CompTIA N10-009 Network+ Exam Dumps and Practice Test Questions Set 12 Q166-180
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Question 166
Which network topology connects all devices in a closed loop, where each device is connected to exactly two others and data flows in a single direction?
A) Star
B) Ring
C) Bus
D) Mesh
Answer: B) Ring
Explanation:
Ring topology is a network design in which all devices are connected in a closed loop, with each device connected to exactly two neighboring devices. Data flows in a single direction, either clockwise or counterclockwise, passing through each device until it reaches the intended recipient. This topology can use token-passing mechanisms to control access to the network, where a token circulates the ring, and only the device holding the token can send data. This prevents collisions and provides deterministic network access, which can be important for time-sensitive applications or industrial networks.
Star topology connects devices independently to a central hub or switch, so failure of one device does not affect the others, and data is transmitted via the central node. Bus topology connects all devices along a single shared backbone, where signals are broadcast to all nodes, leading to collisions if multiple devices transmit simultaneously. Mesh topology provides point-to-point connections between every device in the network, offering high redundancy and fault tolerance but requiring extensive cabling and complex configuration.
Ring topology is advantageous in environments where predictable and sequential data delivery is necessary. The token-passing method ensures that only one device can transmit at a time, avoiding collisions that are common in shared-medium networks like bus topology. Data is transmitted in a consistent path, allowing for easier monitoring and troubleshooting. If one device fails in a simple ring, it can disrupt the network, so many implementations include dual rings or bypass mechanisms to maintain connectivity.
The correct answer is ring because it specifically describes a closed-loop network where each device connects to two others and data flows in a single direction. Administrators must ensure proper configuration of the token mechanism, network monitoring, and fault detection to maintain reliable operation. Network performance in ring topologies is generally predictable, and latency can be calculated based on the number of devices and transmission speed.
Ring topology can be implemented in physical or logical designs. Logical ring networks can exist over physical star configurations using switches and specialized protocols that emulate ring behavior. Technologies such as Fiber Distributed Data Interface (FDDI) and Token Ring historically used ring topologies, providing deterministic network access and high-speed data transmission for enterprise environments. Understanding ring topology operation, advantages, and limitations is essential for designing and maintaining networks that require sequential and controlled data flow.
Ring topology provides structured, predictable, and collision-free network communication by connecting devices in a closed loop with single-direction data flow. Proper planning, token management, fault tolerance, and monitoring are necessary for maintaining a reliable network. Ring topology is particularly suited for applications where timing and sequence of transmission are critical, and administrators must understand its characteristics, operational mechanisms, and potential failure points to ensure efficient and stable network performance.
Question 167
Which wireless standard operates in the 5 GHz frequency band and supports data rates up to 1.3 Gbps using multiple antennas?
A) 802.11a
B) 802.11ac
C) 802.11b
D) 802.11g
Answer: B) 802.11ac
Explanation:
802.11ac is a wireless networking standard that operates primarily in the 5 GHz frequency band and supports data rates up to 1.3 Gbps using multiple antennas through MIMO (Multiple Input Multiple Output) technology. It is an evolution of the earlier 802.11n standard, providing higher throughput, wider channels, and improved efficiency in dense wireless environments. 802.11ac uses advanced modulation schemes, such as 256-QAM, to increase data transmission rates and supports beamforming, which focuses the signal toward specific devices for better coverage and reduced interference.
802.11a also operates in the 5 GHz band but supports lower data rates up to 54 Mbps and lacks many of the enhancements provided by 802.11ac. 802.11b operates in the 2.4 GHz band with maximum data rates of 11 Mbps, which is slower and more prone to interference. 802.11g also operates in 2.4 GHz but improves throughput to 54 Mbps; it does not achieve the high speeds, advanced modulation, or MIMO capabilities of 802.11ac.
802.11ac introduces wider channel bandwidths, such as 80 MHz and optional 160 MHz channels, which increase the amount of data transmitted per second. MIMO technology allows multiple antennas to send and receive parallel data streams, enhancing speed and reliability. Beamforming improves signal strength and network performance by directing wireless energy toward clients instead of broadcasting uniformly. These features make 802.11ac ideal for modern high-speed applications, such as video streaming, online gaming, and enterprise environments with multiple connected devices.
The correct answer is 802.11ac because it specifically operates in the 5 GHz band, supports high-speed MIMO transmission, and provides modern wireless enhancements for improved performance and coverage. Network administrators deploying 802.11ac must consider channel planning, interference mitigation, and proper placement of access points to maximize throughput and maintain reliable coverage in both home and enterprise networks.
