CompTIA N10-009 Network+ Exam Dumps and Practice Test Questions Set 10 Q136-150
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Question 136
Which type of wireless attack involves intercepting and replaying legitimate authentication messages to gain unauthorized access?
A) Rogue AP
B) Evil Twin
C) Replay Attack
D) Jamming
Answer: C) Replay Attack
Explanation:
A replay attack is a type of wireless network attack in which an attacker intercepts legitimate authentication messages, captures them, and retransmits the same data to gain unauthorized access to a network or system. In wireless networks, this often involves capturing packets during the authentication process, such as the handshake between a client device and an access point, and replaying them later to impersonate a legitimate device. This type of attack exploits the fact that some authentication protocols do not use sufficient randomness or do not enforce unique session identifiers for each handshake, allowing previously captured messages to be reused successfully.
Rogue AP attacks involve setting up unauthorized access points that mimic legitimate network SSIDs to trick users into connecting, but they do not specifically rely on replaying captured authentication messages. Evil Twin attacks are similar to rogue APs, where an attacker configures a malicious access point with the same SSID and security settings as a legitimate network to intercept traffic, but the attack does not necessarily replay authentication messages. Jamming attacks disrupt wireless communication by overwhelming the frequency channel with interference, preventing devices from establishing or maintaining connections, and do not capture or replay authentication packets.
Replay attacks are particularly dangerous because they can bypass standard authentication mechanisms if the protocol does not implement protections such as nonces, timestamps, or session tokens. For example, in WEP-protected networks, the reuse of initialization vectors allows attackers to capture encrypted frames and replay them to gain access or decrypt sensitive data. Modern protocols like WPA2 and WPA3 mitigate replay attacks by incorporating robust encryption, unique session keys, and mechanisms such as the 4-way handshake in WPA2 or Simultaneous Authentication of Equals (SAE) in WPA3 to prevent captured authentication data from being reused.
The correct answer is a replay attack because it specifically refers to intercepting and retransmitting legitimate authentication data to gain unauthorized access. Mitigation strategies involve using protocols that employ unique session identifiers, random nonces, and cryptographic protections to ensure each authentication attempt is distinct. Administrators must configure wireless networks to use WPA2 or WPA3 with strong passwords and avoid outdated protocols like WEP, which are vulnerable to replay attacks. Monitoring network traffic for duplicate or suspicious authentication attempts also helps in detecting replay attempts before unauthorized access is granted.
Replay attacks highlight the importance of secure encryption, robust authentication protocols, and careful network monitoring. By implementing mechanisms that prevent authentication messages from being valid when reused, organizations reduce the risk of unauthorized access to sensitive systems. Security best practices include regular updates to access points, strong encryption standards, network segmentation, and monitoring for unusual connection patterns. Understanding the mechanisms of replay attacks, their impact, and effective defenses is essential for maintaining secure wireless environments, ensuring network integrity, and protecting data confidentiality.
Replay attacks can be combined with other attack types, such as man-in-the-middle attacks, to further exploit captured traffic or credentials. Security professionals must evaluate wireless network protocols, authentication mechanisms, and encryption standards to ensure they provide adequate protection against this type of threat. Effective mitigation requires both technical controls, such as protocol configuration, and administrative measures, such as employee awareness and security policy enforcement. Replay attacks remain a significant threat in environments where legacy or misconfigured wireless security protocols are in use, emphasizing the need for ongoing vigilance and modern security practices.
Question 137
Which network topology connects all devices in a closed loop, allowing data to travel in one or both directions?
A) Star
B) Ring
C) Mesh
D) Bus
Answer: B) Ring
Explanation:
A ring topology is a network configuration in which all devices are connected in a closed loop, forming a continuous pathway for data to travel. In a ring, each device is connected to exactly two other devices, and data travels from one device to the next until it reaches its destination. Ring topologies can operate in unidirectional or bidirectional mode. In unidirectional rings, data flows in a single direction around the loop, while in bidirectional rings, data can flow in both directions, providing redundancy and increasing fault tolerance. Ring topologies can use token-passing mechanisms, where a special data frame called a token circulates, granting permission to transmit and preventing collisions on the network.
Star topology connects all devices to a central switch or hub, providing simplicity and centralized management, but it does not create a closed loop for data travel. Mesh topology involves devices being interconnected with multiple paths, offering redundancy and fault tolerance, but it does not form a single closed loop. Bus topology connects devices along a single backbone, where signals propagate in both directions, but it lacks the looping structure of a ring.
Ring networks were commonly used in older technologies such as Token Ring and FDDI (Fiber Distributed Data Interface), providing predictable network access and collision-free operation through token-passing. The primary advantage of ring topology is its ability to regulate access, avoid collisions, and efficiently utilize bandwidth when properly implemented. Fault tolerance can be enhanced in modern implementations by adding dual rings or using self-healing mechanisms that reroute traffic if a link or device fails.
