Business Data Networks & Security Ch: 4-6
If you see a username and password on a Post-It note that anyone can see on a monitor, is it hacking if you use this information to log in?
yes
You accidentally discover that you can get into other e-mail accounts after you have logged in under your account and only spend a few minutes looking at another user's mail. Is that hacking?
yes
You are concerned with the security of a site you use and run a vulnerability test against it. The test reveals a security threat. Is this hacking?
yes
Vulnerability-based attacks that occur before a patch is available are called ________ attacks.
zero-day
Understand the inverse square law for attenuation. Be able to solve a problem such as (228): If the signal strength at 10 meters is 40 milliwatts (mW), what will the strength be at 20 meters? (answer: 10 mW)
(1/r^2) -- for simple problems S2 = S1(r1/r2)^2 -- for problem given Note: r is the meters for the first and second signal
What is binary 0000 in hex?
0
How long (in milliseconds) is a clock cycle if I transmit 400 Mbps with four states?
0.000005
If you double the number of states, you can transmit ________ more bit(s) per clock cycle.
1
In large Ethernet networks, there can be ________ possible data links between two hosts.
1
CAT 5e and CAT 6 wiring can carry Ethernet traffic 100 meters up to ________.
1 Gbps
If the lowest frequency in a channel is 1.22 MHz and the highest frequency is 1.25 MHz, what is the channel bandwidth? (Use proper metric notation.) [231]
1.25 - 1.22 = 0.03 MHz or 30 kHz
What is 9 hex in binary?
1001
Two switches that are 200 m apart at a speed of 20 Gbps should be connected using ________.
10GBASE-SR with bonding
What is F hex in binary?
1111
In most encryption, keys must be at least ________ long to be considered safe.
128 bits
What is binary 1111 in hex?
15
To transmit five bits per clock cycle, you must have ________ states.
16
What is binary 0010 in hex?
2
For each, compare channel bandwidth and the number of possible channels. [250]
2.4 802.11g use 20 MHz and 3 Channels. 802.11n Single Band has 20 MHz and 3 Channels 802.11n Dual Band uses 40 MHz has 3 in 2.4 GHz , 12 (US) in the 5 GHz 802.11ac has 80 MHz and 160 MHz uses 6 in 80 MHz and 3 Channels in 160 MHz 802.11ad uses 60 MHz and 3 Channels in the US & 4 in Europe. , 5, and 60 GHz band
How many non-overlapping 20 MHz channels does the 2.4 GHz band support? [235-237]
2.4 GHz, three possible non-overlapping 20 MHz 802.11 channels, which are centered at Channels 1, 6, and 11.
In what two unlicensed bands does 802.11 operate? [235-237]
2.4 and 5 GHz
What frequency band or bands do 802.11g, 802.11n single band, 802.11n dual band, 802.11ac, and 802.11 ad use? [250]
2.4, 5, 60 GHz band
Convert 3.4 MHz to a number without a metric prefix. [226]
3400000 Hz
A system with 16 states can transmit ________ bits per clock cycle
4
If a physical link can use either 4-pair UTP, multimode fiber, or single-mode fiber, which should I use?
4-pair UTP
What type of copper wiring is widely used in Ethernet?
4-pair UTP
Which core diameter is used in multimode fiber.
50 microns
At what range of frequencies do most wireless systems operate? [226]
500 megahertz 10 gigahertz
How many wires are there is a UTP Ethernet cord?
8
The 802.11ac Wi-Fi standard uses 256 states. How many bits can it send per clock cycle?
8
To transmit three bits per clock cycle, you must have ________ states.
8
What 802 working group creates 802.11 standards? [225]
802.11 Working Group
Which can bring gigabit speeds to clients? [247-249]
802.11ac & 802.11ad
What is the maximum rated speed for each standard? [247-249]
802.11g = 54 Mbps 802.11n Single Band = 100 to 600 Mbps 802.11n Dual Band = 100 to 600 Mbps 802.11ac = 433 Mbps to 6.9 Gbps 802.11ad = 7 Gbps
What is backward compatibility? [254]
802.11g access point. In the same way, an 802.11n access point must be able to work with an older 802.11g access point. Of course, when an 802.11n device works with an 802.11g device, the transmission can take place only at 802.11g speeds. The 802.11n device must drop back to 802.11g operation. This Panko, Raymond; Panko, Julia (2012-10-09). Business Data Networks and Security (9th Edition) (Page 254). Prentice Hall. Kindle Edition.