Security in 802.11ac networks typically involves WPA2 encryption, protecting communication over the air. Advanced features like MU-MIMO (Multi-User MIMO) allow simultaneous communication with multiple clients, increasing efficiency in dense network environments. Compatibility with legacy standards is also a consideration, as dual-band access points may need to serve devices using older 802.11a/b/g/n standards. Understanding the technical capabilities and limitations of 802.11ac ensures optimal network design, performance, and security.
802.11ac provides high-speed wireless connectivity in the 5 GHz band with MIMO and beamforming support. Its advanced modulation, wider channels, and efficient spectrum use make it a leading standard for modern wireless networks. Proper configuration, placement, and security implementation ensure reliable, fast, and secure wireless communication, accommodating the growing demands of contemporary digital environments.
Question 168
Which protocol is used to securely retrieve email from a mail server while leaving a copy on the server for access from multiple devices?
A) POP3
B) IMAP
C) SMTP
D) FTP
Answer: B) IMAP
Explanation:
IMAP, or Internet Message Access Protocol, is a protocol used to securely retrieve email from a mail server while leaving a copy on the server. This enables users to access and manage their email from multiple devices while maintaining synchronization across all devices. IMAP operates over TCP, typically using port 143 for unencrypted connections or port 993 for SSL/TLS encrypted connections. Users can read, delete, or organize emails into folders, and changes are reflected on the server, ensuring consistency for devices accessing the account simultaneously.
POP3, or Post Office Protocol 3, typically downloads emails from the server to a single device and often removes them from the server, making it unsuitable for multi-device synchronization. SMTP is used for sending emails, not retrieving them. FTP is a file transfer protocol and has no role in email retrieval.
IMAP supports multiple folders, message flags, search functionality, and concurrent access from multiple clients. Encryption through SSL/TLS ensures that credentials and message content are protected during transmission. IMAP also allows selective downloading of headers or attachments, reducing bandwidth usage for clients with limited connectivity. These features make IMAP ideal for mobile devices, laptops, and desktop clients that need synchronized access to email.
The correct answer is IMAP because it specifically allows secure retrieval of email while keeping it on the server for multi-device access. Administrators must configure mail servers to support secure IMAP connections, implement proper authentication methods, and enforce encryption policies to prevent unauthorized access. IMAP also integrates with anti-spam, antivirus, and backup systems to ensure reliability and security.
IMAP’s capability to maintain server-based copies of emails supports enterprise collaboration, remote work, and BYOD environments. Organizations can implement policies to manage mailbox sizes, retention periods, and folder structures, optimizing storage and accessibility. Understanding IMAP operation, security considerations, and client configuration is critical for administrators and users to ensure efficient, secure, and synchronized email management.
IMAP enables secure retrieval of emails from a mail server while maintaining server copies, supporting synchronization across multiple devices. Its features, including folder management, selective downloading, and encryption, make it essential for modern email systems. Proper implementation ensures secure, reliable, and efficient communication, accommodating diverse devices and user needs while maintaining centralized control over email data.
Question 169
Which protocol is used to resolve domain names into IP addresses?
A) ICMP
B) ARP
C) DNS
D) DHCP
Answer: C) DNS
Explanation:
DNS, or Domain Name System, is a protocol used to resolve human-readable domain names into IP addresses. DNS operates as a hierarchical, distributed database, allowing clients to query DNS servers to obtain the IP address associated with a specific hostname. This translation is essential because while humans use domain names, network devices communicate using numeric IP addresses. DNS queries can be recursive, where the server queries other servers to resolve a name, or iterative, where the client queries successive servers. DNS can operate over UDP for queries and TCP for zone transfers or large responses.
ICMP is used for network diagnostics, such as ping or traceroute, but does not perform name resolution. ARP maps IP addresses to MAC addresses on a local network, but does not translate hostnames. DHCP dynamically assigns IP addresses but does not provide domain name resolution.
DNS provides multiple record types, including A and AAAA records for host addresses, MX for mail servers, CNAME for canonical names, and PTR for reverse resolution. DNS supports caching, reducing lookup times and network traffic. Security extensions, such as DNSSEC, provide authentication and integrity checks to prevent spoofing and cache poisoning attacks. The correct answer is DNS because it specifically performs the function of translating domain names into IP addresses for network communication.
DNS is foundational for the Internet, enabling web browsing, email delivery, and application connectivity. Administrators must configure authoritative, recursive, and caching DNS servers properly, implement redundancy, and secure them against attacks. Misconfigured DNS can lead to service disruption, inability to resolve addresses, or vulnerability to malicious activity.
