Computer Knowledge

Computer Networks

2,614 Questions

Computer networks involve the architecture, protocols, and security measures used for digital communication. This collection covers OSI model layers, IP addressing, data transmission, and cryptographic standards. These concepts are vital for the computer knowledge sections of banking and government exams.

OSI model layersNetwork protocolsIP subnet maskingData encryption standardsServer configurationsNetwork commands

Computer Networks Questions

Multiple choice

Which statement about standard ACLs is true?

  1. Standard ACLS must be numbered and cannot be named.

  2. They should be placed as close to the destination as possible.

  3. They can filter based on source and destination address as well as on source and destination port.

  4. When applied to an outbound interface, incoming packets are processed before they are routed to the outbound interface.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Standard ACLs filter traffic based only on the source IP address, not destination address or ports. Because they're limited, best practice is to place them as close to the destination as possible to avoid blocking legitimate traffic from multiple sources. Extended ACLs, which can filter based on source and destination addresses/ports, should be placed close to the source. Standard ACLs can be either numbered or named, contrary to option A.

Multiple choice

An administrator is configuring a dual stack router with IPv6 and IPv4 using RIPng. The administrator receives an error message when trying to enter the IPv4 routes into RIPng. What is the cause of the problem?

  1. When IPv4 and IPv6 are configured on the same interface, all IPv4 addresses are over-written in favour of the newer technology.

  2. Incorrect IPv4 addresses are entered on the router interfaces.

  3. RIPng is incompatible with dual-stack technology.

  4. IPv4 is incompatible with RIPng.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

RIPng (RIP next generation) is designed exclusively for IPv6 networks. IPv4 routing uses RIPv1 or RIPv2, which are completely separate protocols. You cannot mix IPv4 routes with RIPng configuration as they operate on different IP stacks.

Multiple choice

Refer to the exhibit. Host1 is in the process of setting up a TCP session with Host2. Host1 has sent a SYN message to begin session establishment. What happens next?

  1. Host1 sends a segment with the ACK flag = 0, SYN flag = 0 to Host2.

  2. Host1 sends a segment with the ACK flag = 1, SYN flag = 0 to Host2.

  3. Host1 sends a segment with the ACK flag = 1, SYN flag = 1 to Host2.

  4. Host2 sends a segment with the ACK flag = 1, SYN flag = 1 to Host1.

  5. Host2 sends a segment with the ACK flag = 0, SYN flag = 1 to Host1.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In TCP's three-way handshake, after the initiator sends a SYN (synchronize) packet, the recipient responds with a SYN-ACK packet - acknowledging the SYN and sending its own synchronize. The final step is the initiator sending an ACK to complete the connection.

Multiple choice

Refer to the exhibit. RIPv1 is configured as the routing protocol for the network that is shown. The following commands are used on each router: router rip network 10.0.0.0
network 172.16.0.0 When this configuration is complete, why users on the LAN of each router are unable to access the remote LANs?

  1. The network statements are configured incorrectly.

  2. A routing loop has been created.

  3. RIPv1 is unable to route to discontiguous subnets of a major network.

  4. RIPv1 is unable to route networks with a /24 subnet mask.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

RIPv1 is a classful routing protocol that does not support subnet masks in its updates. When it encounters discontiguous subnets of the same major network (like 10.0.0.0/8 separated by other networks), it cannot properly route between them because it summarizes all subnets of a major network at network boundaries.

Multiple choice

Refer to the exhibit. What can be concluded from the output of the running-configuration of a router?

  1. The passwords are encrypted.

  2. The current configuration was saved to NVRAM.

  3. The configuration that is shown will be the one used on the next reboot.

  4. The commands that are displayed determine the current operation of the router.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The running-configuration (show running-config) displays the commands that are currently active in RAM and determining the router's operation. The startup-config (in NVRAM) is what's used on next reboot, and password encryption requires a separate command (service password-encryption).

Multiple choice

Refer to the exhibit. R1 is performing NAT overload for the 10.1.1.0/24 inside network. Host A has sent a packet to the web server. What is the destination IP address of the return packet from the web server?

  1. 10.1.1.2:1234

  2. 172.30.20.1:1234

  3. 172.30.20.1:3333

  4. 192.168.1.2:80
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

With NAT overload (PAT), the router translates both the source IP and source port of internal traffic. The web server receives the packet with source IP 172.30.20.1 and source port 3333, so it sends the return packet to that same destination IP and port. The NAT table then translates it back to 10.1.1.2:1234.

Multiple choice

Refer to the exhibit. What is another way to represent this IPv6 address?