Of the four 802.11 transmission standards summarized in this section, which are full standards, and which are only draft standards?
802.11g and 802.11n are full standards 802.11ac and 802.11ad are still draft standards.
Compare maximum speeds for 802.11g and 802.11n and the maximum distances at which each standard can provide these speeds. [247-249]
802.11g, the maximum distance and speed are 30 m and 54 Mbps. 802.11n, distance and speed are much longer and faster at 70 m and 100-600 Mbps respectively.
To prevent an unauthorized user from sending supervisory commands to switches, companies use ________.
802.1AE
To prevent anyone from simply walking up to a corporate switch and plugging their computer into its Ethernet port, companies can use ________.
802.1X
What 802 Working Group creates Ethernet standards?
802.3
Which light wavelength dominates in LANs?
850 nm
Which of the following is used most often in LANs for fiber transmission links?
850 nm multimode fiber
What is channel bandwidth? [231]
A channel also has a bandwidth. For instance, if the lowest frequency of an FM channel is 89.0 MHz and the highest frequency is 89.2 MHz, then the channel bandwidth is 0.2 MHz (200 kHz).
How can firms provide WLAN coverage throughout a large building? [225]
A firm can strategically place wireless access points judiciously throughout a building. In essence, the firm is creating a large 802.11 WLAN "cloud" .
What is a handoff in 802.11? [243]
A handoff is when a user moves to a closer access point.
________ is a program that can capture passwords as you enter them.
A keystroke logger
________ is a flaw in a program that permits a specific attack or set of attacks.
A vulnerability
________ is the general name for a security flaw in a program.
A vulnerability
________ attacks typically extend over a period of months.
APT
What is a clear line-of-sight limitation? [234]
Absorption and shadow zone propagation problems are large. In addition, demand for channels and service bands in the golden zone is increasing rapidly.
________ links connect users to workgroup switches.
Access
Besides moving packets between wireless clients and the Ethernet network, what other control functions do access points have? [242]
Access points also control hosts as wells as assigning transmission power levels to hosts within its range and other supervisory chores.
What devices forward frames in a mesh network? [256]
Access points or wireless hosts
What is the purpose of the 802.11r standard? [243]
Access points to contact one another when it deals with roaming.
How does Wi-Fi Direct differ from the traditional way in which two wireless hosts communicate?[255]
Adhoc connection, no access point need and its simpler.
What is an ESS? (Do not just spell out the abbreviations.) [243]
An extended service set (ESS) is a group of BSSs that are connected to the same distribution system (network) and have the same SSID.
What factors influence individual throughput, given a certain level of aggregate throughput? [253]
Another consideration is that speed is highest when a user is very near an access point. As the user moves away, speed falls. The problem is that at maximum transmission speed, there must be almost perfect propagation characteristics. As a user moves away from an access point, signal strength falls, errors There are many other factors that will reduce individual throughput. For example, there are still some wireless devices that use the old 802.11b standard, which only has a rated speed of 11 Mbps. \
________ look at ________, while ________ mostly look at ________.
Antivirus programs; files; firewalls; packets
What is the advantage of using unlicensed bands? [235]
Any wireless host can be turned on or moved around without the need for any government approval.
Given their relative bandwidths, about how many times as much data is sent per second in television than in AM radio? (The information to answer this question is in the text.) [231].
Approximately 600 times more data are sent per second in television as opposed to AM radio.
Why does transmission speed drop as a computer moves farther from an access point? [253]
As distance increase, attenuation increases therefore the wireless access point have to switch to a more reliable frequency which results in slower speeds.
Which attenuates more rapidly with distance—signals sent through wired media or radio signals?
Attenuation with radio signal rapidly increases as distance increases
What is a BSS? (Do not just spell out the acronym.) [242]
Basic service set (BSS) A basic service set (BSS) consists of an access point and the set of hosts it serves
OFDM Describe it. [240]
Broadband channels are dived into smaller sub channels called carriers. Parts of each frame are transmitted in each subcarrier. OFDM sends data redundantly across the subcarriers, so if there is impairment in one or even a few subcarriers, all of the data usually will get through.
How does MIMO work? [251]
By having the host or access point send two or more spatial streams (radio signals) in the same channel between tow or more different antennas on access point and wireless hosts.