The correct answer is ring because it specifically describes a network configuration where all devices are connected in a closed loop, enabling data to travel sequentially from one device to another. Administrators must understand ring operation, token-passing protocols, and potential failure points to maintain network reliability. Monitoring devices and implementing redundancy help prevent downtime, especially in enterprise environments or metropolitan area networks where ring topologies are still relevant.
Ring topology emphasizes predictable traffic flow, reduced collision risk, and structured access control. While less common in modern LAN deployments, it remains significant in specific scenarios requiring deterministic network behavior. Understanding the advantages and limitations of ring topology, including fault management, scalability, and latency considerations, allows network engineers to design efficient and reliable networks. Proper configuration and maintenance ensure that data circulates without interruption, preserving the integrity and performance of communication systems within the ring structure.
Ring networks are resilient when designed with dual rings or bypass mechanisms, providing continuity in case of individual link or device failure. While modern Ethernet star topologies have largely replaced physical rings, logical ring implementations still exist in technologies like SONET/SDH networks or certain industrial and campus networks. Knowledge of ring topology principles, token-passing protocols, and fault recovery methods is essential for network professionals managing legacy networks or designing specialized high-reliability systems.
Question 138
Which protocol is used to resolve human-readable domain names into IP addresses for network communication?
A) DHCP
B) DNS
C) ARP
D) NTP
Answer: B) DNS
Explanation:
DNS, or Domain Name System, is a critical network protocol that translates human-readable domain names, such as www.example.com, into IP addresses, which devices use to route data across networks. The hierarchical structure of DNS ensures scalability, fault tolerance, and distributed management, allowing billions of devices to locate each other on the Internet efficiently. When a client needs to communicate with a server, it queries a DNS resolver, which traverses the DNS hierarchy—including root servers, top-level domain (TLD) servers, and authoritative servers—to obtain the correct IP address. This resolution process enables users to interact with websites, email servers, or other network services without needing to memorize numerical IP addresses.
DHCP dynamically assigns IP addresses and other configuration information to devices on a network, but does not translate hostnames to IP addresses. ARP resolves IP addresses to MAC addresses within a local network, enabling Layer 2 communication, but it does not handle human-readable names or global resolution. NTP synchronizes clocks across devices and has no role in translating names to IP addresses.
DNS supports various record types, including A records for IPv4 addresses, AAAA records for IPv6 addresses, MX records for mail servers, and CNAME records for aliases, providing comprehensive resolution capabilities. Security mechanisms such as DNSSEC ensure the authenticity and integrity of DNS responses, preventing attacks like cache poisoning or spoofing, where attackers provide false address mappings to redirect traffic or capture sensitive information. Administrators can also configure internal DNS servers for private networks, enabling fast resolution of internal resources while maintaining separation from public domains.
The correct answer is DNS because it specifically provides hostname-to-IP address resolution, a foundational service for Internet and network communications. Understanding DNS operation, caching behavior, and the hierarchical query process is essential for troubleshooting connectivity issues, optimizing network performance, and ensuring reliable access to resources. Proper configuration and monitoring of DNS servers, including redundancy, zone transfers, and security policies, are vital to maintaining high availability and preventing disruptions in service.
DNS can be exploited in attacks such as DNS tunneling, amplification, and cache poisoning, emphasizing the need for secure configurations and monitoring. Administrators should employ split-horizon DNS for internal/external resolution separation, configure firewalls to restrict DNS queries, and deploy intrusion detection systems to monitor anomalous traffic. With the growth of cloud services, mobile devices, and IoT, DNS remains central to efficient network communication, enabling seamless device connectivity across diverse platforms and environments.
DNS is a cornerstone of modern networking, providing the essential function of translating human-readable domain names into machine-readable IP addresses. Secure, well-configured DNS infrastructure ensures accessibility, reliability, and integrity for global communication. By understanding the hierarchical nature of DNS, its record types, caching mechanisms, and security considerations, network professionals can optimize connectivity, prevent downtime, and protect against common DNS-based attacks, maintaining robust and scalable network operations.
Question 139
Which protocol is used to remotely monitor and manage network devices, providing metrics such as traffic, errors, and configuration details?
A) SNMP
B) ICMP
C) SMTP
D) FTP
Answer: A) SNMP
Explanation:
SNMP, or Simple Network Management Protocol, is a widely used protocol for remotely monitoring and managing network devices, including routers, switches, firewalls, servers, and printers. SNMP enables administrators to collect real-time metrics such as network traffic, error rates, CPU utilization, memory usage, and configuration settings. By using a combination of management stations, agents, and Management Information Bases (MIBs), SNMP facilitates centralized monitoring and control of network performance, health, and configuration. SNMP operates over UDP, primarily using ports 161 for queries and 162 for traps, allowing devices to send asynchronous alerts to management systems when predefined conditions occur.
ICMP is used for diagnostics and error reporting, such as ping or traceroute, but does not provide detailed device management or configuration capabilities. SMTP is used for sending email messages, not network monitoring or device management. FTP transfers files and does not provide insights into device metrics or network performance.
