Chapter 14 Wireless Networking

What channels does WAP like?

1,6,11, because they are non overlapping channels

how many channels on the 2.4Ghz network?

14 channels at 120 MHz

What frequencies where originally used for 802.11 standard?

2.4 Ghz 5 Gz

How many channels are available on 5 Ghz network?

40

greenfield mode

802.11n devices only WAP will only accept 802.11n frames everything else is dropped

legacy mode

802.11n that transmits separate packets just for legacy devices. it is a fall back if other methods don't work

Transmit Beamforming (TxBF)

A method that allows a MIMO transmitter using multiple antennas to adjust the phase and amplitude of the outgoing transmission in a coordinated method. eliminates dead spots

MAC address filtering

A method that enables you to limit access to your network based on the physical addresses of wireless NICs.

802.11n

A wireless network standard that defines speeds of up to 600 Mbps. It is downward-compatible with 802.11a, 802.11b, and 802.11g. (13) range 300ft ODFM (QAM) spectrum

802.11i

A wireless standard that added security features. authentication and encryption

SSID broadcast

An access point's broadcasting of the network name, this is how you are able to see networks in your area

wireless network

Any type of computer network that is not connected by cables of any kind. uses radio frequency RF to enable devices to communicate with one another

aside from the layer 1 difference between wired and wireless connections, what is the major difference between the two?

Both send data encapsulated but wired connections use electrical impulses while wireless uses radio waves to send packets

What are the two ways CSMA/CA avoids collisions?

DFC and RTS/CTS(ready to send clear to send

802.11 spread-spectrum broadcasting methods

DSSS direct sequence spread specturm FHSS Frequency hopping sporead spectrum OFDM orthogonal frequency-division multiplexing

802.11 standard for collision avoaidance

Distributed Coordination Function DCF (only one implemented currently) Point Coordination Function PCF

What standard makes sure that all of this communication is encrypted?

EAP

EAP-TLS

EAP with Transport Layer Security defines the use of a RADIUS server as well as mutual authentication, requiring certificates on both the server and every client. Client side, a smart card may be used in lieu of a certificate. Very robust, and the most secure wireless networks use EAP-TLS.

EAP-FAST

EAP-Flexible Authentication via Secure Tunneling--Designed by Cisco to replace LEAP. all current running systems support it

ESS

Extended Service Set

what is a network called that has more than one WAP?

Extended service set

EAP-TTLS

Extensible Authentication Protocol-Tunneled Transport Layer Security similar to EAP-TYL but it only uses a singe server side certificate common in more secure wireless networks

mixed mode

I am a wireless access point setting. I would utilize this mode if I have different wireless standards on my network.

what was the original wifi standard?

IEEE 802.11 1997

What security is provided between the RADIUS and the NAS?

IPsec

IBSS

Independent Basic Service Set basic unit of organization in wireless networks

How does a wireless network detect collisions?

It is a lot like a wired network, except it is not csma/cd it is now carrier sense multiple access collision avoidance csma/ca

What is the security like with WPS?

It is not very good. If you use WPS be aware that it is easily hijackable since the PINs aren't usually very long

LEAP

Lightweight Extensible Authentication Protocol proprietary to CISCO combo of MS-CHAP authentication btwn client and RADIUS server

BSSID

MAC address of an access point basic service set identifyer

MU-MIMO

Multi-user Multiple-input Multiple-output gives WAP the ability to broadcast to multiple users silumtaneously

802.11n and 802.11ac devices use a special version of _______ called ________.

OFDM QAM quadruple amplitutde amodulated

OFDM

Orthogonal Frequency Division Multiplexing newest member to 802.11 on all networks today outside of some of the earliest networks

What security is provided between the supplicant and the NAS?

PPP

whitelist

Permitting nothing unless it appears on the list.

RADIUS

Remote Authentication Dial-In User Service

SSID

Service Set Identifier aka network name 32bit id string that's inserted into the header of each frame processed by WAP

802.1X

The IEEE standard that defines port-based security for wireless network access control puts EAP info inside Ethernet frame.

EAP-MD5

Very simple version of EAP which uses only MD5 hashes for transfer and authentication credentials. It is weak and the least used of all versions of EAP.

In an ESS, every ___ connects to a central _________ to become part of a single _______

WAP broadcast domain switch or switches

Infrastructure uses one or more ___ to create a ____ topology called a ______.

WAP star WLAN

What purpose does a wireless access point serve?

WAP is a device designed to interconnect wireless network nodes with wired networks. It acts as sort of a hub for wifi.

WPS

WiFi Protected Setup

IEEE 802.11

Wireless Ethernet standard more commonly known as Wi-Fi. defines how devices communicate and how to secure that connection

WPA

Wireless Protected Access, 802.1i standard for encryption dynamic encryption key generation issued per session uses TKIP and RC4 ciphers

802.11b

Wireless networking standard that operates in the 2.4-GHz band with a theoretical maximum throughput of 11 Mbps. 300 ft

802.11g

Wireless networking standard that operates in the 2.4-GHz band with a theoretical maximum throughput of 54 Mbps and is backward compatible with 802.11b. 300 foot range OFDM

802.11ac

Wireless networking standard that operates in the 5-GHz band and uses multiple in/multiple out (MIMO) and multi-user MIMO (MU-MIMO) to achieve a theoretical maximum throughput of 1 Gbps. 300ft range

802.11a

Wireless networking standard that operates in the 5-GHz band with a theoretical maximum throughput of 54 Mbps. 150ft range

Does a shared network require authentication or authorization?