Write the Shannon Equation. List what each letter is in the equation. [231]
C = B [Log^2 (1+S/N)] C = Maximum possible transmission speed in the channel (bps) B = Bandwidth (Hz) S/N = Signal-to-noise ratio measured as the power ratio, not as decibels Note that doubling the bandwidth doubles the maximum possible transmission speed Multiplying the bandwidth by X multiplies the maximum possible speed by X Wide bandwidth is the key to fast transmission Increasing S/N helps slightly, but usually cannot be done to any significant extent
A) that passwords be easy to remember B) that passwords be long phrases instead of being about 8-12 characters long C) both A and B D) neither A nor B
C) both A and B
Antivirus programs are designed to detect ________. A) viruses B) worms C) both A and B D) neither A nor B
C) both A and B
Employees often attack ________. A) for revenge B) for money C) both A and B D) neither A nor B
C) both A and B
Ethernet standards are specified at the ________ layer. A) physical B) data link C) both A and B D) neither A nor B
C) both A and B
In terms of security thinking, "insiders" include ________. A) employees B) many contractors working for the company C) both A and B D) neither A nor B
C) both A and B
Physical layer standards govern ________. A) signaling B) physical connectors C) both A and B D) neither A nor B
C) both A and B
RSTP ________. A) can increase reliability B) was created to break accidental loops C) both A and B D) neither A nor B
C) both A and B
The messages of VPNs ________. A) share the same transmission lines used by other VPNs B) are encrypted C) both A and B D) neither A nor B
C) both A and B
Viruses and worms propagate through ________. A) social engineering B) exploiting vulnerabilities C) both A and B D) neither A nor B
C) both A and B
When a firewall identifies an attack packet, it ________. A) discards the packet B) copies information about the packet into a log file C) both A and B D) neither A nor B
C) both A and B
Which UTP quality levels can send signals at 10 gigabits per second? A) category 6 B) category 6A C) both A and B D) neither A nor B
C) both A and B
Which form of authentication depends on the supplicant proving that she knows something only the true party should know? A) reusable password authentication B) iris scanning C) both A and B D) neither A nor B
C) both A and B
Which of the following meets the definition of hacking? A) to intentionally use a computer resource without authorization B) to intentionally use a computer on which you have an account but use it for unauthorized purposes C) both A and B D) neither A nor B
C) both A and B
Who mounts APTs today? A) national governments B) cybercriminals C) both A and B D) neither A nor B
C) both A and B
The supplicant is ________. A) the true party B) an impostor C) either A or B D) neither A nor B
C) either A or B
What is a collision? [244] Why is it bad? [244]
Channel Sharing The access point and all the hosts it serves transmit in a single channel. If two devices transmit at the same time, their signals will collide, becoming unreadable. (If two devices transmit in the same channel at the same time, their signals will interfere with each other.)
What feature do all access points in an ESS share? [243]
Connected to the same distribution system (network) and have the same SSID.
List some sources of EMI[229]
Cordless telephones, microwaves and devices near the wireless network
Secured packets typically receive ________. A) confidentiality B) authentication C) message integrity D) all of the above
D) all of the above
EUI-48 addresses in expressed in hexadecimal notation if used by ________. A) switches B) routers C) both A and B D) neither A nor B
D) neither A nor B
Ethernet standards are specified at the ________ layer. A) Internet B) transport C) both A and B D) neither A nor B
D) neither A nor B
Trojan horses can spread by ________. A) e-mailing themselves to victim computers B) directly propagating to victim computers C) both A and B D) neither A nor B
D) neither A nor B
Which of the following letters may appear in EUI-48 addresses? A) D B) H C) both A and B D) neither A nor B
D) neither A nor B
Four-pair UTP uses ________ connectors. A) universal B) binary C) ST or SC D) none of the above
D) none of the above
If a packet is highly suspicious but not a provable attack packet, an ________ may drop it. A) SPI firewall B) IDS C) NGFW D) none of the above
D) none of the above
In distributed DoS attacks, the attacker sends messages directly to ________. A) bots B) the intended victim of the DoS attack C) a DOS server D) none of the above
D) none of the above
The digital certificate provides the ________. A) private key of the supplicant B) private key of the true party C) public key of the supplicant D) none of the above
D) none of the above
How did the Target attackers obtain the stolen information? A) Directly from the POS terminals B) From the vendor service server C) From the POS software download server D) none of the above.
D) none of the above.
What business application will gigabit transmission speed make feasible to do wirelessly?