SNMP consists of three components: the managed device with an SNMP agent, a management station that queries or receives traps, and a MIB that defines the structure of the monitored data. Versions of SNMP, including SNMPv1, v2c, and v3, provide varying levels of security, authentication, and encryption. SNMPv3 is recommended because it includes secure authentication and data encryption, mitigating vulnerabilities present in earlier versions that transmitted sensitive data in plaintext.
The correct answer is SNMP because it provides comprehensive monitoring and management capabilities, enabling administrators to maintain network health and optimize performance. SNMP allows proactive detection of faults, resource bottlenecks, and misconfigurations, improving overall network reliability. Administrators can configure alerts, automate responses to critical events, and generate reports for capacity planning and compliance purposes. Proper configuration, including secure credentials, access control, and monitoring of SNMP traffic, is essential to prevent unauthorized access and misuse, as SNMP can be exploited if left unsecured.
SNMP is integral to modern network management systems, supporting fault management, performance analysis, and configuration monitoring. It is particularly important in large-scale environments where manual monitoring is impractical. By deploying SNMP effectively, organizations gain visibility into network behavior, identify trends, and implement corrective actions before performance degradation or outages occur. SNMP complements other network monitoring tools and protocols, forming a critical component of a proactive network management strategy.
SNMP provides a structured, standardized approach to network monitoring and management. By collecting metrics, detecting anomalies, and enabling centralized control, SNMP ensures network reliability, operational efficiency, and security. Administrators must understand SNMP components, security features, and best practices to deploy it effectively and maintain robust network operations across diverse environments.
Question 140
Which type of network address is used to uniquely identify a device at Layer 2 of the OSI model?
A) IP Address
B) MAC Address
C) Port Number
D) Hostname
Answer: B) MAC Address
Explanation:
A MAC address, or Media Access Control address, is a unique hardware identifier assigned to a network interface card (NIC) and is used to identify a device at Layer 2 of the OSI model. MAC addresses are globally unique, typically 48 bits in length, and are expressed in hexadecimal format. They enable devices to communicate within a local area network by providing a distinct identifier that switches use to forward frames to the correct destination. MAC addresses are essential for Ethernet, Wi-Fi, and other data link layer technologies to operate correctly, ensuring that frames are delivered to the intended device without relying on IP addresses, which operate at Layer 3.
IP addresses are Layer 3 identifiers used to route packets across networks, not for identifying devices at the data link layer. Port numbers identify specific processes or services on a host, allowing applications to receive the correct data, but they do not uniquely identify devices on a network. Hostnames are human-readable names mapped to IP addresses via DNS, facilitating ease of use but lacking a unique physical identifier at Layer 2.
MAC addresses are hardcoded into NICs by manufacturers, although some devices allow software-based modification, known as MAC spoofing. Switches use MAC addresses to build forwarding tables and efficiently deliver frames within a LAN. Address resolution protocols, such as ARP, map IP addresses to MAC addresses to facilitate communication between Layer 3 and Layer 2. MAC addresses also play a role in security, allowing administrators to implement MAC-based filtering, access control lists, and network monitoring.
The correct answer is MAC address because it provides a unique, hardware-based identifier at the data link layer. Understanding MAC addresses is fundamental for troubleshooting network connectivity, configuring VLANs, segmenting traffic, and securing networks against unauthorized devices. MAC addresses ensure accurate frame delivery, enable efficient switching, and form the foundation for many Layer 2 networking features. Network administrators must maintain awareness of MAC address structures, formatting conventions, and potential security implications, including MAC address spoofing and unauthorized access.
MAC addresses support efficient, collision-free communication within LANs and enable devices to participate in Ethernet, Wi-Fi, and other Layer 2 protocols. By managing and monitoring MAC addresses, administrators can ensure proper device identification, enforce network policies, and maintain network performance and security. The role of MAC addresses in bridging Layer 2 and Layer 3 communication is critical for the proper operation of modern networks, including VLAN segmentation, ARP resolution, and secure network access.
Question 141
Which wireless standard operates in the 5 GHz band and supports higher throughput compared to older standards?
A) 802.11b
B) 802.11g
C) 802.11n
D) 802.11ac
Answer: D) 802.11ac
Explanation:
802.11ac, also known as Wi-Fi 5, is a wireless networking standard that operates primarily in the 5 GHz frequency band and provides higher throughput compared to older standards such as 802.11b, g, and n. It achieves increased speeds through the use of wider channel bandwidths (up to 160 MHz), higher-order modulation schemes like 256-QAM, and multiple-input multiple-output (MIMO) technology, which allows multiple data streams to be transmitted and received simultaneously. By leveraging these features, 802.11ac can deliver gigabit-class speeds, making it suitable for bandwidth-intensive applications like HD video streaming, online gaming, and enterprise wireless networks.
