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 DoD layer defines protocols such as BGP, IP and ICMP?

  1. Host-to-Host

  2. Internet

  3. Process/Application

  4. Network Access
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The DoD model's Internet layer (equivalent to OSI's Network layer) contains IP, ICMP, and routing protocols like BGP. This layer is responsible for logical addressing, routing, and path determination across networks.

Multiple choice

Refer to the exhibit. You are a network administrator who has been tasked with completing the Frame Relay topology that interconnects two remote sites. Router HQ belongs to both the 172.16.1.0/24 and 172.16.2.0/24 subnets with IP addresses of 172.16.1.3 and 172.16.2.3 respectively. Traffic between R1 and R2 must travel through HQ first. How should the serial interface on HQ be configured to complete the topology?

  1. One multipoint subinterface

  2. Two point-to-point subinterfaces

  3. With the physical interface configured with two ip addresses

  4. One IP address on a point-to-point subinterface and one IP address on the physical interface
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice

Refer to the exhibit. All routers are configured with valid interface addresses in the indicated networks and are running RIPv1. The network is converged. Which routes are present in the routing tables?

  1. All routers have all routes in their routing table.

  2. All routers have all /30 routes, but do not have /24 routes in their routing table.

  3. All routers have all /30 routes. Routers A and E also have some of the /24 routes in their routing table.

  4. All routers have all /30 routes. Routers B and D also have some of the /24 routes in their routing table.

  5. Routers A and E have all routes. Routers B and D have only /30 routes in their routing table.
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice

What is a possible impact of setting too short aging time in the MAC address table of a switch?

  1. Overly large address table

  2. Unnecessary flooding of packets

  3. Excessive timeouts of static addresses

  4. Impaired ability to dynamically learn new addresses
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

MAC address table entries expire after the aging time. If set too short, legitimate entries expire before devices finish communicating, causing the switch to flood frames to all ports because it no longer knows which port leads to the destination MAC address.

Multiple choice

Information about which OSI layers of connected Cisco devices can be verified with the show cdp neighbours command?

  1. All layers

  2. Layer 1, Layer 2, and Layer 3

  3. Layer 1, Layer 2, Layer 3, and Layer 4

  4. Layer 6 and Layer 7
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cisco Discovery Protocol (CDP) operates at Layer 2 but provides information about multiple OSI layers. The 'show cdp neighbours' command displays Layer 1 information (physical connectivity), Layer 2 information (device IDs, port IDs, capabilities), Layer 3 information (IP addresses), and Layer 4 information (OSI version info). It does not provide Layer 5-7 details.

Multiple choice

What does the destination MAC address FF-FF-FF-FF-FF-FF represent?

  1. A multicast destined for a select group of computers on an ethernet network

  2. A broadcast to all hosts in a broadcast domain

  3. The MAC address of a particular host

  4. A frame destined for a single collision domain

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The MAC address FF-FF-FF-FF-FF-FF represents a broadcast to all hosts in a broadcast domain.

Multiple choice

On a router running EIGRP, what database would maintain a list of feasible successors?

  1. Routing table

  2. Neighbour table

  3. Topology table

  4. Adjacency table
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

EIGRP maintains multiple databases: the routing table (best paths), neighbor table (adjacent routers), and topology table (all learned routes). Feasible successors - backup paths with loop-free guarantee - are stored specifically in the topology table. The routing table only contains the successor (best) routes, while feasible successors remain in the topology table as backup options that can be immediately promoted if the successor fails.

Multiple choice

What is a routing loop?

  1. A packet bouncing back and forth between two loopback interfaces on a route.

  2. A condition where a return path from a destination is different from the outbound path forming a loop.

  3. A condition where a packet is constantly transmitted within a series of routers without ever reaching its intended destination.

  4. The distribution of routes from one routing protocol into another.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A routing loop occurs when packets continuously circulate between routers without reaching their destination. This typically happens due to inconsistent routing tables, slow convergence, or incorrect route redistribution. Unlike load balancing where different paths are used, a routing loop is a pathological condition that wastes bandwidth and prevents packet delivery. Option C accurately describes this condition.

Multiple choice

Interface s0/0/0 already has an IP ACL applied inbound. What happens when the network administrator attempts to apply a second inbound IP ACL?

  1. Both ACLs are applied to the interface.

  2. The second ACL is applied to the interface, replacing the first.

  3. The network administrator receives an error.

  4. Only the first ACL remains applied to the interface.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When applying an ACL to an interface, Cisco IOS allows only one ACL per direction per protocol. If an inbound IP ACL is already applied and you attempt to apply another inbound IP ACL, the second ACL replaces the first - you cannot have multiple inbound ACLs on the same interface for the same protocol. This is by design to avoid conflicts and maintain predictable security policies.

Multiple choice

Refer to the exhibit. The exhibited network contains a mixture of Cisco and non-Cisco routers. The command debug ip rip was entered on the JAX router. All routers are running the same version of RIP. Router CHI and Router ORL are not able to reach the 192.168.1.16/28 network. What is a possible solution to this problem?

  1. Enable split horizon in the network.

  2. Configure RIPv2 on routers.

  3. Add network 192.168.1.0 to the RIP configuration on the JAX router.

  4. Configure JAX Fa0/0 as a passive interface.

  5. Enable the Serial0/0/0 interface on the JAX router.
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice

Refer to the exhibit. Security Device Manager (SDM) is installed on router R1. What is the result of opening a web browser on PC1 and entering the URL https://192.168.10.1?

  1. The password is sent in plain text.

  2. A Telnet session is established with R1.

  3. The SDM page of R1 appears with a dialog box that requests a username and password.

  4. The R1 home page is displayed and allows the user to download Cisco IOS images and configuration files.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When accessing a router running SDM via HTTPS, the browser presents the SDM web interface with a login dialog requesting username and password credentials. The HTTPS protocol ensures the password is encrypted during transmission (not plain text). This is not a Telnet session (which uses port 23, not 443), nor does it display a generic home page for downloading IOS files. SDM is a web-based device management tool that requires authentication.