DNS resolves domain names into IP addresses, supporting communication between humans and network devices. Proper deployment, security, and management of DNS infrastructure ensure reliable, accurate, and secure network operations.
Question 170
Which technology allows segmentation of a physical network into multiple logical networks within the same switch?
A) NAT
B) VLAN
C) VPN
D) Subnetting
Answer: B) VLAN
Explanation:
VLAN, or Virtual Local Area Network, is a technology that allows segmentation of a physical network into multiple logical networks within the same switch or network infrastructure. VLANs enable administrators to isolate traffic for security, performance, and organizational purposes. Devices within the same VLAN can communicate as if they are on the same physical network, while devices in different VLANs require a router or Layer 3 switch for inter-VLAN communication. VLANs reduce broadcast domains, improve network efficiency, and support logical separation of departments, functions, or security zones within a shared physical network.
NAT translates IP addresses between networks but does not segment physical networks into logical domains. VPN establishes secure connections over untrusted networks but does not create logical networks within a LAN. Subnetting divides an IP address space into smaller networks but does not enforce isolation at the data link layer within a switch.
VLANs use tagging protocols like IEEE 802.1Q to identify traffic belonging to different logical networks and maintain separation as it traverses shared infrastructure. Proper VLAN design includes planning IP address schemes, access control, and trunk configuration for inter-switch connectivity. VLANs enhance security by limiting access to sensitive resources and containing broadcast traffic within designated groups. The correct answer is VLAN because it provides logical segmentation within a physical switch environment.
VLANs support scalability, network management, and efficient use of resources. They are widely used in enterprise networks to isolate traffic, support multi-tenant environments, and enable flexible network designs. Administrators must monitor VLAN assignments, configure trunk ports, and enforce security policies to prevent VLAN hopping or misconfigurations. Understanding VLAN operation, tagging, and interaction with routing and firewall policies is essential for maintaining secure, efficient, and manageable networks.
VLAN technology allows logical segmentation of a physical network into multiple isolated networks within a switch, improving security, efficiency, and manageability. Proper planning, configuration, and monitoring ensure optimal network performance, isolation, and protection against unauthorized access. VLANs are foundational for modern enterprise networking, providing flexible and secure logical network design on shared physical infrastructure.
Question 171
Which device is used to connect multiple network segments and filter traffic based on MAC addresses?
A) Router
B) Switch
C) Hub
D) Firewall
Answer: B) Switch
Explanation:
A switch is a network device used to connect multiple devices within a local area network (LAN) and forward frames based on MAC addresses. It operates at Layer 2 of the OSI model and maintains a MAC address table that maps device addresses to physical ports. When a frame arrives, the switch examines the destination MAC address and forwards the frame only to the specific port associated with that address, minimizing unnecessary network traffic and reducing collisions compared to a hub. Switches can operate in full-duplex mode, allowing simultaneous transmission and reception of data, which increases network efficiency and performance.
Routers operate at Layer 3 and forward packets based on IP addresses, connecting different networks rather than segments within the same LAN. Hubs operate at Layer 1 and broadcast incoming signals to all connected devices, lacking intelligence for filtering traffic. Firewalls inspect traffic to enforce security policies but are not primarily designed to forward frames based on MAC addresses within a LAN.
Switches improve network efficiency and security by segmenting collision domains for each port, unlike hubs that share a single collision domain. Managed switches provide additional capabilities, such as VLANs, port mirroring, QoS, link aggregation, and monitoring for network management. Unmanaged switches are simpler and suitable for small networks, automatically learning MAC addresses and forwarding traffic appropriately.
The correct answer is switch because it specifically filters traffic based on MAC addresses and forwards frames to the appropriate ports. Administrators must configure switches correctly, including VLANs, port security, and redundancy mechanisms such as Spanning Tree Protocol (STP), to prevent loops and ensure optimal performance. Security measures such as MAC filtering, access control lists, and port security help protect against unauthorized devices and reduce risks of network attacks.
Switches are essential in modern networks, connecting computers, printers, access points, and other devices efficiently. They support high-speed communication, reduce congestion, and provide a platform for advanced network features. Layer 3 switches combine traditional switching with routing capabilities, enabling inter-VLAN communication without requiring an external router. Understanding switch operation, MAC address learning, frame forwarding, and advanced features is critical for network administrators to design and maintain reliable and scalable LANs.