802.11b operates in the 2.4 GHz band and provides a maximum theoretical throughput of 11 Mbps, making it one of the earliest Wi-Fi standards and inadequate for modern high-speed requirements. 802.11g also operates in the 2.4 GHz band and increases throughput to 54 Mbps, but it is still limited compared to 802.11ac and is susceptible to interference from common devices like microwaves and Bluetooth peripherals. 802.11n operates in both 2.4 GHz and 5 GHz bands, offering improved throughput through MIMO and channel bonding, but it generally supports lower maximum speeds than 802.11ac and may face congestion on the 2.4 GHz spectrum.
802.11ac’s exclusive focus on the 5 GHz band reduces interference from legacy devices and crowded networks, improving performance in dense environments. Its use of beamforming technology further enhances signal strength and reliability by directing Wi-Fi signals toward connected devices rather than broadcasting uniformly in all directions. The correct answer is 802.11ac because it is designed for high throughput, reduced interference, and efficient use of the 5 GHz band. Proper deployment of 802.11ac requires compatible client devices, careful channel planning, and consideration of coverage areas, as higher frequencies have shorter range and reduced ability to penetrate walls compared to 2.4 GHz.
Understanding 802.11ac is essential for network engineers and administrators tasked with designing and maintaining high-performance wireless networks. It allows organizations to support more users simultaneously, reduce latency, and provide reliable connectivity for modern applications. Network professionals must also consider backward compatibility, as 802.11ac devices often coexist with older Wi-Fi standards, which may influence overall network performance. Security implementation using WPA2 or WPA3 remains critical to protect the wireless infrastructure from unauthorized access.
802.11ac represents a significant advancement over earlier Wi-Fi standards, delivering higher throughput, better reliability, and improved performance in the 5 GHz band. By leveraging MIMO, wider channel bandwidths, beamforming, and higher-order modulation, it provides robust wireless connectivity capable of supporting demanding applications and high-density environments. Understanding its capabilities, deployment considerations, and integration with modern wireless security protocols is essential for optimizing network performance, ensuring user satisfaction, and maintaining a secure, high-speed Wi-Fi infrastructure.
Question 142
Which layer of the OSI model is responsible for establishing, managing, and terminating sessions between applications?
A) Transport
B) Session
C) Presentation
D) Application
Answer: B) Session
Explanation:
The Session layer, Layer 5 of the OSI model, is responsible for establishing, managing, and terminating sessions between applications on different devices in a network. A session represents a continuous exchange of information, often involving authentication, synchronization, and state management to maintain communication integrity. The Session layer ensures that data streams are properly synchronized and organized, allowing applications to resume communication after interruptions, manage dialog control, and maintain logical connections between communicating entities.
The Transport layer (Layer 4) provides end-to-end communication, error detection, and flow control, using protocols like TCP or UDP, but it does not manage application-specific sessions or dialog control. The Presentation layer (Layer 6) is responsible for data formatting, translation, encryption, and compression to ensure interoperability between systems, but it does not manage session states. The Application layer (Layer 7) provides services directly to applications, including email, file transfer, and web browsing, but relies on the Session layer to establish and maintain communication sessions.
Session layer functionality includes establishing connections, managing data exchange, synchronizing communication points, and terminating sessions when communication ends. Examples of protocols and services utilizing the Session layer include RPC (Remote Procedure Call), NetBIOS, PPTP, and session management mechanisms in modern web applications and APIs. The correct answer is Session because it explicitly handles the lifecycle and management of communication sessions between applications. Proper session management is crucial for maintaining the reliability, integrity, and order of data exchanges, especially in environments where multiple sessions occur concurrently or where interruptions may occur due to network conditions.
Understanding the Session layer is critical for network administrators, application developers, and security professionals. Session management ensures that communication between devices is properly maintained, reduces the risk of data loss, and enables applications to recover from network disruptions. Security considerations, such as session authentication, session tokens, and encryption, are often implemented at this layer or in collaboration with the Presentation and Application layers to prevent unauthorized access and session hijacking.
The Session layer plays a vital role in the OSI model by providing structured control over application interactions. It establishes, manages, and terminates sessions, ensures synchronization and recovery, and enables reliable communication between applications across diverse networks. By understanding the responsibilities and mechanisms of the Session layer, professionals can optimize application performance, maintain session integrity, and implement robust security practices, supporting reliable, organized, and efficient network communications for complex applications and services.
Question 143
Which technology allows multiple virtual networks to coexist on a single physical network infrastructure while keeping traffic isolated?
A) VLAN
B) VPN
C) NAT
D) Subnetting
Answer: A) VLAN
Explanation:
A VLAN, or Virtual Local Area Network, is a technology that allows multiple virtual networks to coexist on a single physical network infrastructure while keeping traffic logically isolated. VLANs operate at Layer 2 of the OSI model and enable network administrators to group devices based on factors such as function, department, or project, regardless of their physical location. Each VLAN has a unique identifier, known as a VLAN ID, and traffic within one VLAN is segregated from traffic in other VLANs, providing security, reduced broadcast domains, and improved network efficiency.
VPNs create secure, encrypted tunnels over public or untrusted networks, allowing remote devices to connect to private networks, but they do not provide multiple virtual networks on a single physical LAN. NAT allows multiple devices to share a single public IP address, but does not isolate traffic within a network. Subnetting divides an IP address range into smaller logical segments for routing efficiency, but it does not inherently segregate Layer 2 traffic on the same physical infrastructure.