Data backup, sharing data, and syncing data
________ describe light entering a fiber's core at different angles.
Different modes
How can access points communicate with each other? [243]
Distribution system.
________ is the official name for Ethernet addresses.
EUI-48
The ARP cache gives the ________ of a router the host will send a packet to.
EUI-48 address
After an ARP cache poisoning attack, the ARP cache gives the ________.
EUI-48 address of the router the MITM attacker
A switch knows the entire data link between the source and destination hosts.
False
All Ethernet switches are manageable.
False
Hacking is defined as using a computer resource without authorization or in excess of authorization.
False
The switch knows the type of device it is forwarding a frame to.
False
Is wireless radio transmission usually expressed in terms of wavelength or frequency? [226]
Frequency
Distinguish among the frequency spectrum, service bands, and channels. [230]
Frequency spectrum all possible frequencies from zero hertz to infinity. Service bands contiguous spectrum ranges within a frequency spectrum. Channels are subdivided service brands with smaller frequency ranges
Beamforming What two benefits can it bring? [252]
Gives more effective power, stronger signal to each wireless host and greater propagation distance.
Why is the golden zone important? [234]
Golden zone frequencies are high enough for there to be large total bandwidth At higher frequencies, there is more available bandwidth Golden zone frequencies are low enough to allow fairly good propagation characteristics At lower frequencies, signals propagate better
What is the main benefit of MIMO? What is its other benefit? [251]
Greater transmission speed & greater transmission distance.
How does the presence of a distant station harm all users of an access point? [253]
Hosts connected with an access point are some that are farther away, throughput will fall because signal have to travel longer distance and will take longer to send and receive packets, and this time will be take away from other users.
802.11s standard Panko, Raymond; Panko, Julia (2012-10-09). Business Data Networks and Security (9th Edition) (Page 256). Prentice Hall. Kindle Edition.
How does Wi-Fi Direct differ from the traditional way in which two wireless hosts communicate?[255] Adhoc connection, no access point need and its simpler. b) Can a large Wi-Fi network operate without an Ethernet switched backbone? [256] yes c) What technology allows this? [256] adhoc d) What is the current 802.11 standard for this technology? [256]
Which of the following is the most frustrating to use?
IDSs
What organization (most specifically) creates Ethernet standards?
IEEE
Who are the most dangerous types of employees?
IT security employees
Why is the number of non-overlapping channels that can be used important? [235-237]
If nearby access points operate in the same channel, their signals will interfere with each other unless the access points are far apart. This interference is called co-channel interference.
Ethernet addresses were formerly called ________ addresses.
MAC
Does media access control limit the actions of wireless hosts, the access point, or both? [244]
MAC limits both the actions of wireless hosts and the access point.
________ is the most frequent type of company attack.
Malware
What happens to the maximum possible propagation speed in a channel if the bandwidth is tripled while the signal-to-noise ratio remains the same? [231]
Maximum possible transmission is trippled
What information does C give you? [231]
Maximum possible transmission speed in the channel (bps)
What is the purpose of media access control? [244]
Media access control (MAC) methods govern when hosts and access points may transmit so that collisions can be avoided. The access point and all of the wireless hosts it serves transmit and receive in a single channel. When a host or the access point transmits, all other devices must wait.
________ occurs when the light energies of two pulses arrive at the far end at overlapping times.
Modal dispersion
What spread spectrum transmission method is used for the most recent 802.11 standards? [240]
Most recent 802.11 standards use Orthogonal Frequency Division Multiplexing (OFDM)
What is the most serious propagation problem in WLANs? [229]
Multipath interference may cause the signal to range from strong to nonexistent within a few centimeters
Distinguish between MIMO and multiuser MIMO. [252]
Multiuser MIMO is the possibility of simultaneously transmission in a single channel by multiple devices that are using a single access point as oppose to just one on MIMO. Beamforming can also bring multiuser MIMO, which is the possibility of simultaneous transmission in a single channel by multiple devices that are using a single access point. The 802.11n standard specified multiuser MIMO, but it did not specify a single multiuser MIMO technology. This led to a great deal of market confusion, and multiuser MIMO did not become popular with 802.11n. With 802.11ac, the Technical Group 802.11ac avoided market confusion by specifying a single multiuser MIMO technique. Beamforming is likely to be common in 802.11ac products.
Which type of firewall filtering collects streams of packets to analyze them as a group?
NGFW
Which type of firewall filtering looks at application-layer content?