Yes it requires both

channel bonding

____ is an 802.11n feature that allows two adjacent 20-MHz channels to be combined to make a 40-MHz channel.

What are the two modes for wireless connectivity?

ad hoc infrastructure

How can you extend the service area in a infrastructure method of 802.11?

adding more acces points, called ESS

mixed mode

aka high throughput mode, 802.11a-htl, 802.11g-ht has a higher bandwidth

BSS

basic service set area of one WAP

What types of systems benefit from infrastructure methodology?

big businesses and larger networks that share dedicated resources like internet and databases

supplicant

client wireless computer

access control

controls access to the network itself

What are three solutions in place to improve wifi security?

data encryption MAC address filtering authentication

What two kinds of software are needed for wireless?

device driver for wireless NIC configuration utility

What is the biggest problem with Wifi security?

devices right out the box have no security. what prevents another piece of hardware from grabbing the radiowaves out of the air and using them?

DSSS

direct secure spread spectrum sends data out on different frequencies at the same time capable of greater data throughput

How does encryption in wireless networks work?

electronically scrambled data packets and locks them with an encryption key before transmitting then onto the wireless network the receiving pc unscrambles the packet and processes the data WPA2

What exactly is EAP?

even though it says it is a protocol it is more of a PPP wrapper

FHSS

frequency hopping spread spectrum sends data on one frequency at a time constantly hopping between different frequencies

the actual number of usable bits per second is called

goodput

signal strength

how well your wireless device is connecting to other devices

native mode

if all devices on 802.11g network are 802.11g devices then they will have 54mbps OFDM spectrum

802.11X

increased security abilities of wireless networks. encryption authentication using a RADIUS server passwords encrypted with Extensible Authentication Protocol EAP

What needs to happen for backwards compatibility on the 802.11n standard?

just encapsulate 802.11n frame inside the previous version's frame, what adds even more overhead and latency to the system

What modes can WAPs transmit in?

legacy mode mixed mode greenfield mode

blacklist

list of things you do not grant access to on the network period

what does a connection type of 802.11g-ht mean?

means that it is connecting to an 802.11n WAP running mixed mode

Ad hoc uses a ____ topology instead of a ____.

mesh WAP

EAP-MS-CHAPv2

more commonly known as PEAP uses pw function based on MS-CHAPv2 with the addition of an encrypted TLS tunnel. MOST COMMON IMPLEMENTATION

MIMO

multiple in multiple out enabl,es devices to make multiple simultaneous connections called streams used in systems with lots of antennae

NAS

network access server the WAP

Does an open network require authentication or authorization?

no

Is MAC address filtering completely effective?

no because of MAC spoofing. someone saying they are a specific MAC that isn't. even this wont stop them from taking it out the air. If you are really concerned you should make sure your network is wired to provide the best protection

Asymetric Encryption

parties use public and private keys

channel

portion of the spectrum that's available

What is one of the biggest issues with wireless networks, and how is it addressed?

potential interference may cause a problem, but allowing different devices to function on different frequencies fixes this problem

EAP-PSK

preshared key, both ends have a preshared secretcode stored on both sides

Downside to 802.11b?

prone to interference on 2.4 GHz

What modes does WPS work in?

push button mode (like on xbox you push a button and it connects) PIN method you have to use the pin located on the WAP box to connect

How do ad hoc networks participate in BSSID when they have no WAP?

random 448 bit string that looks like MAC and that BSSID goes into every frame

What types of groups benefit from ad hoc?

small groups of computers that need to transfer files or print usually.

DFC

specifies rules for sending data onto the network media. sends out data until there is an ACK

How do you connect in a 802.11X?

supplicant contacts NAS, which sends UN and PW to RADIUS server, RADIUS sends packet to supplicant through WAP w access accept code and authenticator section that proves the packet came from RADIUS server.

What is good to remember when thinking about setting up a WAP?

the range is not accurate, cut it in half. range on packaging describes an ideal environment

Every device on the wifi network must share

the same SSID

symmetric encryption

the same key is used to encode and decode

What happens to frames that don't have the right MAC address?

they get dropped

ad hoc

two or more devices comunicate directly without any other hardware

infrastructure

use a WAP that acts as a hub for all wireless clients

Problems with WEP

uses cipher called RC4 uses code called intitialization vector of 24 bits leaving 40 or 104 bits left for encryption encryption key is static and doesnt change no user authentication dont use it, outdated and unsafe

roaming

when you travel in between WAPs and the transitions is seamless

link state

whether your device is connected

WEP encryption

wired equivalent privacy 802.11a and 802.11b 64 128 256bit easy to crack due to how keys are produced

how do you know the network name in ESS network?

you use the ssid but it is called essid when in ess network