Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
80 Cards in this Set
- Front
- Back
|
AD hoc WLAN is aka?
|
IBSS
|
|
|
What is IBSS?
|
Independent Basic Service Sets, has no AP, hosts connected together
|
|
|
What is BSS?
|
Basic Service Set, WLAN has only one AP for all hosts
|
|
|
What is ESS?
|
Extended Service Set WLANS with multiple AP
|
|
|
AD hoc WLAN is aka?
|
IBSS
|
|
|
What are cells?
|
Overlapping areas of coverage
|
|
|
What is the wireless IEEE stnandard?
|
802.11x
|
|
|
What is the frequency, rate and range for 802.11a?
|
5GHz, 25-54MBPS, indoor range is 100ft
|
|
|
What is the frequency, rate and range for 802.11b?
|
2.4GHz, 6.5-11MBPS, indoor range is 100ft
|
|
|
What is the frequency, rate and range for 802.11g?
|
2.4GHz, 25-54MBPS, range is 100ft
|
|
|
What is the frequency, rate and range for 802.11n?
|
2.4 or 5GHz, 200-540MBPS, 160ft
|
|
|
True or false? Infrared provides high data rate but very short range?
|
True
|
|
|
What is Spread Spectrum?
|
A method of spreading a signal over a range, or spectrum, or frequencies
|
|
|
What is FHSS?
|
Frequency-hopping spread spectrum- method where the sender and receiver agrees on the range and frequency to use and during transmission the signal will be sent over this range
|
|
|
What is DSSS?
|
Direct Sequence Spread Spectrum is a method where the signal is spread over the entire range of frequencies at once. Signal does not hop around between frequencies like the FHSS.
|
|
|
Which wireless uses DSSS?
|
b,g and n
|
|
|
What is OFDM?
|
Orthogonal Frequency Division Multiplexing splits the signal and sends the signal fragments over the different frequencies at the same time.
|
|
|
What are 3 good reasons to spread spectrum methods?
|
1. Increase resistance to noise
2. Allow sharing of a frequency 3. More difficult to intercept |
|
|
What is a yagi antenna?
|
A directional or point-to-point antenna which sends its signals in a single direction.
|
|
|
What are yagi antennas good for?
|
Briding the distance between WAPs.
|
|
|
What is a Omni antenna?
|
Omnidirecitional or point-to-multipoint antenna which sends signals in all directions
|
|
|
True or false? Omni Antennas would be good for connecting hosts which move about and travels from place to place.
|
True
|
|
|
What is CSMA/CA?
|
Carrier sense multiple access with collision avoidance
|
|
|
What is the process of CSMA/CA?
|
1. Host listens to see if there are any transmissions
2. If not, host invokes random timer, listens again and then transmits 3. If channel is busy then host cannot transmit |
|
|
True or False? In CSMA/CA collsions are detected but not voided.
|
False, collisons are not detected but avoided
|
|
|
True or False? With CSMA/CA, jam signals are sent over the wireless network?
|
False. Jam signals are not sent over the wireless network.
|
|
|
True or False? Wireless are can operate a full-duplex.
|
False, wireless are limited to half-duplex
|
|
|
What is SSID?
|
Service Set Identifier, client's SSID has to match the APs for communication to proceed
|
|
|
Is SSID case-sensitive and what is the max length of characters?
|
Yes and max length is 32 characters
|
|
|
What is WEP?
|
Wired Equivalent Privacy
|
|
|
What are the main problems with WEP?
|
1. clear text keys
2. Static keys make passwords easy to guess 3. One-way authentication only(AP only authenticates client) makes it easier for rogue APs to infiltrate the WLAN 4. encryption schemes are easily broken in a matter of seconds 5. Not scalable |
|
|
WEP support what forms of authentication?
|
Open and shared key
|
|
|
What is WPA?
|
Wi-Fi Protected Access
|
|
|
What are the strengths of WPA over WEP?
|
1. Has two-way authentication
2. Dynamic keys and a stronger encryption scheme through use of TKIP,"teek-kip" 3. uses 8-byte message integrity check(MIC) to protect against replay attacks, spoofing, and man-in-the middle attacks 4. Uses 802.1x or pre-shared keys(PSK) for authentication 5. Requires a passphrase vs a password, 20-30 characters recommended |
|
|
What does WPA use as an encryption scheme?
|
TKIP, "teek-kip"
|
|
|
What is TKIP?
|
Temporal Key Integrity Protocol. Provides a stronger encryption scheme for WPA.
|
|
|
What is MIC?
|
Message Integrity Check aka Michael, is 8 bytes and protects against replay attacks, spoofing, and man-in-the middle attacks, used by WPA
|
|
|
what is 802.1x?
|
Pre-shared keys(PSK) used for authentication with WPA
|
|
|
In WPA, passphrases are recommended to be how many characters?
|
20-30 characters long
|
|
|
What are the weekness with WPA?
|
1. Issues with MIC or Michael. APs will shut down their BSS if it receivies 2 consecutive packets including bad MIC, DoS attacks designed to counteract MIC will take advantage of the situation.