NGFW
Which type of firewall is more expensive per packet handled?
NGFW
In normal radio operation, how does channel bandwidth usually relate to the bandwidth required to transmit a data stream of a given speed? [239]
Normal Transmission versus Spread Spectrum Transmission (See Figure 6-16) Normal transmission uses only the channel bandwidth required by your signaling speed Spread spectrum transmission uses channels much wider than signaling speed requires
What spread spectrum method do all four standards use as their main method?
OFDM
What is the quality designator for multimode optical fiber?
OM
________ fiber is being sold today.
OM4
When a device designed to use a newer standard must work with a device that only uses an older standard, what standard do they use to communicate? [254]
Older standard
What type of antenna normally is used in WLANs? Why? [227]
Omnidirectional antennas are normally used in WLANs, because transmission of signal is equally strong in all direction, transmission signal spread in all three dimensions and receives incoming signal well from all direction. They are best for short distance.
Distinguish between omnidirectional and dish antennas in terms of operation. [227]
Omnidirectional can transmit three-dimensional signal transmission but short distance while dish antennas can point transmission of signals in one direction. Signals can also travel longer distances because of focusability.
What is a hertz? [226]
One cycle per second
At what layers do wireless networks operate? [224]
Physical Link and Data Link Layers.
Distinguish between rated speed, aggregate throughput, and individual throughput. [253]
RATED SPEED VERSUS THROUGHPUT Rated speed is the number of bits that the host or access point will transmit per second. access point throughput is aggregate throughput, which is shared by all users of an access point. Suppose that the aggregate throughput is 100 Mbps per second and there are 10 users of an access point. then individual throughput would be about 10 Mbps (actually somewhat less because of time lost in turn-taking). Of course, it would be rare for all stations to transmit simultaneously. However, even if three are sending and receiving simultaneously, the individual throughput they experience would be about 30 Mbps. Access point throughput is aggregate throughput This must be shared by all stations currently sending or receiving Individual throughput can be much lower than aggregate throughput
4-pair UTP terminates in a(n) ________ connector.
RJ-45
Why is multipath interference very sensitive to location? [229]
Radio waves tend to bounce off walls, floors, and other object therefore direct signal and out of bounced signal may arrive out of phase when they arrive to the receiver because they travel different distances. The signals then cancels out.
To manage their Ethernet networks, companies rely on ________.
SNMP
What three issues must be overcome to make mesh networking acceptable to corporations? [256]
Self-organizing, overloading near the geographical center of the mesh, and securities
In radio, how can you send multiple signals without the signals interfering with one another? [230]
Service bands are subdivided into smaller frequency ranges called channels. A different signal can be sent in each channel because signals in different channels do not interfere with one another. This is why you can receive different television channels successfully.
What propagation problems become worse as frequency increases? [230]
Shadow zone propagation problems tend to grow worse with frequency
Under what circumstances would you use an omnidirectional antenna? [227]
Short distances, three dimensional signal transmissions.
) If spectrum scarcity becomes a problem, how will that affect users? [255]
Slower growth and cost for transmission will rise
Why must wireless devices know the access point's SSID? [243]
So wireless devices knows how to associate the access point.
Why may spectrum scarcity be a problem?
Spectrum scarcity may be a problem because unless more efficient wireless transmission methods emerge very rapidly, spectrum capacity will place limits on demand growth.
Compare the range of rated speeds possible 802.11g with 40 MHz channels and 802.11ac. [251]
Speeds for 802.11 with 40 MHz channels is 300 Mbps. 802.11ac doubles the possible spatial streams to eight. This creates a large number of possible rated speeds of 433 Mbps, 867 Mbps and 1.3 Gbps.
Does a signal usually travel at a single frequency, or does it spread over a range of frequencies? [231]
Spread over a range of frequencies called bandwidth.
Is spread spectrum transmission done for security reasons in commercial WLANs? [239]
Spread spectrum transmission is not done for security reasons in commercial WLANs.
What is the benefit of spread spectrum transmission for business communication? [238]
Spread spectrum transmission is transmission that uses far wider channels than transmission speed requires therefore reducing propagation problems and channel interference.
How does this change in spread spectrum transmission? [239]
Spread spectrum transmission is transmission that uses far wider channels than transmission speed requires.
________ is the general name for malware on a user's PC that collects sensitive information and sends this information to an attacker.