Switches are fundamental devices that connect multiple devices within a LAN and forward traffic based on MAC addresses. They improve network efficiency, security, and scalability. Proper deployment and configuration ensure effective communication, reduced collisions, and controlled access, making switches indispensable components of modern networks.
Question 172
Which protocol is used for secure web browsing by encrypting HTTP traffic?
A) FTP
B) HTTPS
C) Telnet
D) SNMP
Answer: B) HTTPS
Explanation:
HTTPS, or Hypertext Transfer Protocol Secure, is a protocol that encrypts HTTP traffic between a client and a web server, ensuring confidentiality, integrity, and authentication. It uses Transport Layer Security (TLS) or the older Secure Sockets Layer (SSL) to encrypt communication, protecting sensitive data such as login credentials, financial information, and personal details from interception or tampering. HTTPS operates over TCP port 443, providing a secure channel for web browsing, online transactions, and communication with web-based applications.
FTP is used for file transfer and does not inherently encrypt data unless combined with secure variants like FTPS or SFTP. Telnet provides remote command-line access but transmits data in plaintext, making it insecure. SNMP is used for network management and monitoring, and does not encrypt regular web traffic.
HTTPS provides three primary security guarantees: encryption to protect data in transit, authentication through server certificates to verify the legitimacy of the server, and integrity to ensure that data is not altered during transmission. Modern browsers indicate HTTPS connections with a padlock icon and enforce warnings when certificates are invalid or connections are insecure. HTTPS also supports forward secrecy, preventing decryption of captured data even if private keys are compromised later.
The correct answer is HTTPS because it specifically encrypts HTTP traffic, protecting web communications from eavesdropping, tampering, and impersonation attacks. Administrators must configure web servers with valid TLS certificates, strong cipher suites, and protocols to ensure secure communication. Regular updates, monitoring, and enforcement of HTTPS on websites improve security posture and user trust.
HTTPS is critical for online banking, e-commerce, email services, and cloud applications where sensitive information is exchanged. Enforcing HTTPS, implementing HSTS (HTTP Strict Transport Security), and monitoring certificate expiration are essential practices for network security. Understanding HTTPS operation, certificate management, encryption methods, and potential vulnerabilities is crucial for ensuring secure web communications and protecting both organizations and users from cyber threats.
HTTPS is the standard protocol for secure web browsing, providing encryption, authentication, and integrity for HTTP traffic. Proper implementation, certificate management, and continuous monitoring ensure secure communication, prevent data interception, and protect sensitive information in online environments. HTTPS remains an essential element of modern network security, enabling trust and confidentiality in digital interactions.
Question 173
Which IP address class provides 65,534 usable host addresses per network?
A) Class A
B) Class B
C) Class C
D) Class D
Answer: B) Class B
Explanation:
Class B IP addresses are part of the traditional IPv4 addressing scheme and provide 65,534 usable host addresses per network. Class B addresses have a default subnet mask of 255.255.0.0, with the first two octets representing the network portion and the last two octets representing the host portion. This addressing allows for 16,384 networks with up to 65,534 hosts per network, supporting medium-to-large organizations that require a significant number of IP addresses within a single network.
Class A addresses have a default subnet mask of 255.0.0.0, allowing 16,777,214 usable hosts but fewer networks. Class C addresses have a default subnet mask of 255.255.255.0, providing 254 usable hosts per network, suitable for smaller networks. Class D addresses are reserved for multicast traffic and do not provide host addresses for standard network devices.
Class B addresses are used in enterprise environments, large campuses, and service provider networks where a substantial number of hosts must coexist within the same network segment. Network administrators must plan addressing carefully, including subnetting Class B networks to optimize address utilization, improve performance, and reduce broadcast domain size. Subnetting allows splitting a Class B network into smaller segments, maintaining hierarchical addressing and simplifying routing.
The correct answer is Class B because it provides 65,534 usable host addresses per network, making it suitable for large-scale networks. Administrators must consider IP assignment, subnetting, and routing protocols to manage Class B networks efficiently and prevent address exhaustion or misconfiguration. Understanding the characteristics, advantages, and limitations of Class B addressing is essential for designing scalable and organized IP networks.
Class B addresses provide a balance between network size and host capacity, allowing large networks to accommodate thousands of devices while maintaining hierarchical organization and routing efficiency. Proper planning, subnetting, and management ensure optimal utilization, reduced network congestion, and maintainable network architecture, making Class B addresses critical in medium-to-large enterprise networks.
Question 174
Which protocol is used to encrypt file transfers over a network, ensuring confidentiality and integrity?
