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Fundamentals of Networking Discovery 1, Chapter 7

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Objectives Describe wireless technology Describe the various components & structure of a wireless LAN Describe wireless security issues and mitigation strategies Configure an integrated wireless access point and wireless client

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Understanding Wireless Electromagnetic Spectrum Radio, TV, Light, X-Rays, Gamma Rays Each has a specific wavelength Like the distance between waves Wireless uses Electromagnetic Waves Same as carrying radio signals Well discuss the most common wavelengths

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Infrared (IR) Low energy Cant go through walls, short range (30) Line of sight One to one communication Wireless Mice & Keyboards, Remotes, PDA Infrared Direct Access (IrDA) port

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IR & Your TV Your TV remote has an infrared LED inside Switches on & off to create 0s and 1s when you push a button Push a button to send a 7 digit sequence of 0s & 1s Sony TV Channel Up is 0000011, channel down is 0010001

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Radio Frequency (RF) Wireless LAN, cordless phone, Bluetooth LAN & Phone Signal travels through walls, longer range, higher power 900 MHz, 2.4 GHz and the 5 GHz frequency Bluetooth Low speed, short range, lower power One to many devices Uses 2.4GHz Starting to use Bluetooth for wireless mice, etc.

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Activity- Which is it?

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Review Bluetooth or RF. Which has higher power output? RF Two doctors are beaming their business cards to each other through their PDAs. Which signal is being used? IR

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Wireless Benefits

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Wireless Limitations Many devices use wireless Cordless Phones 2.4GHz Interference Microwave Ovens Interference Range Solid Walls a problem Not as fast as, or reliable as, wired Security Wireless is east to access & can be intercepted Authentication & Encryption now used

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Types of Wireless Networks WWAN WLAN WPAN

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WPAN- SMALLEST Wireless Personal Area Network Used to connect wireless mice, keyboards & PDAs to computer IR or Bluetooth Short Range Device to device Peer to peer

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WLAN Wireless Local Area Network RF IEEE 802.11 standards Users connect to a wired network through an Access Point (AP) Medium range

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Access Point Between your wired equipment and your wireless devices

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WWAN Wireless Wide Area Network Cell phone network GSM, CDMA Long range Government regulated

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Wireless Networks WPANWLANWWAN Standard Range Uses

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Review

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Wireless Standards Specifies data speed, range, RF spectrum IEEE standards, Wi-Fi 802.11a, 802.11b, 802.11g and 802.11n Wi-Fi Alliance tests devices from manufacturer Will work with other devices w/ same logo

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802.11b 1999 2.4GHz 11Mbps 150ft range indoors 300 ft range outdoors

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802.11a 1999 5GHz Unused at that time Less congestion 54Mbps (faster than B) NOT compatible with b/g/n 75ft-150ft range Originally too expensive Now hard to find

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802.11g 2003 2.4GHz 54Mbps 150ft range indoors 300 ft range outdoors Compatible with 802.11b

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802.11n 2.4Ghz Up to 750ft range Backwards compatible b/g

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Wireless Components Access Point Connects wireless devices to wired network Client Any host device that connects to wireless Also known as STA (station) Bridge Antenna

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Omni-Directional Antenna Equally in all directions Found on APs

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Directional Antenna Concentrate signal in one direction Better distance Connects networks 25 miles or more apart Bridge to Bridge- connects 2 networks wirelessly

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Want a bridge? Aironet 1400 Find it on www.cdwg.comwww.cdwg.com

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Activity

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WLANs & the SSID Your WLAN has to be identified

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SSID-Service Set Identifier Tells wireless devices which WLAN they belong to & which other devices they can communicate with Case-sensitive & up to 32 characters All of your devices MUST have same SSID Broadcast or Not?

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WLAN Install 1:Ad-hoc Mode- IBSS Wireless devices can talk to each other without involving Access Point Peer-to-peer or small networks Less $$$, no AP

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WLAN Install 2: Infrastructure Mode- BSS Most used AP/Router controls communication Access to Internet Basic Service Set (BSS) Area covered by a single AP

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Cover More Areas Connect many BSSs to get expanded area You get an ESS, Extended Service Set Areas should overlap Think about this school & coverage

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Question?

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Lab Activity 7.2.3.4 Setting the SSID on an AP READ THE INSTRUCTIONS!!! Click Topology, then the host View browser, follow directions

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Wireless Channels Used to control multiple conversations Like how all of your TV channels travel across a cable Divides up the 2.4GHz for each conversation Selection of channels is usually automatic Sometimes they use a single wide channel to get more bandwidth

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Going to a Concert General Admission compared to tickets for a seat Whats the different experiences? Wireless has a method to avoid collisions A ticketing system

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Wireless Detecting Collisions CSMA/CA Reserves a channel for conversation No one else may use that channel Request to Send (RTS) to the AP If available, a Clear to Send (CTS) is sent OK to send Broadcast is sent to all, notifying channel in use ACK sent to AP to notify done All devices see ACK & know channel is open

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CSMA/CA- (7.2.4.2)

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Activity- Setting the Channel 7.2.4.3 Most of the time, automatic is fine

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Configuring an AP

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Configuring the Client What is a wireless host known as? STA (station) Its a device with wireless NIC & software for it Settings MUST match AP SSID, security settings, and channel

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Configuring the Client- Software As part of the OS OR supplied with Wireless NIC Contains link info, profiles, etc. Usually the OS one is okay

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Now Test It Look at signal strength Then test data transmission Use the ping test Ping another PC 1 st If that doesnt work, ping the AP

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Lab 7.2.5.3 & 7.2.6.4 Configure the AP and Wireless Client Test

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Wireless Security Tradeoff: Ease & convenience of availability vs. putting info to the airwaves What can they do? Use your Internet for FREE Access your computers Damage files Steal private info SolutionSET UP SECURITY!