Spyware
________ is the dominant firewall filtering method used on main border firewalls today.
Stateful packet inspection
What is white space, and why is using it attractive? [255]
The FCC is now considering how equipment can use empty channels (known as white space) on an opportunistic basis. This can provide more spectrum capacity for WLAN operation, cellular and similar service, or both. Regulatory agencies around the world are now considering how to allocate white space. Panko, Raymond; Panko, Julia (2012-10-09). Business Data Networks and Security (9th Edition) (Page 255). Prentice Hall. Kindle Edition.
What is the relationship between handoffs and roaming in WLANs? [243]
The ability to use handoff ins is called roaming in WLANs
Does the access point have an SSID? [243]
The access point in a BSS has an identifier called the service set identifier (SSID). Wireless hosts must know the SSID to associate with the access point.
For consumers who suffered credit card fraud because of the Target breach and acted quickly, which of the following is true?
The credit card companies did not charge them for fraudulent purchasers.
What is the golden zone in commercial mobile radio transmission? [234]
The golden zone for commercial mobile services is 500 MHz to 10 GHz.
Why is large channel bandwidth desirable? [231]
The maximum possible speed is directly proportional to bandwidth, so if you double the bandwidth, you can potentially transmit up to twice as fast.
In the figure, what is the distribution system? [241]
The network to which access point connect (Wired Ethernet LAN).
Why can two products that comply with the same standard have different performance? [257]
The number of hardware varies between manufacturer such as number of antenna and processor used.
Does the 2.4 GHz band or the 5 GHz band allow longer propagation distances for a given level of power? Justify your answer. [235-237]
The power required for 2.4 Ghz band is lower allowing it to transmit longer distances however, 5 Ghz bands use higher frequencies therefore higher absorptive attenuation.
What is the downside of wider channel bandwidth? [250]
The wider channel bandwidth the fewer channels.
In general, what should an employer do whenever an employee leaves the firm?
Their accounts should be disabled instantly
Why are employees especially dangerous?
They are trusted.
What other types of system do we call broadband? [233]
Transmission systems that are very fast are usually called broadband systems even when they do not use channels.
What other types of system do we call broadband? [233]
Transmission systems: They are very fast are usually called broadband systems even when they do not use channels.
What is the advantage of having three antennas rather than two on an access point? [257]
Transmit three spatial streams allowing for a faster data transfer and better reliability.
Malware programs that masquerade as system files are called ________.
Trojan horses
Biometrics, and other new authentication methods, are being created with the goal of getting rid of reusable passwords.
True
In this book, we use the terms Ethernet and 802.3 interchangeably.
True
________ links connect switches to other switches.
Trunk
What is the disadvantage? [235]
Users must be able to tolerate interference from others
Which of the following provides security in Ethernet?
VLANs
Do WLANs today use licensed or unlicensed bands? [235]
WLANs use unlicensed bands
SSL/TLS is used for ________.
Web applications
Which offers more reliable transmission characteristics—UTP or radio transmission? [228]
Which offers more reliable transmission characteristics—UTP or radio transmission? [228]
What are the benefits and problems of transmission in the 60 GHz band? [250]
Winder channels but less channels available to use
Why is a wired LAN usually still needed if you have a wireless LAN? [241]
Wireless LANs is typically used to connect a small number of mobile devices to a large wired LAN typically Ethernet LAN because the servers and Internet access routers that mobile hosts need to use usually are on the wired LAN
Why do wireless clients need access to the wired Ethernet LAN? [225]
Wireless clients to access network resources it needs to be connect to wireless access point, which is usually connected to Ethernet LAN where resources such as Internet access router are usually located. 802.11 WLANs today are also primarily supplement wired LANs.
Are wireless network standards OSI standards or TCP/IP standards? Explain. [224]
Wireless network are also single network, which require physical and data link layer standards so they are also OSI standards.
In unlicensed bands, what type of transmission method is required by regulators [238]
You are required by law to use spread spectrum transmission in unlicensed bands Spread spectrum transmission reduces propagation problems Especially multipath interference Spread spectrum transmission is NOT used for security in WLANs Normal Transmission versus Spread Spectrum Transmission
ARP cache poisoning is ________.
a man-in-the middle attack
In digital signaling, there is (are) ________ state(s).
a small number of
The strength of a wave is its ________.
amplitude
List the elements in a typical 802.11 LAN today. [241]
an 802.11 wireless LAN typically is used to connect a small number of mobile devices to a large wired LAN— typically, an Ethernet LAN—because the servers and Internet access routers that mobile hosts need to use usually are on the wired LAN.