VLANs are implemented using managed switches that tag frames with VLAN identifiers according to IEEE 802.1Q standards. VLAN tagging enables switches to forward frames to the appropriate VLAN ports and maintain isolation even when multiple VLANs share the same trunk links. By isolating broadcast traffic, VLANs reduce congestion and enhance security, as devices in one VLAN cannot directly communicate with devices in another VLAN without routing or firewall rules. This segmentation is particularly useful in large organizations, data centers, or environments with diverse departments or functional areas.
The correct answer is VLAN because it provides logical segmentation of a physical network, maintaining isolated traffic flows and allowing multiple virtual networks to operate independently. Proper VLAN configuration involves assigning appropriate ports, defining trunk links, and ensuring that inter-VLAN routing is controlled and secure. Network administrators must also consider security policies, including VLAN hopping prevention, access controls, and monitoring, to prevent unauthorized access and potential attacks across VLAN boundaries.
VLANs offer flexibility in network design, enabling administrators to move devices between logical networks without changing physical cabling. They also simplify network management, improve performance by limiting broadcast domains, and support quality of service (QoS) policies for critical applications. Understanding VLAN implementation, tagging, and management is essential for network engineers to optimize performance, ensure security, and maintain scalable, efficient network operations.
VLANs are a fundamental technology for modern network design, providing logical segmentation, security, and efficient traffic management on a single physical infrastructure. By properly configuring VLANs, network professionals can ensure that multiple departments or user groups can operate securely and independently while sharing the same physical network resources, maintaining high performance, and enabling flexible network management.
Question 144
Which type of attack involves sending unsolicited messages to multiple users to obtain sensitive information or install malware?
A) Phishing
B) Spoofing
C) Sniffing
D) DDoS
Answer: A) Phishing
Explanation:
Phishing is a social engineering attack in which an attacker sends unsolicited messages to multiple users, often via email, instant messaging, or other communication channels, with the goal of obtaining sensitive information such as login credentials, financial details, or personal data, or persuading users to install malware. Phishing attacks typically impersonate legitimate entities such as banks, online services, or colleagues, and use urgent language, spoofed sender addresses, and convincing content to deceive recipients into taking action.
Spoofing involves pretending to be another device or entity to deceive users or systems, such as IP spoofing, email spoofing, or ARP spoofing, but it does not necessarily involve sending bulk messages to extract information. Sniffing captures network traffic to obtain sensitive information but relies on passive or active monitoring rather than deceptive messaging. DDoS attacks aim to overwhelm systems with excessive traffic to cause disruption, rather than collecting sensitive data.
Phishing can take various forms, including email phishing, spear phishing, whaling, smishing (SMS-based), and vishing (voice-based). Spear phishing targets specific individuals or organizations with personalized messages, while whaling targets high-profile executives. Effective phishing campaigns exploit human psychology, urgency, fear, and trust to increase the likelihood of user compliance. Attackers often use malicious links, attachments, or forms to harvest credentials, download malware, or redirect users to fraudulent websites.
The correct answer is phishing because it involves sending unsolicited messages to multiple users to trick them into revealing sensitive information or executing malicious actions. Mitigation strategies include user education, spam filtering, email authentication mechanisms like SPF, DKIM, and DMARC, and multi-factor authentication to reduce the impact of compromised credentials. Organizations must also implement anti-phishing policies, security awareness training, and monitoring for suspicious communication patterns to detect and respond to phishing attempts.
Phishing highlights the importance of a layered security approach combining technical controls and human awareness. Users should verify the legitimacy of messages, avoid clicking unknown links, and report suspicious activity. Security teams should simulate phishing exercises to assess vulnerability and improve employee resilience. Understanding phishing tactics, indicators, and mitigation techniques is critical for maintaining organizational security, protecting sensitive data, and preventing malware infections and credential theft.
Phishing remains one of the most common and effective attack vectors due to its reliance on human behavior rather than purely technical exploitation. By educating users, deploying protective technologies, and monitoring communication channels, organizations can minimize the risk and impact of phishing attacks, safeguarding sensitive information and maintaining trust in digital communications.
Question 145
Which network protocol allows dynamic assignment of IP addresses and other configuration parameters to devices?
A) DNS
B) DHCP
C) ARP
D) ICMP
Answer: B) DHCP
Explanation:
DHCP, or Dynamic Host Configuration Protocol, is a network protocol that allows the automatic assignment of IP addresses, subnet masks, default gateways, and other configuration parameters to devices on a network. DHCP simplifies network management by dynamically allocating IP addresses from a predefined pool, reducing the need for manual configuration, preventing conflicts, and ensuring efficient utilization of available addresses. When a device connects to a network, it sends a DHCP discovery message, receives an offer from a DHCP server, requests a lease, and then obtains configuration parameters, enabling immediate network communication.
