Networks (D325)

Correct Answer

A. Active network connections and listening ports with addresses and port numbers

Explanation

The netstat -an command shows active network connections, listening ports, and their associated IP addresses and port numbers in numerical format. This helps in identifying open ports and active connections, providing a detailed view of the system's network status.

Why other options are wrong

B. Active network connections and listening ports with host names and service names

The -an flag shows numerical addresses and port numbers, not host names or service names. The -a flag shows all connections and listening ports, and -n shows numerical addresses. Host names and service names would require resolving, which is not done with netstat -an.

C. User accounts

The netstat -an command does not provide information about user accounts. To view user accounts, commands like net user or accessing the "Local Users and Groups" interface would be needed.

D. Network shares

The netstat -an command does not display network shares. Network shares are managed and displayed using commands like net share.

Correct Answer

B. Home network

Explanation

A home network is the common setup used by home users to connect multiple devices such as computers, smartphones, tablets, and smart devices. This network allows for sharing of resources, such as files, printers, and internet connectivity, within the home. It can include wired connections (Ethernet) or wireless connections (Wi-Fi), often facilitated by a router.

Why other options are wrong

A. hub/switch

A hub or switch is a networking device that connects multiple devices within a network, but it is not the network itself. These devices can be components of a home network, but they do not describe the network itself.

C. Digital Communication system

A digital communication system refers to a broader concept that includes systems for transmitting digital data, often over larger or more complex networks (such as telecom networks). It is not specifically related to home users connecting multiple computers or devices.

D. Router

A router is a device that routes data between different networks (such as the internet and a local home network). While a router is a key component of a home network, it is not the term that describes the entire network setup. The correct term for connecting multiple devices in a home is "home network."

Correct Answer

A. Web-based application

Explanation

SaaS (Software as a Service) refers to software applications that are hosted on the cloud and delivered over the internet. These applications are typically web-based, meaning they can be accessed via a browser without the need for local installation or infrastructure. SaaS allows users to access software from anywhere with an internet connection, making it convenient and scalable for a wide range of users.

Why other options are wrong

B. Internet infrastructure

SaaS is not an internet infrastructure. It is a software delivery model that relies on infrastructure but is focused on providing applications, not the infrastructure itself.

C. Software that provides good service to general users

While SaaS applications are widely used, it is not limited to "general users." SaaS can cater to both general users and business professionals, offering a wide variety of specialized software solutions.

D. Software that provides good service to expert users

SaaS is not specifically tailored for expert users; it is designed for a wide range of users, including both general and expert users, depending on the application.

Correct Answer

B. Rootkits continue to be used extensively and their usage has not diminished.

Explanation

While rootkits were once widely used by attackers, their usage has diminished in favor of other more sophisticated attack methods, such as malware-as-a-service or more subtle exploits. Rootkits are still in use but are not as commonly encountered as other types of malware due to advances in detection technologies and countermeasures.

Why other options are wrong

A. A rootkit is malware that can hide the presence of other malware.

This is true. Rootkits are specifically designed to conceal the presence of other types of malware by altering system behavior, preventing detection by users or antivirus programs.

C. Rootkits can be used to hide its own presence.

This is true. Rootkits are designed to remain hidden on the infected system and can alter or hide system files and processes, making it difficult to detect their presence.

D. Rootkits cannot be detected by either an OS or common anti malware scanning software.

This is mostly true in the past. Rootkits are difficult to detect using conventional methods because they are designed to evade detection by manipulating the operating system itself and subverting security tools, though advancements in detection have improved the ability to spot them.

Correct Answer

C. Forwards data packets to their network destination.

Explanation

A router is responsible for forwarding data packets between networks. It examines the destination IP address of each packet and determines the best path for forwarding the packet to its destination. Routers connect different networks and ensure data is properly directed through these networks, often using routing tables and protocols.

Why other options are wrong

A. Selects network pathways/links within a network for the flow of data/information.

This describes the function of a router but does not fully capture its role in forwarding data packets across different networks. Routers primarily focus on directing traffic to other networks rather than managing internal network pathways.

B. Provides for communication within the network.

This is more accurately the role of switches and hubs. Routers are used to route traffic between different networks, not just within one network.