A spear phishing attack is usually aimed at ________.
an individual
Authentication should generally be ________.
appropriate for a specific resource
Electronic signatures provide message-by-message ________.
authentication
Requiring someone prove his or her identity is ________.
authentication
In antivirus filtering, the best ways to filter currently use ________.
behavioral detection
Using bodily measurements for authentication is ________.
biometrics
In a DDoS attack, a ________ sends messages directly to the victim.
bot
Attack programs that can be remotely controlled by an attacker are ________.
bots
Which of the following can be upgraded after it is installed on a victim computer (choose the most specific answer)?
bots
What do we call a system whose channels have large bandwidth? [233]
broadband channels (fast)
NGFWs ________.
can implement different rules for different applications
The Target attackers sold stolen card information to ________.
card shops
What type of attacker are most attackers today?
career criminals
Which UTP quality levels are needed to send signals 100 meters at 10 gigabits per second?
category 6A
In digital certificate authentication, the verifier gets the key it needs directly from the ________.
certificate authority
A specific encryption method is called a ________.
cipher
Using encryption, you make it impossible for attackers to read your messages even if they intercept them. This is ________.
confidentiality
In SPI firewalls, ACLs are used for packets in the ________ state.
connection-opening
In optical fiber, light travels through the ________.
core
Trunk links connect switches to ________ switches.
core
What type of switch connects switches to other switches?
core switches
In authentication, ________ are the general name for proofs of identity.
credentials
Which of the following were able to recoup most of the money they lost from Target?
credit card companies
The path a message takes from the source host to the destination device in an Ethernet network is a ________.
data link
In an SPI firewall, all rules except the last will permit the connection. The last will ________.
deny the connection
Which of the following can spread very rapidly?
directly-propagating viruses
Why is wider channel bandwidth good? [250]
doubling channel bandwidth doubles transmission speed. However, service bands have limited total bandwidth, so wider channels means fewer channels. ]
When a packet that is not part of an ongoing connection and that does not attempt to open a connection arrives at a stateful inspection firewall, the firewall ________.
drops the packet
The Target attackers probably first broke into Target using the credentials of a(n) ________.
employee in a firm outside Target
NIST guidelines for reusable passwords permit ________.
entirely lower-case passwords
Firewall log files should be read ________.
every day
To span the distance between two switches, why is adding an intermediate switch not an attractive choice?
expense
Advanced persistent threats are ________.
extremely dangerous for the victim
Optical fiber cords use two strands ________.
for full-duplex transmission
Ethernet messages are ________.
frames
The ability to transmit in two directions simultaneously is ________.
full-duplex communication
Optical fiber cords typically have two fiber strands. This is done to allow ________.
full-duplex operation
What is beamforming? [252]
having multiple antennas and changing the phase of waves coming from different antennas, an access point can focus signals toward individual hosts instead of broadcasting them,]
Ethernet has reliability issues because of its ________.
hierarchical organization
In Ethernet, switches are organized in a ________.
hierarchy
In which type of attack does the attacker gather extensive sensitive personal information about its victim?
identity theft
Which is more harmful to the victim?
identity theft
If the signal strength from an omnidirectional radio source is 8 mW at 30 meters, how strong will it be at 120 meters, ignoring absorptive attenuation? Show your work. [228]
if S2 = S1 * (r1/ r2) 2 Then S2 = 8 mW* (30 meters /120 meters) 2 S2 = 8 mW* (1/4) 2 S2 = 8 mW* (1/16) S2 = 1/2 mw
How are shadow zones (dead spots) created? [229]
if there is a large or dense object (e.g., a brick wall), blocking the direct path between the sender and the receiver, the receiver may be in a ___________ (d___ spot), where the receiver cannot get the signal.