DNS resolves domain names to IP addresses but does not assign network configuration information to devices. ARP maps IP addresses to MAC addresses on local networks, allowing communication at the data link layer but does not dynamically assign IP addresses. ICMP is used for diagnostics and error reporting, such as ping or traceroute, and is not involved in address assignment.
DHCP supports features such as lease durations, reservation of specific addresses for devices, and options for providing additional parameters like DNS servers, NTP servers, and network boot information. It reduces administrative overhead and supports mobility in environments with frequent device connections, such as offices, schools, or public networks. DHCP can operate across subnets using relay agents to forward requests to centralized servers, ensuring scalability in large networks.
The correct answer is DHCP because it provides dynamic, automated network configuration, enabling devices to communicate efficiently without manual intervention. Security considerations include preventing rogue DHCP servers, implementing DHCP snooping, and limiting access to trusted devices. Proper DHCP deployment ensures address consistency, network efficiency, and simplified management while supporting network expansion and device mobility. Administrators must monitor lease utilization, manage address pools, and implement redundancy for high availability.
DHCP is a fundamental network protocol that automates IP address and configuration assignment, facilitating efficient network operations, reducing errors, and supporting scalable and dynamic environments. By understanding DHCP operation, configuration options, and security best practices, administrators can maintain reliable, efficient, and secure network connectivity for diverse devices and users.
Question 146
Which type of cable is most commonly used to connect devices over short distances in Ethernet networks while supporting high-speed data transmission?
A) Coaxial
B) Fiber Optic
C) Twisted Pair
D) HDMI
Answer: C) Twisted Pair
Explanation:
Twisted pair cables are the most commonly used medium for connecting devices over short to moderate distances in Ethernet networks while supporting high-speed data transmission. Twisted pair cables consist of pairs of insulated copper wires twisted together to reduce electromagnetic interference (EMI) and crosstalk between adjacent pairs. The twisting helps to cancel out external interference, making twisted pair an effective and economical choice for network connectivity in local area networks (LANs). Twisted pair cables are widely available in several categories, including Cat5e, Cat6, Cat6a, and Cat7, each offering different bandwidth capabilities and maximum data rates.
Coaxial cables, historically used in older Ethernet networks such as 10Base2 and 10Base5, consist of a central conductor, insulating layer, metallic shield, and protective outer layer. While coaxial provides good shielding and can support longer distances than twisted pair in some cases, it has largely been replaced by twisted pair and fiber optic cables in modern LAN deployments due to lower cost, flexibility, and ease of termination. Fiber optic cables transmit data using light pulses through glass or plastic cores and offer extremely high bandwidth and long-distance capabilities without electrical interference. Fiber is preferred for backbone connections, data centers, or environments requiring high-speed long-distance transmission, but it is more expensive and requires specialized equipment and installation expertise. HDMI cables are designed for audio and video transmission and are not used for Ethernet network connectivity.
Twisted pair cables can be unshielded (UTP) or shielded (STP), with unshielded twisted pair being the most commonly used in office and enterprise networks. Category 5e (Cat5e) supports up to 1 Gbps over distances of 100 meters, Cat6 supports up to 10 Gbps for shorter distances, and Cat6a and Cat7 extend high-speed capabilities with improved shielding and crosstalk reduction. Twisted pair cables use RJ45 connectors for termination and are compatible with Ethernet switches, routers, and network interface cards. The physical flexibility, ease of installation, and compatibility with Ethernet standards make twisted pair the preferred medium for most modern LAN installations.
The correct answer is twisted pair because it provides reliable, cost-effective, and high-speed connectivity for Ethernet networks over short to moderate distances. Network professionals must understand the different categories of twisted pair cables, their speed and distance limitations, and installation best practices to ensure optimal performance and minimize errors caused by crosstalk, interference, or poor terminations. Proper cable management, testing, and adherence to standards such as TIA/EIA-568 ensure consistent network performance and support high-speed applications.
Twisted pair cables remain the dominant medium for connecting devices in Ethernet LANs due to their combination of cost-effectiveness, flexibility, and support for modern high-speed standards. By selecting the appropriate category and implementing best practices, administrators can optimize network performance, ensure reliability, and provide a scalable infrastructure capable of supporting evolving bandwidth demands. Understanding twisted pair characteristics, including shielding, category ratings, and connector types, is essential for designing, deploying, and maintaining efficient and robust networks.
Question 147
Which type of firewall examines traffic at the application layer and can enforce rules based on specific applications or services?
A) Packet Filtering Firewall
B) Stateful Firewall
C) Proxy Firewall
D) Next-Generation Firewall
Answer: D) Next-Generation Firewall
Explanation:
A next-generation firewall (NGFW) is a security device that examines traffic at the application layer and can enforce rules based on specific applications, services, or content. Unlike traditional packet-filtering or stateful firewalls, NGFWs integrate deep packet inspection, intrusion prevention, antivirus scanning, application awareness, and user identity tracking to provide comprehensive security. By analyzing the contents of traffic and associating it with particular applications, NGFWs can allow or block traffic based on granular policies rather than simply relying on IP addresses or port numbers. This capability enables organizations to control access to modern applications such as cloud services, social media, streaming platforms, or custom enterprise applications.