A) SFTP
B) FTP
C) Telnet
D) TFTP
Answer: A) SFTP
Explanation:
SFTP, or Secure File Transfer Protocol, is a protocol used to encrypt file transfers over a network, ensuring both confidentiality and integrity. SFTP operates over an encrypted SSH session, providing secure authentication, encrypted data transmission, and protection against eavesdropping or tampering. Unlike FTP, which sends credentials and data in plaintext, SFTP ensures that sensitive information such as files, passwords, and configuration data remains protected. SFTP can operate on the same port as SSH, typically port 22, and supports commands for file upload, download, directory listing, and permissions management securely.
FTP transfers files without encryption, exposing credentials and data to interception. Telnet provides remote access but is unencrypted, and TFTP is a lightweight protocol for simple file transfers without authentication or encryption, making it insecure.
SFTP supports authentication using passwords, SSH keys, or a combination of both, enhancing security in enterprise and remote operations. Administrators can implement access controls, logging, and monitoring to track file transfer activity and detect unauthorized attempts. SFTP ensures data integrity using encryption and checksums, preventing modification during transmission.
The correct answer is SFTP because it encrypts file transfers, ensuring confidentiality and integrity. Proper configuration, secure key management, and monitoring are critical for maintaining secure file transfer operations. SFTP is widely used for backups, system updates, and secure exchange of sensitive data between clients and servers. It integrates with automation scripts, enterprise systems, and secure workflows, providing reliable, auditable, and encrypted file management.
SFTP provides encrypted, secure, and reliable file transfer over networks. By leveraging SSH for authentication and encryption, SFTP ensures that data remains confidential and intact during transmission. Understanding SFTP operation, authentication mechanisms, and security practices is essential for administrators to maintain a secure file transfer infrastructure and protect sensitive information in modern network environments.
Question 175
Which protocol is commonly used to test connectivity and measure round-trip time between devices on a network?
A) ICMP
B) DNS
C) ARP
D) SMTP
Answer: A) ICMP
Explanation:
ICMP, or Internet Control Message Protocol, is commonly used to test connectivity and measure round-trip time between devices on a network. ICMP provides feedback about network issues, errors, or operational status by sending messages such as echo requests and receiving echo replies, commonly implemented in the ping utility. Network administrators use ICMP to verify device availability, troubleshoot routing issues, and measure latency between endpoints. ICMP also generates error messages for unreachable hosts, time exceeded in transit, or packet fragmentation requirements, helping diagnose and correct network problems.
DNS translates domain names to IP addresses, but does not provide connectivity testing. ARP resolves IP addresses to MAC addresses within a local network and cannot measure round-trip time. SMTP is used for sending email, not network diagnostics.
ICMP operates at the network layer and is supported by most networking devices, including routers, switches, and servers. Administrators can use ICMP for network mapping, determining latency, and identifying packet loss. Firewalls and security devices often control ICMP traffic to prevent abuse, such as denial-of-service attacks, while allowing legitimate network testing.
The correct answer is ICMP because it specifically provides connectivity testing and round-trip time measurement. Proper use includes controlled testing, monitoring network performance, and detecting issues before they impact production systems. ICMP provides vital feedback for troubleshooting network routing, latency, packet loss, and host reachability.
ICMP is a fundamental protocol for network diagnostics, connectivity verification, and performance measurement. Understanding its capabilities, limitations, and secure deployment is essential for effective network management, problem detection, and performance optimization in modern networking environments.
Question 176
Which technology allows a single physical network interface to support multiple VLANs?
A) Trunking
B) NAT
C) Port mirroring
D) Subnetting
Answer: A) Trunking
Explanation:
Trunking is a networking technology that allows a single physical network interface to carry traffic for multiple VLANs. This technique is commonly implemented on switches using protocols such as IEEE 802.1Q, which inserts a VLAN tag into Ethernet frames to identify the VLAN to which each frame belongs. Trunking enables devices like routers, switches, and servers to communicate with multiple VLANs through one physical connection, reducing cabling requirements and improving network efficiency. In a typical network, access ports connect end devices to a single VLAN, while trunk ports carry multiple VLANs between networking devices or to devices capable of handling tagged traffic.
NAT, or Network Address Translation, translates private IP addresses to public IP addresses for Internet communication but does not segment VLANs or transmit multiple VLANs over a single interface. Port mirroring duplicates traffic from one port to another for monitoring and analysis purposes and is not designed to carry multiple VLANs. Subnetting divides an IP address space into smaller segments for network organization and routing efficiency, but it does not involve carrying multiple VLANs over a single physical link.
