, WIRELESS
NETWORK SECURITY

Work presented by:

KANA DONJIO MADIO EDITH ESPERANCE
ADHOC NETWORK

DEFINITION

An Ad Hoc network is a temporary Local area network. An ad hoc network is a

network that is composed of individual devices communicating with each other
directly. The term implies spontaneous or impromptu construction because these
networks often bypass the gatekeeping hardware or central access point such as a
router. Many ad hoc networks are local area networks where computers or other
devices are enabled to send data directly to one another rather than going through a
centralized access point. Ad hoc networks can be cheaper to build because they don’t
require as much hardware..

Wireless networks can operate in one of two modes: infrastructure or ad hoc.

In infrastructure mode, all devices on a wireless network communicate with each other
through an access point (wireless router).
In ad hoc mode, a computer with a wireless network adapter communicates directly
with a printer equipped with a wireless print server.

COMPARISM BETWEEN INFRASTRUCTURE AND ADHOC

NETWORK CONFIGURATION MODE

  Infrastructure Ad hoc
Characteristics

Communication Through an access point Directly between devices

Security More security options WEP or no security

Range Determined by the range and Restricted to the range of

number of access points individual devices on the
network

Speed Usually faster Usually slower

Requirements for all devices

Unique IP address Yes Yes

for each device

Mode set to Infrastructure mode Ad hoc mode

  Infrastructure Ad hoc
Same SSID Yes, including the access Yes
point

Same channel Yes, including the access Yes

point

Advantages of Infrastructure mode over adhoc

 Increased network security

 Increased reliability
 Faster performance
 Easier setup
WIRELESS NETWORK SECURITY
A wireless network is a network which enables us to connect computers, printers and
other network devices through radio signals. Small wireless networks tend to be
cheaper to set up as wired networks as no wires are needed here. They are very
scalable and enable several devices to simultaneously use the same wireless
connection.
NORMS
Wireless standards are a set of services and protocols that dictate how WI-FI network
act. Below are the common wifi standard is the IEEE 802.11, the one being in use now
is the IEEE802.11ac which in some time may be replaced by the next generation
standard 802.11ax.
Below are some wireless network standards.
Norm name speed Frequency Year

802.11 2.4 GHz 1997

802.11a Wi-Fi 2 6 to 24 Mbps 5 GHz 1999

54
Mbps(maximum)
802.11ac Wi-Fi 5 5 GHz 2014

802.11ax Wi-Fi 6 2.4/5 GHz 2019

802.11ax Wi-Fi 6E 6 GHz 2019

802.11n Wi-Fi 1 11 Mbps 2.4 GHz 1999

802.11b

802.11g Wi-Fi 3 54 Mbps 2.4 GHz 2003

802.11n Wi-Fi 4 100 Mbps 2.4/ 5 GHz 2008

TYPES OF WIRELESS NETWORKS
There are several types of wireless networks, they include:

802.11b
802.11g
802.11n
802.11ac
802.11ax 10Gbps

WPAN
It is a set of devices interconnected within a very small area.
ADVANTAGES
Very reliable
Fully secured network
DISADVANTAGES
Slow data transfer rate.

Smaller range

WLAN
It links two or more devices over a short distance and connects users to the internet.
ADVANTAGES
Easy to add or remove workstation
Provide high data transfer rate due to small coverage
Not expensive to establish
DISAVANTAGES
Requires license.
Covers limited area.
Easily affected by weather.
WMESH
It is a wireless network of computing devices that are organised in a mesh topology.
ADVANTAGES
It is robust.
Easy fault diagnosis.
Provides security and privacy.
DISAVANTAGES
Installation and configuration become complex as we increase the number of
workstations.

WMAN
This is a wireless network formed from the interconnection of several LANs
ADVANTAGE
High security
DISAVANTAGES
Difficult to manage.
Internet speed difference.

WWAN
This is a wireless connection type used to cover large areas like towns and cities.
ADVANTAGES
Efficient
Secured

WGAN: Global area network

This refers to a network composed of different interconnected networks which cover
an unlimited amount of geographical area.
ADVANTAGES
Large coverage
DISAVANTAGES
costly
WIRELESS SECURITY
Wireless security is the prevention of unauthorised access or damage to computers or
data using wireless network which include wifi networks. The most common types of
wifi security are WEP(wired equivalent privacy ) and WPA(wifi protected access).
WEP provides a wireless network to provide security and privacy. WAP provides
more sophisticated data encryption and better user authentication than WEP. Versions
of WAP are WAP2, WAP3.
VULNERABILITIES OF A WIRELESS NETWORK
Wifi networks are very vulnerable to the following, especially when they are not secured.