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Why is security important? Its possible that an individual or a business owner can be held responsible for what an unauthorized user does with your network Computer Fraud Law Accessing a computer without authorization

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Getting In Easily

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Take Security Measures Use all of the following to secure your wireless network: 1.Change the router password from the default 2.Change the SSID & disable the broadcast 3.Use MAC Address Filtering 4.Authentication (PSK) 5.Encryption (WPA)

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Change the Password!

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Change SSID & Disable Broadcast Problem SSID must be known to connect Broadcast by default Solution TURN SSID BROADCAST OFF!! Change the default settings SSID Passwords IP addresses These solutions help, but you can still be hacked!

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The SSIDs- Discovered!!!

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Get your MAC Addresses

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Set up MAC Address Filtering

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MAC Address Filtering Use your devices MAC address to limit connectivity to you KNOWN devices You pre-configure the MACs in the AP The AP will check its list Only those in list will connect

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MAC Address Filtering What could go wrong? Typo on the MAC address New devices cant enter network without adding Mac to the AP configuration MAC address cloning 1.Sniff network traffic (MAC address in packet) 2.Find MAC addresses on that network 3.Change your MAC address to match one on the target network.

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Sniffing to Clone

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Authentication to the AP Permitting entry to network Like username & password Works with encryption methods Occurs before client connects to WLAN 3 types: Open (Default) PSK (Used at home) EAP (Used at big businesses)

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Open Authentication Default Anyone can connect

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Pre-Shared Keys (PSK) Authentication AKA Personal Same passphrase set on AP & Client Client asks AP to connect One way

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Pre-Shared Keys (PSK) Authentication AKA Personal Same passphrase (or key) set on AP & Client Client asks AP to connect One way

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EAP Authentication (Enterprise) Two-way PLUS username/password Talks to RADIUS server Has database of allowed clients In medium to large businesses

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Authentication & MAC Filter Authenticate 1 st MAC Filtering 2 nd These hacker from gaining access only!

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Encryption Protect data traveling through the air Prevents signal from being intercepted Sniffing WEP WPA Personal (WPA-PSK; WPA Personal) WPA2 Personal (WPA2-PSK; WPA2 Personal)

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WEP Wired Equivalency Protocol All devices use same WEP key 64 or 128 bits long Set up using a passphrase Generates Key 1 to use WEAK!!!! Same static key

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WPA or WPA2 Wi-Fi Protected Access 64 to 256 bits long New key each time client connects to AP Pick how it encrypts TKIP (Temporal Key Integrity Protocol) AES (Advanced Encryption System)

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Review WEP/WPA _______________ the data. Encrypt PSK/EAP are used to _____________ the user to the WLAN. Authenticate WEP or WPA. Which is stronger? WPA Whats the difference between open authentication & PSK? PSK has the secret key

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Activity 7.3.4.3 Configure encryption and authentication

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Access Restrictions You can control the type of data Entering or leaving the AP Going to/from a specific MAC or IP Block by port # Time

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Lab 7.3.5.2 Configuring Wireless Security

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Planning the WLAN Determining the type of wireless standard to use Determining the most efficient layout of devices An installation and security plan A strategy for backing up and updating the firmware of the wireless devices.

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Wireless Standard Bandwidth requirements, coverage areas, existing implementations, and cost. This information is gathered by determining end-user requirements. Ask the following What throughput is actually required by the applications running on the network? How many users will access the WLAN? What is the necessary coverage area? What is the existing network structure? What is the budget?

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Planning the WLAN Which 802.11 standards support a larger BSS? Means less equipment to buy Is there an existing standard in use? Total Cost of Ownership (TCO) which includes the purchase of the equipment as well as installation and support costs

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Installation of Devices Site Survey Measurements Consider interference sources & locations

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Install & Secure the AP

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Back It Up!!! 7.4.3.2 Activity Home & Small Business Select Backup Configuration in Menu To restore, select it Factory Default Setting

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Updating the Firmware The OS of the device is in firmware Update for new features, etc 1.Get the current version 2.Research issues & features that may cause you to want the upgrade 3.Download it to a HD (directly connected machine) 4.Select Firmware upgrade DO NOT INTERRUPT THE PROCESS!

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7.4.4.2 Activity Upgrade the firmware

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Review

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Advanced Review

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Fundamentals of Networking Discovery 1, Chapter 7