Packet filtering firewalls operate at Layer 3 and 4, inspecting headers to allow or block traffic based on source/destination IP addresses, ports, and protocols. While simple and efficient, packet filtering cannot analyze the contents of traffic, making it ineffective against application-specific threats. Stateful firewalls maintain connection state information, providing enhanced security by tracking the state of active sessions and ensuring that only legitimate responses are allowed. However, they also lack the deep inspection and application-level granularity offered by NGFWs. Proxy firewalls, sometimes called application-layer gateways, can inspect application traffic, but they typically focus on specific protocols like HTTP or FTP and may not integrate the extensive security features found in modern NGFWs.
NGFWs combine multiple security functions into a single platform, providing unified threat management, SSL decryption, antivirus scanning, intrusion prevention, URL filtering, and application awareness. Administrators can define policies to control user access, monitor application usage, and detect threats in real time. NGFWs are particularly important in modern enterprise networks, where traditional port-based security rules are insufficient to address complex threats, encrypted traffic, and evolving application behaviors.
The correct answer is next-generation firewall because it operates at the application layer, providing deep inspection and granular control over network traffic based on application type, user identity, or content. Implementing NGFWs enhances network security, reduces exposure to advanced threats, and ensures that policy enforcement is aligned with organizational requirements. Proper configuration involves defining application rules, integrating threat intelligence, managing SSL decryption policies, and monitoring logs to identify suspicious activity. NGFWs also provide visibility into network activity, helping administrators optimize performance, enforce compliance, and detect malicious behavior.
Next-generation firewalls represent the evolution of network security, combining application-layer inspection, intrusion prevention, and identity awareness in a single device. By leveraging NGFWs, organizations can protect against advanced threats, enforce granular policies, and gain insights into application usage. Understanding NGFW capabilities, configuration, and operational considerations is essential for network professionals tasked with maintaining secure, resilient, and compliant network environments.
Question 148
Which protocol is used to provide secure, encrypted web traffic between clients and servers over the Internet?
A) HTTP
B) HTTPS
C) FTP
D) Telnet
Answer: B) HTTPS
Explanation:
HTTPS, or Hypertext Transfer Protocol Secure, is a protocol used to provide secure, encrypted web traffic between clients and servers over the Internet. HTTPS combines standard HTTP communication with Transport Layer Security (TLS) or formerly Secure Sockets Layer (SSL) encryption to ensure data confidentiality, integrity, and authenticity. When a client initiates an HTTPS session, the server presents a digital certificate issued by a trusted certificate authority (C A) to validate its identity. Once the client verifies the certificate, a secure session key is established, enabling encrypted communication. This prevents eavesdropping, tampering, or interception of sensitive data such as passwords, financial information, or personal data during transmission.
HTTP is the standard protocol for web communication but does not provide encryption, leaving data vulnerable to interception. FTP is a file transfer protocol that transmits credentials and data in plaintext unless combined with secure variants like FTPS or SFTP. Telnet provides remote command-line access but transmits information without encryption, making it insecure for modern use.
HTTPS ensures that web applications, e-commerce platforms, online banking services, and other Internet services maintain user trust and security. It also supports modern features such as HTTP/2 and HTTP/3, which improve performance, connection multiplexing, and latency reduction while retaining encryption and authentication. Web browsers display visual indicators like padlock icons to signal that a connection is secure, helping users verify site legitimacy.
The correct answer is HTTPS because it specifically combines HTTP functionality with encryption to secure web traffic. Administrators and developers must implement HTTPS correctly, including obtaining valid certificates, configuring TLS settings, supporting strong cipher suites, and redirecting HTTP requests to HTTPS. This ensures data confidentiality, integrity, and protection against man-in-the-middle attacks. Organizations should monitor certificates for expiration, enforce certificate pinning if necessary, and comply with best practices for secure web deployment.
HTTPS is the standard protocol for securing web communications, providing encrypted, authenticated connections that protect sensitive data from interception or tampering. Understanding HTTPS implementation, TLS encryption, certificate management, and related security considerations is essential for network and web professionals to maintain secure, reliable, and trusted Internet services. Proper deployment ensures compliance, enhances user confidence, and protects critical information in modern online environments.
Question 149
Which protocol is used to securely transfer files over a network using encryption and authentication?
A) FTP
B) SFTP
C) TFTP
D) HTTP
Answer: B) SFTP
Explanation:
SFTP, or Secure File Transfer Protocol, is a protocol used to securely transfer files over a network while providing encryption and authentication. Unlike traditional FTP, which transmits data and credentials in plaintext and is vulnerable to interception, SFTP operates over the SSH protocol, ensuring that both authentication and file data are encrypted during transmission. By using SSH for transport, SFTP provides confidentiality, integrity, and authentication, making it a secure choice for transferring sensitive files across untrusted networks such as the Internet.
