Know the following organizations that help define wireless:
Institute of Electrical and Electronics Engineers (IEEE): Creates the wireless standards, such as 802.11a/b/g/n
Federal Communications Commission (FCC): Regulates the use of wireless devices (licenses of frequencies)
WiFi-Alliance: Ensures compatibility of wireless components. The WiFi-Alliance is responsible for testing and certification of wireless devices.
Know the two types of wireless networks:
Ad hoc mode: No wireless access point is used. The wireless clients communicate in a peer-to-peer environment.
Infrastructure mode: Uses a wireless access point
Know the IEEE Standards for wireless:
802.11a: A wireless standard that uses the 5 GHz frequency range and runs at 54 Mbps.
802.11b: A wireless standard that uses the 2.4 GHz frequency range and runs at 11 Mbps. The WiFi standard was created and 802.11b is part of that standard. This is the frequency used by cordless phones and microwaves, so you may experience interference from those devices. As a correction, you can change the channel of the wireless network or purchase phones that use a different frequency.
802.11g: A wireless standard, which is compatible with 802.11b, that also uses the 2.4 GHz frequency range and runs at 54 Mbps.
802.11n: A new wireless standard that can use either the 2.4 GHz frequency range or the 5 GHz frequency range and is compatible with 802.11a/b/g. 802.11n has a transfer rate of approximately 150 Mbps.
Other wireless terms to know for the exam:
Basic Service Set (BSS): A wireless network consisting of one access point using an SSID. If you had three access points, each using a different SSID, then this would be three BSS networks.
Extended Service Set (ESS): A wireless network comprising multiple access points using the same SSID.
Be sure to know the configuration requirements to set up an ESS:
The SSID on each access point must be the same.
The range of the access points must overlap by 10% or more.
Each access point must use a different channel.
Know the difference between the different wireless encryption types:
Wired Equivalent Privacy (WEP): An old wireless encryption protocol that involves configuring a pre-shared key on the access point and the wireless client that is used to encrypt and decrypt data. WEP uses the RC4 encryption algorithm with the pre-shared key and is not considered secure due to the way the key is used. WEP supports 64-bit and 128-bit encryption.
WiFi Protected Access (WPA): The improvement on WEP that adds the TKIP protocol in order to perform key rotation to help improve on the fact that WEP uses a static key. WPA has two modes: personal mode involves configuring a pre-shared key, and enterprise mode can use an authentication server such as RADIUS.
WiFi Protected Access 2 (WPA2): Improves upon WPA by changing the encryption algorithm to the Advanced Encryption Standard (AES) and supports both personal mode and enterprise mode.
The following are some key points regarding best practices to improve the security of your wireless network:
Disable wireless: If you aren't using wireless, then disable the wireless functionality on the wireless router.
Change the SSID: Make sure you change the SSID to something meaningless. You don't want the SSID set to a value that will help the hacker identify the building you're in because he could move closer to the building to get a stronger signal.
Disable SSID broadcasting: After disabling SSID broadcasting. the router won't advertise the existence of the wireless network. This makes it harder for someone to connect because they have to manually configure their client for the SSID name.
Implement MAC filtering: MAC filtering allows you to limit who can connect to the wireless network by the MAC address of the network card.
Implement encryption: Be sure to encrypt wireless traffic with WEP, WPA, or WPA2. WPA2 is the most secure of the three.
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