Users typically can eliminate a vulnerability in one of their programs by ________.
installing a patch
A firewall will drop a packet if it ________.
is a definite attack packet
Using RSTP to provide backup links in Ethernet ________.
is challenging
Using SSL/TLS for Web applications is attractive because SSL/TLS ________.
is essentially free to use
Facial recognition is controversial because ________.
it can be used surreptitiously
Fingerprint recognition is generally acceptable for ________.
laptops
Digital certificate authentication fails if the supplicant ________.
learns the true party's private key
Compared to NGFWs, IDSs ________.
look for different threats
Ethernet became the dominant LAN technology because of ________.
low cost
SPI firewalls are attractive because of their ________.
low cost
Stateful packet inspection firewalls are attractive because of their ________.
low cost for a given traffic volume
The general term for evil software is ________.
malware
Electronic signatures also provide ________ in addition to authentication.
message integrity
Modal dispersion limits transmission distance in ________.
multimode fiber
Which of the following is used most often in LANs for fiber transmission links?
multimode fiber
channels with small bandwidths
narrowbands (slow)
Cyberwar attacks are made by ________.
national governments
In general, what type of attackers do the most damage?
national governments
You click on a link expecting to go to a legitimate website but are directed to a website that contains information you are not authorized to see. You exit without looking around. is that hacking?
no
A local area network operates ________.
on a customer premises
In 4-pair UTP, what is twisted?
pairs of wires
How will a stateful packet inspection (SPI) firewall handle a packet containing a TCP segment that contains an acknowledgement?
pass it if it is part of an approved connection
When a packet that is part of an ongoing connection arrives at a stateful inspection firewall, the firewall usually ________.
passes the packet
Pieces of code that are executed after the virus or worm has spread are called ________.
payloads
At what layer is the 100BASE-TX standard?
physical
Ethernet standards are specified at the ________ layer.
physical
UTP and fiber distance limits are for ________.
physical links
SPI firewalls are being replaced in large part because they are limited in their ability to detect ________.
port spoofing
Iris scanning is attractive because of its ________.
precision
The two tag frames provide information about ________.
priority
UTP categories rate the ________ of UTP cabling.
quality
What problem limits transmission distance in 4-pair UTP?
radiation
In a ________ attack, the attacker encrypts some or all of the victim's hard drive.
ransom
DoS attacks attempt to ________.
reduce the availability of a computer
Having only a single possible path between devices ________.
reduces switching cost
Which of the following probably suffered the most financial damage from the Target breach?
retailers
In ________ thinking, the opponent is primarily an intelligent attacker.
security
The PAD field is added by the ________ if the frame is too short without it.
sender
What is an SSID? (Do not just spell out the acronym.) [243]
service set identifier (SSID). (Note that the term basic is not in the name.) Wireless hosts must know the SSID to associate with the access point.
For what specific purpose were the 2.5GBASE-T and 5GBASE-T standards developed?
serving access points
Traditionally, we have told users that passwords ________.
should have a mix of characters (uppercase and lowercase letters, digits, other keyboard characters)
For sensitive assets, reusable passwords ________.
should not be used
Physical layer standards govern ________.
signaling
If you can span the distance between two switches with either a single optical fiber link or two UTP lengths with an intermediate switch, which should you choose?
single optical fiber link
Fiber that has a core diameter of 8.3 microns is ________.
single-mode fiber
The longest transmission distances are possible with ________.
single-mode fiber
What kind of attack is most likely to succeed against a system with no technological vulnerabilities?
social engineering
The main benefit of parallel transmission over serial transmission is ________.
speed
In authentication, the ________ is the party trying to prove his or her identity.
supplicant
Ethernet forwarding devices are ________.
switches
For reusable passwords, NIST now recommends ________.
that passwords be easy to remember
How many non-overlapping 20 MHz channels does the 5 GHz band support? [235-237]
the 5 GHz band provides between 11 and 24 non-overlapping 20 MHz channels, depending on the frequencies allocated to unlicensed operation in a country.
In encryption, what must be kept secret?
the key
In digital certificate authentication, the supplicant encrypts the challenge message with ________.
the supplicant's private key
The supplicant claims to be ________.
the true party
In digital certificate authentication, the verifier decrypts the challenge message with ________.
the true party's public key
When a user attempts to plug into an Ethernet switch protected by 802.1X, ________.
the user will be required to authenticate himself or herself
850 nm multimode fiber is used in LANs ________.
to keep cost low
Signal state is held constant in a clock cycle ________.
to make it easier for the receiver to sample the state
In binary signaling, there is (are) ________ state(s).
two
A debit card is secure because it requires two credentials for authentication-the card itself and a PIN. This is called ________.
two-factor authentication
Which of the following attach themselves to other programs?
viruses
The distance between two corresponding points in adjacent cycles is the ________.
wavelength
What type of switch connects users to the network?
workgroup switches
Which of the following sometimes uses direct propagation between computers?
worms
________ are full programs.
worms