FTP, or File Transfer Protocol, allows file transfer between clients and servers but transmits usernames, passwords, and file content in plaintext, exposing sensitive information to potential attackers. TFTP, or Trivial File Transfer Protocol, is a simplified, unsecured file transfer protocol with no authentication or encryption, suitable for small, controlled environments but inappropriate for sensitive data. HTTP is a protocol for web traffic and is not designed for file transfers, nor does it provide encryption unless combined with HTTPS.
SFTP supports several key security features, including public-key or password authentication for users, secure session establishment via SSH, and encrypted data channels that prevent eavesdropping and man-in-the-middle attacks. SFTP also provides integrity checks for transferred files, ensuring that they are not altered during transmission. Additionally, SFTP supports multiple file operations, including uploading, downloading, directory listing, renaming, and deleting files, all while maintaining encryption and security policies.
The correct answer is SFTP because it combines secure authentication and encrypted file transfer, ensuring that sensitive data is protected in transit. Organizations often deploy SFTP for tasks such as secure backups, sharing confidential documents, and transferring data between remote sites or cloud services. Administrators must configure SFTP servers with proper access controls, authentication methods, and logging to monitor activity, detect unauthorized attempts, and maintain compliance with security standards.
SFTP provides an advantage over FTP and TFTP by eliminating the need for separate encryption mechanisms and ensuring that all communication is automatically secured by the underlying SSH protocol. Network professionals must also consider best practices such as disabling password-based authentication in favor of key-based authentication, limiting user permissions, enforcing strong encryption algorithms, and monitoring session activity. These measures protect against unauthorized access, data leakage, and malicious activity.
SFTP is the preferred protocol for secure file transfer due to its integrated encryption, authentication, and file integrity mechanisms. Understanding SFTP operation, SSH integration, authentication options, and security policies is essential for administrators responsible for secure data transfer. Proper implementation ensures confidentiality, prevents unauthorized access, and maintains reliable and secure file exchange across networks. Organizations relying on secure data movement must deploy SFTP with robust configuration, user management, and monitoring to achieve the highest levels of security and operational efficiency. SFTP remains a cornerstone of modern secure networking, especially in environments that handle sensitive or regulated information.
Question 150
Which protocol is used to check connectivity between devices and measure response times over an IP network?
A) ICMP
B) TCP
C) SNMP
D) DNS
Answer: A) ICMP
Explanation:
ICMP, or Internet Control Message Protocol, is a network protocol used to check connectivity between devices and measure response times over an IP network. ICMP is a core protocol of the Internet Protocol suite and operates at the network layer (Layer 3) of the OSI model. It provides diagnostic and error-reporting functionality, allowing devices to communicate issues such as unreachable destinations, time exceeded, and redirect messages. ICMP is commonly used in network utilities like ping and traceroute, which help administrators verify connectivity, measure latency, and troubleshoot network issues.
TCP, or Transmission Control Protocol, provides reliable, connection-oriented communication between devices at the transport layer. While TCP is used to deliver data streams, it is not primarily a diagnostic or network connectivity tool. SNMP is used for monitoring and managing devices, collecting metrics, and sending alerts, but it does not measure response times between devices. DNS resolves domain names into IP addresses and does not provide diagnostic functionality or connectivity checks.
ICMP operates by sending messages encapsulated within IP packets. In a ping operation, an ICMP Echo Request message is sent to the target device, which responds with an ICMP Echo Reply. The time taken for the reply provides a measure of round-trip latency. Traceroute uses ICMP Time Exceeded messages to map the path that packets take to reach a destination, helping identify routing issues or network bottlenecks. These tools are essential for maintaining network performance, troubleshooting connectivity problems, and analyzing path behavior in complex networks.
The correct answer is ICMP because it is specifically designed for network diagnostics, connectivity verification, and response-time measurement. Administrators use ICMP-based tools to detect device availability, measure latency, and isolate points of failure. While ICMP can be exploited in certain attacks, such as ping floods or ICMP-based reconnaissance, proper firewall rules and rate-limiting mitigate risks while retaining its diagnostic utility. Understanding ICMP message types, codes, and proper handling is essential for network troubleshooting, performance assessment, and security management.
ICMP remains an integral part of network administration, providing visibility into network paths, response times, and device availability. By monitoring ICMP responses, administrators can proactively detect issues, optimize routing, and verify the operational status of network devices. In enterprise networks, ICMP diagnostics complement other monitoring protocols like SNMP and logging systems to provide a comprehensive view of network health. Proper use of ICMP ensures timely detection of connectivity issues, supports efficient troubleshooting, and maintains the reliability of IP networks.
ICMP is a fundamental protocol for network diagnostics and connectivity verification, enabling administrators to measure response times, detect unreachable hosts, and analyze network paths. Understanding ICMP message types, utility tools, and security considerations allows for effective troubleshooting, performance optimization, and maintenance of reliable and resilient networks. Proper configuration and monitoring ensure that ICMP provides maximum utility without introducing security risks, supporting overall network reliability and operational efficiency.