Trunking is essential in modern enterprise networks, where network segmentation is required for security, performance, and organizational purposes. It allows multiple VLANs to traverse a single link between switches or from a switch to a router performing inter-VLAN routing. By using VLAN tags, devices at the receiving end can identify the correct VLAN for each frame and forward it accordingly. Trunking supports high-speed network infrastructure and reduces physical cabling requirements, simplifying network management while maintaining logical separation of traffic.
The correct answer is trunking because it specifically allows one physical interface to carry traffic for multiple VLANs, enabling efficient communication and resource usage across segmented networks. Administrators must configure trunk ports properly, define allowed VLANs, and ensure consistency on both ends of the trunk link to prevent miscommunication or traffic loss. Trunking also supports link aggregation, enabling multiple trunk links to provide higher throughput and redundancy.
Trunking is widely used in scenarios such as connecting core switches to distribution switches, linking access layer switches to data center devices, and integrating servers with virtualized network interfaces. Protocols like 802.1Q provide a standardized method for VLAN tagging and compatibility between different vendor equipment. Misconfigurations can lead to VLAN leaks, broadcast storms, or dropped traffic, so administrators must monitor trunk links and implement best practices for security and reliability.
The benefits of trunking include reduced physical cabling, support for multiple logical networks over shared infrastructure, simplified network management, and consistent application of policies across VLANs. By combining trunking with VLANs, administrators can create isolated network segments for different departments, security zones, or applications, maintaining performance and security while using shared physical resources. Understanding trunking operation, VLAN tagging, and inter-VLAN communication is crucial for designing and maintaining scalable, efficient, and secure enterprise networks.
Trunking allows a single physical network interface to carry multiple VLANs efficiently. It uses tagging protocols like 802.1Q to identify traffic, supports logical segmentation, simplifies cabling, and enables high-speed communication between network devices. Proper configuration, monitoring, and security measures ensure optimal performance, isolation, and reliability, making trunking an essential component of modern VLAN-based networks.
Question 177
Which device connects multiple networks and makes forwarding decisions based on IP addresses?
A) Switch
B) Hub
C) Router
D) Access Point
Answer: C) Router
Explanation:
A router is a networking device that connects multiple networks and makes forwarding decisions based on IP addresses. Operating at Layer 3 of the OSI model, a router examines the destination IP address of a packet and uses routing tables and protocols to determine the best path for delivery to another network. Routers can connect local networks to wide area networks, the Internet, or other segments within an enterprise. They perform functions such as packet forwarding, network address translation, access control, and sometimes advanced features like VPN termination or QoS enforcement.
Switches operate at Layer 2 and forward frames based on MAC addresses within the same LAN segment but do not make forwarding decisions between networks using IP addresses. Hubs operate at Layer 1 and broadcast traffic to all ports without considering addressing, offering no intelligence for routing. Access points provide wireless connectivity to clients but typically do not perform routing functions between networks.
Routers use static or dynamic routing to determine the best path for packets. Static routes are manually configured by administrators, whereas dynamic routing protocols such as OSPF, EIGRP, or BGP allow routers to exchange routing information and adjust paths based on network changes. Routers also support NAT to translate private IP addresses for Internet connectivity, providing security and conserving public IP address space. Firewall functions or ACLs on routers can enforce policies that control which traffic is allowed between networks, further enhancing security.
The correct answer is router because it specifically connects multiple networks and forwards packets based on IP addressing. Proper configuration involves defining routing protocols, addressing schemes, interface settings, and security policies. Routers can be physical devices, virtual appliances, or software implementations within a network operating system. Administrators must monitor routing tables, update protocols, and ensure redundancy to prevent failures that could impact communication across networks.
Routers play a critical role in network segmentation, inter-VLAN communication, Internet access, and VPN connectivity. They facilitate efficient delivery of data across multiple networks, optimize paths for performance, and prevent routing loops. By supporting features such as dynamic routing, NAT, VPNs, firewalling, and QoS, routers provide comprehensive connectivity and control in enterprise and service provider networks. Understanding router functionality, protocols, and deployment strategies is essential for building scalable, secure, and reliable network infrastructures.
Routers connect multiple networks and make forwarding decisions based on IP addresses. They support dynamic and static routing, interconnect diverse network segments, and provide essential security, NAT, and optimization features. Proper configuration and maintenance ensure effective communication, redundancy, and security, making routers a cornerstone of modern networking infrastructure. Administrators must understand routing principles, address schemes, and protocol operation to maximize network performance and reliability.