  1. 2031::130F::9C0::130B

  2. 2031::130F::9C0:0:130B

  3. 2031:0:130F::9C0::130B

  4. 2031:0:130F::9C0:0:130B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

IPv6 address compression rules allow replacing consecutive zeros with double colon (::), but this can only be done ONCE in an address to avoid ambiguity. Options A, B, and C incorrectly use :: twice. Option D correctly compresses the second hextet (0:0000 becomes 0) and the zero block before 9C0, using :: only once.

Multiple choice

Refer to the exhibit. Which set of commands will configure static routes that will allow the WinterPark and the Altamonte routers to deliver packets from each LAN and direct all other traffic to the Internet?

  1. WinterPark(config)# ==>ip route 0.0.0.0 0.0.0.0 192.168.146.1

  2. Altamonte(config)# ==>ip route 10.0.234.0 255.255.255.0 192.168.146.2

  3. Altamonte(config)# ip route 0.0.0.0 0.0.0.0 s0/1

  4. WinterPark(config)# ip route 0.0.0.0 0.0.0.0 192.168.146.1

  5. Altamonte(config)# ip route 10.0.234.0 255.255.255.0 192.168.146.2
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice

Refer to the exhibit. What is the meaning of the term dynamic in the output of the command?

  1. The bandwidth capability of the interface increases and decreases automatically based on BECNs.

  2. The Serial 0/0/1 interface acquired 172.16.3.1 from a DHCP server.

  3. The mapping between DLCI 100 and 172.16.3.1 was learned through Inverse ARP.

  4. DLCI 100 will automatically adapt to changes in the Frame Relay cloud.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In Frame Relay, 'dynamic' refers to DLCI-to-IP address mappings learned via Inverse ARP, not statically configured. This allows routers to automatically discover which remote IP addresses correspond to which DLCIs without manual configuration. DHCP is unrelated to Frame Relay address assignment.

Multiple choice

Which prompt is used to allow a user to change the IP address of an interface on a router?

  1. Router>

  2. Router#

  3. Router(config)#

  4. Router(config-if)#
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Router configuration modes are hierarchical: User mode (>) > Privileged mode (#) > Global config (config)# > Interface config (config-if)#. To change interface parameters like IP address, you must be in interface configuration mode, accessed via 'interface ' from global config mode.

Multiple choice

Refer to the exhibit. What can be determined from this output?

  1. The router will have to perform recursive lookups to forward a packet destined for 192.168.2.213/24.

  2. The parent route for these networks was removed from the routing table.

  3. A route to 192.168.0.0/25 would be classified as a supernet route for the routes listed in the routing table.

  4. All of the routes listed are network routes.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The routing table shows routes with various subnet masks (/24, /25, /30). These are all 'network routes' because they represent specific network prefixes with their associated subnet masks. A supernet would have a shorter mask than the classful boundary (like /16 for a Class C). Parent routes appear when a more specific route exists, not when removed.

Multiple choice

Refer to the exhibit. What information can be determined from the displayed output?

  1. EIGRP packets are waiting to be sent to the neighbours.

  2. The adjacencies between the routers are yet to be established.

  3. The IP address 192.168.10.10 is configured at serial interface S0/0/1 of router R2.

  4. Router R2 is receiving hello packets from a neighbour with the IP address 192.168.10.10 via the R2 S0/0/1 interface.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The output shows EIGRP hello packets received from a neighbor. The key information is that router R2 (the local router) is receiving hello packets from neighbor 192.168.10.10 via interface S0/0/1. This indicates EIGRP neighbor discovery is working. The hello packets are used to form and maintain EIGRP adjacencies between routers.

Multiple choice

Which Frame Relay flow control mechanism is used to signal routers that they should reduce the flow rate of frames?

  1. DE

  2. BE

  3. CIR

  4. FECN

  5. CBIR
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

FECN (Forward Explicit Congestion Notification) is the Frame Relay mechanism used to signal congestion in the forward direction. When switches detect congestion, they set the FECN bit in frames heading toward the destination to inform routers to slow down their transmission rate. BECN (Backward Explicit Congestion Notification) would signal in the reverse direction, while CIR is the committed information rate, not a signaling mechanism.

Multiple choice

How can a network administrator influence which STP switch becomes the root bridge?

  1. Configure all the interfaces on the switch as the static root ports.

  2. Change the BPDU to a lower value than that of the other switches in the network.

  3. Assign a lower IP address to the switch than that of the other switches in the network.

  4. Set the switch priority to a smaller value than that of the other switches in the network.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In STP, the root bridge is selected based on the lowest bridge ID, which combines priority (default 32768) and MAC address. Setting a lower priority value ensures that switch becomes root. Configuring static root ports is not possible - root ports are determined by the root bridge. IP addresses have no role in STP operation, and BPDU values are not configurable.