D. Amplifies and rebroadcasts signals in a network.

This describes the role of a repeater or hub, which regenerates and amplifies signals to extend their reach across the network. Routers, on the other hand, manage traffic between different networks and do not function as signal amplifiers.

Correct Answer

B. It provides error detection and correction for data frames.

Explanation

The Data Link layer in the TCP/IP model is responsible for ensuring reliable data transfer between devices on the same network. It performs error detection and correction by checking the integrity of data frames as they are transmitted. The layer is also responsible for framing data for transmission, managing access to the physical medium, and detecting physical layer issues.

Why other options are wrong

A. It is responsible for routing packets across multiple networks.

Routing packets across multiple networks is a function of the Network layer, not the Data Link layer. The Network layer is responsible for packet forwarding and routing between devices on different networks.

C. It establishes, manages, and terminates sessions between applications.

Session management is the responsibility of the Session layer in the OSI model, not the Data Link layer. The Session layer manages communication sessions between applications.

D. It encrypts data to ensure secure transmission over the network.

Encryption is typically handled by the Transport or Application layers, depending on the context. The Data Link layer is not responsible for encryption, as its primary role is to ensure data integrity and proper transmission on the same network segment.

Correct Answer

C. Screened subnet

Explanation

A screened subnet, also known as a demilitarized zone (DMZ), is a network architecture that places a device, like a firewall or proxy server, between an external, untrusted network (e.g., the internet) and an internal, trusted network (e.g., a private corporate network). This arrangement helps protect the internal network from external threats while providing controlled access to certain services.

Why other options are wrong

A. Bastion host

A bastion host is a highly secured server that is typically placed in a DMZ. It is a single point of entry into a network, not a network architecture that separates internal and external networks.

B. Screened host

A screened host refers to a host that is protected by a firewall or other security device. It is not a network configuration or architecture, but a part of a security strategy.

D. Extranet

An extranet is a private network that allows controlled access to outsiders, such as business partners. It is not the device or network architecture used to place a firewall between an internal and external network.

Correct Answer

A. A symmetric key block cipher that applies the DES algorithm three times to enhance security.

Explanation

The Triple Data Encryption Standard (3DES) is a symmetric-key block cipher that applies the DES algorithm three times to each data block, effectively enhancing its security compared to standard DES. While DES itself became vulnerable to attacks due to its short key length, 3DES increases the key size and encryption complexity by repeating the encryption process three times, thus providing a higher level of security. This method is widely used in legacy systems but has been mostly replaced by more modern algorithms such as AES.

Why other options are wrong

B. An asymmetric encryption method that uses a pair of keys for secure communication.

3DES is a symmetric encryption algorithm, meaning it uses the same key for both encryption and decryption. Asymmetric encryption, on the other hand, uses a pair of public and private keys, which is not the case for 3DES.

C. A hashing algorithm that converts data into a fixed-size string of characters.

3DES is an encryption algorithm, not a hashing algorithm. Hashing algorithms, such as SHA, generate a fixed-size output from input data, but they are not used for reversible encryption like 3DES.

D. A lightweight encryption technique suitable for mobile devices.

While 3DES offers enhanced security compared to DES, it is not particularly lightweight. In fact, it is considered computationally expensive and has been superseded by more efficient algorithms like AES, which is more suitable for mobile and resource-constrained environments.

Correct Answer

B. They are self-replicating programs that do not need a host file.

Explanation

Computer worms are a type of self-replicating malware that can spread independently across networks without needing a host file. Unlike viruses, which require a host file to execute and spread, worms exploit vulnerabilities in systems and network protocols to propagate themselves. This makes them particularly dangerous as they can spread quickly and without any direct interaction from users.

Why other options are wrong

A. They require a host file to execute and spread

This describes a virus, not a worm. Worms are capable of spreading on their own without needing to attach to a host file.

C. They can only spread through email attachments

While worms can spread through email attachments, they are not limited to this method. Worms can also spread through network vulnerabilities, instant messaging, or malicious websites.

D. They are a type of malware that can only infect mobile devices

Worms can infect various types of devices, not just mobile devices. They primarily target computers and networked systems, exploiting vulnerabilities regardless of the device type.