Question 178
Which protocol provides secure remote command-line access to network devices over an encrypted connection?
A) Telnet
B) SSH
C) FTP
D) RDP
Answer: B) SSH
Explanation:
SSH, or Secure Shell, is a protocol that provides secure remote command-line access to network devices over an encrypted connection. SSH operates at the application layer and relies on TCP, typically using port 22. It ensures confidentiality, integrity, and authentication by encrypting all data transmitted between the client and server, protecting sensitive information such as usernames, passwords, and configuration commands from interception or tampering. SSH supports public key and password-based authentication, providing flexibility and enhanced security for administrators accessing switches, routers, firewalls, or servers remotely.
Telnet is an older protocol that provides remote command-line access but transmits all data in plaintext, making it vulnerable to interception, eavesdropping, and credential theft. FTP is used for transferring files between devices and does not provide command-line access or secure encryption for administrative purposes. RDP, or Remote Desktop Protocol, provides graphical remote access to Windows systems but is not typically used for command-line management of network devices.
SSH provides additional features, including secure file transfer via SCP or SFTP, port forwarding to create encrypted tunnels for other protocols, and secure automation of network management tasks using scripts. Administrators can configure SSH to allow only trusted clients, enforce strong encryption algorithms, and limit access based on IP addresses or roles. Using SSH instead of Telnet is considered a fundamental security best practice in modern networks, reducing the risk of credential compromise and unauthorized access.
The correct answer is SSH because it specifically provides secure, encrypted command-line access for network administration. Proper implementation involves generating cryptographic keys, configuring access controls, disabling legacy insecure protocols, and monitoring logs for suspicious activity. SSH also supports session management features such as key rotation, idle timeouts, and logging of executed commands for auditing purposes.
SSH is widely adopted in enterprise, data center, and cloud environments for managing networking devices, servers, and virtual infrastructure. It ensures administrators can maintain operational control securely, even over untrusted networks such as the Internet or public connections. By encrypting both authentication and session data, SSH protects against man-in-the-middle attacks, password sniffing, and replay attacks. Understanding SSH operation, encryption mechanisms, and secure deployment practices is essential for network administrators to maintain a secure and efficient management infrastructure.
SSH supports multiple encryption and hashing algorithms, ensuring compatibility and security across diverse environments. Administrators can enforce strict protocol versions and algorithm suites to meet organizational security policies and compliance requirements. SSH also integrates with centralized authentication systems, such as RADIUS or LDAP, enabling role-based access and simplifying credential management across multiple devices. By replacing Telnet with SSH, organizations significantly improve the confidentiality, integrity, and reliability of remote network administration.
SSH provides secure, encrypted remote command-line access to network devices, offering authentication, confidentiality, and integrity for administrative sessions. Proper configuration, strong encryption, key management, and monitoring practices ensure that network management remains secure, preventing unauthorized access and protecting sensitive information. SSH has become the standard for secure remote administration, enabling network administrators to manage devices efficiently while maintaining the highest security standards across modern networking environments.
Question 179
Which wireless security protocol is considered the least secure and should be avoided in modern networks?
A) WPA2
B) WEP
C) WPA3
D) WPA
Answer: B) WEP
Explanation:
WEP, or Wired Equivalent Privacy, is an outdated wireless security protocol that is considered the least secure and should be avoided in modern networks. WEP was originally designed to provide encryption for wireless networks using the RC4 stream cipher and a 40- or 104-bit key. However, WEP has numerous vulnerabilities, including weak key generation, easily predictable initialization vectors, and lack of proper message integrity checks, which make it highly susceptible to attacks. Attackers can recover WEP keys using publicly available tools within minutes, gaining unauthorized access to wireless networks and potentially intercepting sensitive traffic.
WPA2, or Wi-Fi Protected Access 2, provides strong encryption using AES and CCMP, making it far more secure than WEP. WPA3 is the latest wireless security standard, offering enhanced encryption, forward secrecy, and protections against brute-force attacks. WPA, the predecessor to WPA2, uses TKIP, which is more secure than WEP but still less robust than AES-based WPA2.
WEP’s vulnerabilities are primarily due to its weak initialization vectors and RC4 key reuse, which allow attackers to capture enough packets to recover the encryption key. Additionally, WEP does not provide sufficient authentication or integrity verification, enabling attackers to inject malicious packets or impersonate authorized clients. Modern wireless security standards have addressed these shortcomings with stronger encryption algorithms, better key management, and advanced authentication mechanisms.
