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Wireless Networks Tamus, Zoltán Ádám zoltanadam_tamus@yahoo.com http://adaminf.atw.hu
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Basics of Communication Transmitter (coding)->Channel->(decoding) Receiver
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The Radio-Channel Wireless technologies use electromagnetic waves as channel Radio waves (freq. 30 kHz-30 GHz) Light (Infra Red) (wavelength ~900 nm)
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Personal Area Networks Interconnecting devices without wire Headsets Notebooks PDA (Personal Digital Assistant) Mobile phones GPS Peripherals (Keyboard, Mouse, Printer, Game controller etc.)
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Bluetooth 1998, Special Interest Group (Ericsson, IBM, Intel, Nokia, Toshiba) Uses radiofrequency: in the 2.4 GHz band, frequency hopping spread spectrum system Max. 1 Mb/sec bandwidth Operating range ~10 m, but in high power applications can be extended to 100 m Personal Area Networks
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Personal Area Network Bluetooth devices
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Personal Area Network IrDA (Infrared Data Association) 1993 Use Infrared light Operating range max. 1 m Bandwidth: 4 Mb/sec.
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Local Area Networks Home Offices Public WLAN, Wi-Fi Hot Spots Hotels Airports Net Cafes http://www.wi-fihotspotlist.com/http://www.wi-fihotspotlist.com/ http://www.hotspotter.hu/en/ http://www.hotspotter.hu/en/ http://www.wi-fihotspotlist.com/http://www.hotspotter.hu/en/ Ad Hoc peer to peer
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Local Area Network Typical WLAN application in home or small office
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Local Area Network Network Access in Buildings Desktop PCs Notebooks PDAs
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Local Area Networks IEEE 802.11 standard 802.11a 1999 5 GHz band Max. 54 Mb/sec 802.11b 2.5 GHz Max. 11 Mb/sec 802.11g 2.5 GHz Max. 54 Mb/sec
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Security Eavesdropping & Espionage Wireless technologies use radio waves. Eavesdroppers can easily pick up unencrypted messages by listening the ether Rouge Access Points An employee of an organization might hook up an access point without the permission or even knowledge of IT.
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Accidental Associations A wireless network is setup using the same SSID as your network and within range of your wireless device. Connecting to another wireless LAN can divulge passwords or sensitive document to anyone on the neighbouring network Denial of Service Flowing packages to the network take the resources RF interference with an external transmitter Security
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Security Securing Wireless Networks WEP (Wired Equivalent Privacy) Problems: Easily vulnerable because of the permanent keys and the short initialization vector WPA (Wi-Fi Protocol Access) The clients use periodically changed different keys VPN (Virtual Private Network)
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Authentication SSID (Service Set Identifier) Weakness in IEEE 802.11: the SSID is sent without encrypting! MAC address filtering MAC (Media Access Control) WEP not encodes the MAC field of the frame! Security
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Setting up a wireless router Connection to the broadband router Connecting a PC
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Access to Web-based utility software by Router’s IP address User Name: User Name: Password: admin Configuration
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Setting up Internet Connection DHCP Static IP PPPoE PPTP
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Setting up Wireless Network Mode: B/G SSID Broadcasting ? Channel
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Security Settings WEP Level of WEP encryption: 64-bit or 128-bit
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WPA WPA2 WPA2 Mixed Set the Passphrase and Renewal period Security Settings
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Access control MAC address filtering
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Security Precautions Change the default SSID. Disable SSID Broadcast. Change the default password for the Administrator account. Enable MAC Address Filtering. Change the SSID periodically. Use the highest encryption algorithm possible. Use WPA if it is available. Please note that this may reduce your network performance. Change the WEP encryption keys periodically.
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