2. issue with PSK, if small passphrase is allowed and then intercepted, a dictionary attack can be run by an attacker, resulting in a compromised passphrase |
|
|
True or False? TKIP is backwards compatible with hardware that were created to use WEP?
|
True
|
|
|
WEP and TKIP uses what for encryption?
|
RC4 stream cipher
|
|
|
True or False? WEP protects RC4 keys vial per-packet key mixing, which results in every packet having a unique encryption key.
|
False, TKIP protects RC4 keys via per-packet key mixing, which results in every packet having a unique encryption key
|
|
|
Which modulation technique is simpler and less expensive to implement?
|
Direct Sequence Spread Spectrum(DSSS)
|
|
|
Which modulation technique has faster data rates?
|
Orthogonal Frequency Division Multiplexing(OFDM)
|
|
|
What kind of wireless uses modulation technique OFDM?
|
802.11a
|
|
|
What are the disavantages of using wireless a?
|
-easily blocked by walls;poor performance due to obstructions
-Russia do not permit this frequency |
|
|
What are the advantages of wireless a?
|
-Less likely to experience interference from other frequencies
-Faster data rates |
|
|
True/False? Wireless G uses OFDM to achieve higher data rates?
|
True
|
|
|
True/False? Wireless G uses DSSS for backward compatibility with 802.11b?
|
True
|
|
|
What are the advantages and disadvantages to wireless b?
|
Advant: better range than wireless a, not easily obstructed
Disadvant: prone to interference because many other devices use the 2.4 GHz |
|
|
True/False? Higher frequencies like wireless a requires bigger antennas?
|
False, they use smaller antennas
|
|
|
What is MIMO technology and which wireless uses this?
|
Multiple input/multiple output (MIMO) technology splits a high data-rate stream into multiple lower rate streams and broadcasts them simultaneously over the available radios and antennae, this allows for theoretical max data rate of 248 Mb/s using two streams
|
|
|
What are the 3 key organizations within the Wi-Fi allliance?
|
-ITU-R(International Telecommunications Union Radio)
-IEEE(Institute of Electrical and Electronics Engineering) -Wi-Fi |
|
|
What are the roles of
ITU-R IEEE Wi-Fi Alliance |
-ITU-R regulates allocation for RF bands
-IEEE specifies how RF is modulated to carry info -Wi-Fi Alliance ensure that vendors make interoperable devices |
|
|
Concerning CSMA/CA, what is a hidden node(or station) problem?
|
nodes transmitting simultaneously because they cannot see or sense each other because they are each at max length from their AP
|
|
|
What feature is used to resolve the hidden node problem with CSMA/CA?
|
RTS/CTS(request to send/clear to send) allows negotiations between client and AP. Medium is allocated to requestor until transmission is complete.
|
|
|
What roles does a wireless router perform?
|
The role of an AP, Switch and router
|
|
|
What is a SSID?
|
Shared Service Set Identifier is a unique identifier that clients use to distinguish between multiple wireless networks in the same vicinity.
|
|
|
True/False? Multiple AP can share the same SSID?
|
True
|
|
|
The 2.4 band is broken down to how many channels in the North America and Europe?
|
11 channels in NA
and 13 channels in Europe |
|
|
With the 2.4 band, when having 3 adjacent APs, what channels should be used?
|
1, 6, and 11 so they don't overlap each other
|
|
|
What are beacons?
|
Beacons – Frames used by the WLAN network to advertise its presence Includes SSID, supported rate, security implementations
|
|
|
What are probes?
|
Frames used by WLAN clients to find their networks
|
|
|
True/False?Beacons, frames for probing, authentication and association are being regularly broadcasted?
|
False. Beacons are regularly broadcasted but probing, authentication and association frames are only used during association and re-association process only.
|
|
|
What is the client AP association process?
|
1. Probing
2. Authentications a. Open b. Shared key authentication 3. association |
|
|
What are 3 unauthorized access(threats) to WLAN?
|
-War drivers- driving around to find an open WAP
-Hackers -Rogue AP |
|
|
What are two types of wireless attacks?
|
MITM and DOS attack.
|
|
|
Explain Denial of Service Attack and Man-in-the-middle attack?
|
DOS- attacker sends disassociate commands that cause all stations in the BSS to disconnect. When the stations disconnect, they immediately try to re-associate, which creates a burst of traffic. Attacker then repeats the process.
MITM- intercepts data tramission by comprising the AP |
|
|
How are MITM attacks defeated?
|
1. Authentication must be used.
2. Monitor the network for unexpected devices 3. Use tools like Intrusion Prevention Systems(IPS), including scanners that identify rogue AP and ad hoc networks, Radio Resource Management(RRM) which monitors the RF band for activity and AP load, APs that alert admins of unauthorized access. |
|
|
What is LEAP and what security protocol uses it?
|
Lightweight Extensible Authentication protocol is used by WEP; user credentials are not strongly protected.
|
|
|
What security method uses LEAP, PEAP and EAP-FAST?
|
WPA
|
|
|
What is PEAP and EAP-FAST?
|
PEAP - Protected EAP; is an encapsulation protocol
EAP-FAST- (Flexible Authentication via Secure Tunneling) is a protocol proposal by Cisco Systems as a replacement for LEAP |
|
|
What is 802.11i?
|
WPA2
|
|
|
What does WPA2 use as authentication and encryption?
|
Encryption: AES(Advance Encryption Standard)
Authentication: 802.11x. |
|
|
PSK or PSK2 with TKIP is the same as what?
|
WPA
|
|
|
PSK/PSK2 with AES is the same as what?
|
WPA2
|
|
|
PSK2 without encryption is the same as what?
|
WPA2
|
|
|
True/False? When you see “Personal” in a security mode, no AAA server is used. “Enterprise” in the security mode name means an AAA server and EAP authentication is used.
|
Ture
|
|
|
In solving RF interference issues, set your AP to what channel if you only had one AP?
|
Set to channel 1 or 6 since most interferences operate on channel 6.
|
