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BSIT 07-11

BZUPAGES.COM

BSIT 07-11

ON

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DanisHussain o7-o9

Taha Khan o7-o6

Imran Khan o7-37

Farrukh Ali o7-43

BSIT 07-11

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• Introduction• Wi-Fi Technologies• Wi-Fi Architecture & Types• Wi-Fi Network Elements• Types of Hardware• How a Wi-Fi Network Works• Applications of Wi-Fi• Wi-Fi Security• Advantages/ Disadvantages of Wi-Fi

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• Wireless Technology is an alternative to Wired Technology, which is commonly used, for connecting devices in wireless mode.

• Wi-Fi (Wireless Fidelity) is a generic term that refers to the IEEE 802.11 communications standard for Wireless Local Area Networks (WLANs).

• Wi-Fi Network connect computers to each other, to the internet and to the wired network.

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•Wi-Fi or 802.11b/g is the wireless standard used for local area networks operating at 2.4GHz.

• Virtually every new laptop and mobile being sold today comes already equipped with a compatible wireless WiFi adapter. •The WiFi dial-up wireless router is compatible with either 802.11b or 802.11g adapters and allows local network data transfers at speeds of up to 11Mbps (megabits per second).

• All Intel Centrino laptops as well as adapters marked 802.11a/g are compatible.

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Wi-Fi Networks use Radio Technologies to transmit & receive data at high speed:

• IEEE 802.11b• IEEE 802.11a• IEEE 802.11g

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• Appear in late 1999• Operates at 2.4GHz radio spectrum• 11 Mbps (theoretical speed) - within 30 m

Range• 4-6 Mbps (actual speed)• 100 -150 feet range• Most popular, Least Expensive• Interference from mobile phones and Bluetooth

devices which can reduce the transmission speed.

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• Introduced in 2001• Operates at 5 GHz (less popular) • 54 Mbps (theoretical speed)• 15-20 Mbps (Actual speed)• 50-75 feet range• More expensive• Not compatible with 802.11b

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• Introduced in 2003• Combine the feature of both standards

(a,b)• 100-150 feet range• 54 Mbps Speed• 2.4 GHz radio frequencies• Compatible with ‘b’

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• Access Point (AP) - The AP is a wireless LAN “base station” that can connect one or many wireless devices simultaneously to the Internet.

• Wi-Fi cards - They accept the wireless signal and relay information.They can be internal and external.(e.g PCMCIA Card for Laptop and PCI Card for Desktop PC)

• Safeguards - Firewalls and anti-virus software protect networks from uninvited users and keep information secure.

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Antennas come in all shapes and styles:

Omni-directional: Vertical Whip Ceiling mount

Directional: Yagi (“Pringles can”) Wall mounted panel Parabolic dish

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Wi-Fi Architecture

& Types

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We can manage the WLAN (wireless local area network) with several types:

Ad-Hoc Mode Mesh Mode Infrastructure Mode

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Peer-to-peer setup where clients can connect to each other directly. Generally not used for business networks.

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Mobile stations communicate to each other directly.

It’s set up for a special purpose and for a short period of time.

For example, the participants of a meeting in a conference room may create an ad hoc network at the beginning of the meeting and dissolve it when the meeting ends.

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Every client in the network also acts as an access or relay point, creating a “self-healing” and (in theory) infinitely extensible network. Not yet in

widespread use, unlikely to be in homes.

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There is an Access Point (AP),There is an Access Point (AP), which becomes the hub of a “star topology.”which becomes the hub of a “star topology.”

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There is an Access Point (AP), which becomes the hub of a “star topology.”

Any communication has to go through AP. If a Mobile Station (MS), like a computer, a PDA, or a phone, wants to communicate with another MS, it needs to send the information to AP first, then AP sends it to the destination MS

Multiple APs can be connected together and handle a large number of clients.

Used by the majority of WLANs in homes and businesses.

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• Basic concept is same as Walkie talkies.• A Wi-Fi network is created by installing an

access point to an internet connection.• An access point acts as a base station.

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•A single access point can support up to 30 users A single access point can support up to 30 users and can function within a range of 100 – 150 feet and can function within a range of 100 – 150 feet indoors and up to 300 feet outdoors.indoors and up to 300 feet outdoors.

• Many access points can be connected to each Many access points can be connected to each other via Ethernet cables to create a single large other via Ethernet cables to create a single large network.network.

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Wireless Security

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• Wireless technology doesn’t remove any old security issues, but introduces new ones• Eavesdropping• Man-in-the-middle attacks• Denial of Service

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• Easy to perform, almost impossible to detect• By default, everything is transmitted in clear

text• Usernames, passwords, content ...• No security offered by the transmission medium

• Different tools available on the internet• Network sniffers, protocol analysers . . .• Password collectors

• With the right equipment, it’s possible to eavesdrop traffic from few kilometers away

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1. Attacker spoofes a disassociate message from the victim

2. The victim starts to look for a new access point, and the attacker advertises his own AP on a different channel, using the real AP’s MAC address

3. The attacker connects to the real AP using victim’s MAC address

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• Attack on transmission frequecy used• Frequency jamming• Not very technical, but works

• Attack on MAC layer• Spoofed deauthentication / disassociation messages• can target one specific user

• Attacks on higher layer protocol (TCP/IP protocol)• SYN Flooding

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The requirements for Wi-Fi network security can be broken down into two primary components:

• Authentication User Authentication Server Authentication

• Privacy

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• Keeping unauthorized users off the network• User Authentication

• Authentication Server is used• Username and password • Risk:

• Data (username & password) send before secure channel established

• Prone to passive eavesdropping by attacker

• Solution• Establishing a encrypted channel before sending

username and password

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• Server Authentication• Digital Certificate is used• Validation of digital certificate occurs

automatically within client software

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• Home• Small Businesses • Large Corporations & Campuses• Health Care• Wireless ISP (WISP)• Travellers

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• Mobility• Ease of Installation• Flexibility• Cost• Reliability• Security• Use unlicensed part of the radio spectrum• Roaming• Speed

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• Interference• Degradation in performance• High power consumption• Limited range

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AnY Qu3sTioN??

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