Piggybacking
It implies anyone with a wireless network enabled device connecting to and using the
resources of an opened network.
Wardriving
This is a type of piggybacking in which a skilled user in the networks neighbourhood
but not in the range of the network, uses an antenna and internet to get access to the
network.
Evil Twin attack
Evil twin attack involves some person gathering information about a network and
impersonating the network using a signal of greater strength and amplitude than that of
the original network, in order for legitimate users to refer to it instead of real network.
Wireless sniffing
In this situation, skilled network and computer users use sniffing tools to steal
sensitive data from a network. Since traffic in unsecured network is not secured, any
one getting information from this network will get the alphanumeric values as typed.

Unauthorised computer access

This is a situation where someone gets unwanted and unauthorised access to your
computer to modify or steal data from it.
TYPES OF ATTACK THAT CAN BE LAUNCHED ON A
WIRELESS NETWORK
Wifi networks are vulnerable to a number of attacks, amongst which are;

Rogue Wireless Device

This involves an unauthorised WiFi device added onto a network and which is not
under the network administrator’s management, they provide gateway to potential
attackers. Most often they are added by staff who are not aware of their implications.
Peer-to-peer attack
This is an attack launched by a connected device to other devices connected to the same
network.
Eavesdropping
This is where a wireless network is monitored. It is of two types. Casual
eavesdropping or WLAN discovery is where a wireless client actively scans for
wireless access points.
Malicious eavesdropping on the other hand is where someone tries to listen to or
discover the data transfer between the client and an access point.
Encryption cracking
Here, attacker attempts to crack the encryption on the network. The most sensible
encryption to this attack is WEP which can easily be cracked in 5 minutes.
Authentication attack
Thius is where attacker scrapes a frame exchange between client authenticating with
the network, and then run an offline dictionary attack to find the client’s password.
MAC spoofing
This is the most easy attack. It involves stealing a client’s MAC address to later use it
to connect to the network.
Wireless Hijacking
This occurs when attacker configures their laptop to broadcast as a wireless access
point, using the same SSID as a public hotspot.
ATTACK MITIGATION
Peer-to0peer attack can be prevented by the process of Client Isolation which ensures
that clients connected to the same access point cannot communicate to each other.
Use wireless controllers which control and manage the functionalities of all access
points in the network, this mitigates evil twin and MITM attacks.
Use encryption protocols to avoid the data being transferred in the network in plane
text. WPA2 is recommended to be used, this helps to mitigate eavesdropping and
encryption cracking.
Employ AAA (Authentication, Authorisation and Accounting) for recording user
activity. An example of a server we can use to enable user authentication and
authorisation is RADIUS.
Use VPN to enhance security and avoid ac address spoofing.
Segregate the network to have a different vlan for guest users and network legitimate
users, or to separate the different parts/ department of network.
Use an authentication portal to have an additional security beyond initial
authentication and encryption mechanism, once connected, users can be directed to a
login page where they are required to enter their credentials before having access to
network services.
Use a Windows host based firewall which will protect you from untrusted devices in
the network. They can also be used in monitoring and login.
HOW TO SCALE A WIFI NETWORK

HIDDEN TERMINALNAL

DEFINITION
This is a situation where to or more nodes which are out of the range of each other
simultaneously transmit to the same recipient. This creates collision, it can be prevented
by using a MAC (medium access control) layer protocol IEEE 802.11 RTS/CTS
(Request To Send/ Clear To Send) and synchronising the different stations, giving
them the same frame size.
SETTING UP A WIRELESS NETWORK IN A LAN
Requirements
Decide the type of network we are to design
Enquire the size of the network
Select a position for the access point /wifi router.
Select a frequency band according to the network needs (2.4Ghz or 5Ghz).
Choose a transmission channel, use a wifi network analyser to find the enabled
networks around the area of our network to ensure the channel we are to use is free or
does not have too much traffic on it.
Enable the firewall settings on the router
CREATING AN ADHOC NETWORK AND ENABLING
EVERYONE TO CONNECT TO IT
To set An Ad hoc network in Windows 10 using command prompt, we take the
following steps:
Enable the WiFi adapter of your machine.
On the wifi of the computer.

Open the command prompt of one of the computers of the network.

Type the following command:
- -netsh wlan set hostednetwork mode=allow ssid=”network name” key=”the
network password”
- .
- -netsh wlan start hostednetwork.
To specify which of the resources/ files or data should be shared on the network.
- Right click on the file and go to properties
- Select sharing
- Click on share
- Select with who to share (everyone, or other)
- Select the sharing mode, that is read, write or read-write.
- Click on share/finish/ok, and the sharing can begin.
The other computers of the network go through the following procedure:
- Activate their Wifi
- Select from the list of available networks, the ID of our network.
- Type the network password.
- Go to network settings. Select our network name and they will be able to see
the computers on the network and access the shared data.