1. Which of the following is a form of DoS attack?
a) Vulnerability attack
b) Bandwidth flooding
c) Connection flooding
d) All of the mentioned
Explanation: In a DoS attack, the attacker won’t let the victims access the network by using a certain method that ensures that an essential network resource is unavailable to the victim. In vulnerability attack, the attacker exploits any obvious vulnerable entity in the network to deny the victim access into the network. In bandwidth flooding, the attacker floods the victim with a huge flow of packets and uses up all the bandwidth. In connection flooding, the attacker floods the victim network with a huge number of connections, so that, no other machine can connect to it.
2. The DoS attack, in which the attacker establishes a large number of half-open or fully open TCP connections at the target host is ________
a) Vulnerability attack
b) Bandwidth flooding
c) Connection flooding
d) UDP flooding
Explanation: In Vulnerability attack, the attacker exploits the vulnerable control points of the network to deny access to the victims. In Bandwidth flooding, the attacker intentionally uses up all the bandwidth by flooding the victim with a deluge of packets and makes sure that the victim can’t use any bandwidth. In UDP flooding, too many UDP packets are sent by the attacker to the victim at random ports.
3. The DoS attack, in which the attacker sends deluge of packets to the targeted host is ________
a) Vulnerability attack
b) Bandwidth flooding
c) Connection flooding
d) UDP flooding
Explanation: In Bandwidth flooding, the attacker floods the victim machine with a deluge of packets to make sure that no bandwidth is available. The victim then cannot utilize the complete bandwidth to perform its operation.
4. Packet sniffers involve ____________
a) Active receiver
b) Passive receiver
c) Legal receiver
d) Partially-active receiver
Explanation: The function of packet sniffers is to just silently receive the packets flowing in the channel. If they inject any packets into the channel, they might alert the other users about the intrusion.
5. Sniffers can be prevented by using _______________
a) Wired environment
b) WiFi
c) Ethernet LAN
d) Switched network
Explanation: Switches make sure that the packet is sent to the intended receiver and no one else, thus preventing Sniffers to perform their function. Intelligent switches are hence used preferably for the network.
6. Firewalls are often configured to block ___________
a) UDP traffic
b) TCP traffic
c) Sensitive traffic
d) Best-effort traffic
Explanation: UDP is more vulnerable to attacks, so firewalls are often configured to block suspicious UDP traffic.
7. In a network, If P is the only packet being transmitted and there was no earlier transmission, which of the following delays could be zero?
a) Propagation delay
b) Queuing delay
c) Transmission delay
d) Processing delay
Explanation: Since there is no other packet to be transmitted, there is no need for a queue. Therefore, the delay caused due to the queuing would be none i.e. 0.
8. A local telephone network is an example of a _______ network.
a) Packet switched
b) Circuit switched
c) Bit switched
d) Line switched
Explanation: Circuit switching is connection oriented switching technique, whereas in the case of packet switching, it is connectionless. Circuit switching is implemented in the Physical layer, whereas packet switching is implemented in the Network layer. Internet too is based on the concept of circuit switching.
9. Most packet switches use this principle ____________
a) Stop and wait
b) Store and forward
c) Store and wait
d) Stop and forward
Explanation: The packet switch will not transmit the first bit to outbound link until it receives the entire packet. If the entire packet is not received and the time-out period expires, the packet switch will inform the sender to resend the part of packet or the entire packet based on the algorithm being used.
10. If there are N routers from source to destination, the total end to end delay in sending packet P(L-> number of bits in the packet R-> transmission rate) is equal to ______________
a) N
b) (N*L)/R
c) (2N*L)/R
d) L/R
Explanation: The equation to find the end to end delay when no. of bits, transmission rate and no. of routers is given by (N*L)/R. The total end to end delay, that is, nodal delay is the sum of all, the processing delay, queuing delay, transmission delay and propagation delay.
Why Computer Network ?
Diving into the Jungle: Understanding Network Attacks
Ever felt the shivers thinking about someone snooping into your private data? Well, you're not alone. In our cyber jungle, these digital bandits come in various shapes and sizes, armed with the deadliest weapon - malicious intent.
Phishing Expeditions: Hook, Line, and Cyber Sinker
A crafty angler luring you with a shiny bait, only this bait is an email or message. Click, and you're in their net! Phishing attacks are like the chameleons of the jungle - camouflaged and ready to strike.
Denial-of-Service (DoS) Stampede: Overwhelmed and Outnumbered
Ever had a gazillion ants invade your picnic? That's a bit like a DoS attack, where the network is swarmed, overwhelmed, and rendered useless. It's like a stampede, and your poor server is the watering hole.
Trojan Horses: Sneaky Stowaways in the Digital World
Beware of Greeks bearing gifts, especially if they're digital! Trojans are the spies of the cyber realm, pretending to be something they're not. Once inside, they wreak havoc. It's like inviting a masked bandit to a costume party.
Firewall Fortress: Guarding the Castle Walls
A good firewall is like a force field for your digital kingdom. It filters out the bad stuff, allowing only the rightful data to enter. Imagine it as the moat around your cyber castle.
Conclusion: Navigating the Cyber Wilderness
So, fellow cyber travelers, that's a wrap on our jungle adventure. Remember, the cyber wild is vast, but armed with knowledge, you can swing through the vines of network attacks like a digital Tarzan. Stay safe, stay savvy, and may your network always be hack-proof!