The correct answer is WEP because it is inherently insecure and no longer recommended for use. Network administrators should replace WEP with WPA2 or WPA3 to ensure strong encryption, data integrity, and secure access controls. WPA2 with AES provides robust encryption for existing devices, while WPA3 introduces forward secrecy, protecting past communications even if current keys are compromised. Transitioning away from WEP involves updating access points, client devices, and network policies to support modern encryption and authentication standards.
WEP’s weaknesses make networks vulnerable to unauthorized access, data interception, and injection attacks. Organizations that continue to use WEP risk exposure to man-in-the-middle attacks, theft of sensitive information, and network compromise. Security best practices recommend auditing wireless networks, identifying WEP-enabled devices, and migrating them to WPA2 or WPA3 to ensure compliance and mitigate risks. Understanding WEP vulnerabilities and modern alternatives is crucial for maintaining secure wireless environments.
WEP is the least secure wireless security protocol and should be avoided in modern networks due to its weak encryption, predictable keys, and lack of integrity mechanisms. Replacing WEP with WPA2 or WPA3 ensures secure communication, prevents unauthorized access, and protects sensitive information transmitted over wireless networks. Proper planning, deployment, and monitoring of modern wireless security protocols are essential for maintaining a secure, reliable, and resilient network infrastructure.
Question 180
Which network device operates at Layer 3 of the OSI model and can segment networks while providing inter-VLAN routing?
A) Switch
B) Router
C) Hub
D) Bridge
Answer: B) Router
Explanation:
A router is a network device that operates at Layer 3 of the OSI model, known as the network layer, and is primarily responsible for forwarding packets between different networks based on IP addresses. Unlike switches that forward frames within the same LAN based on MAC addresses, routers analyze the destination IP of a packet and use routing tables to determine the optimal path to deliver it. In addition to connecting different networks, routers can perform inter-VLAN routing, which allows devices in separate VLANs on a switched network to communicate with each other through the router. This capability is critical in segmented enterprise networks where VLANs provide security, traffic separation, and organizational efficiency.
Switches operate mainly at Layer 2, forwarding frames based on MAC addresses, and do not inherently provide routing between networks. Hubs function at Layer 1, broadcasting data to all ports without any filtering, routing, or segmentation capability. Bridges operate at Layer 2 and can segment collision domains by connecting two LAN segments, but they lack the Layer 3 intelligence required for inter-network routing. Routers, therefore, are the correct choice because they provide the routing functionality that bridges, hubs, and basic switches cannot perform.
Inter-VLAN routing is a key feature provided by routers in modern enterprise networks. Each VLAN represents a distinct logical network segment with its own IP subnet. Devices within the same VLAN can communicate freely at Layer 2, but communication across VLANs requires Layer 3 intervention. Routers or Layer 3 switches perform this function by routing packets between subnets while enforcing policies such as access control lists (ACLs), quality of service (QoS), and network security measures. Properly configured inter-VLAN routing ensures that network segmentation improves performance and security without isolating necessary communication paths.
Routers use static routes, manually configured by administrators, or dynamic routing protocols like OSPF, EIGRP, BGP, or RIP to determine the best path for forwarding packets. Dynamic routing allows routers to adapt to network topology changes, detect failures, and automatically update routing tables to maintain optimal paths. In addition to basic routing, routers often provide services such as network address translation (NAT), firewall functions, VPN termination, and traffic prioritization. These features make routers indispensable for managing large, complex, and secure networks.
The correct answer is router because it uniquely combines the ability to segment networks and route traffic based on IP addresses, enabling communication across VLANs and different networks. Routers are essential for connecting LANs to wide area networks (WANs) and providing access to the Internet, cloud services, and remote networks. They maintain routing tables that contain information about network paths and can calculate the shortest or most efficient path to deliver packets. Administrators must carefully plan IP addressing, routing policies, and inter-VLAN configurations to ensure consistent and efficient network operation.
Routers also enhance network security by enforcing policies that control traffic between VLANs, networks, and external connections. Access control lists can block unauthorized traffic, permit only specific protocols, and filter packets based on source or destination IP addresses. Many modern routers include intrusion detection and prevention systems to detect malicious activity and prevent attacks. Additionally, routers can segment traffic to prioritize critical applications or manage bandwidth usage, supporting high-performance and resilient network infrastructure.
Routers operate in a variety of network environments, from small office setups to enterprise data centers and service provider networks. They are used to connect branch offices, support virtual private networks (VPNs) for remote workers, and integrate with firewall appliances to enforce security policies. Routers can be physical hardware devices or virtual appliances running on servers or cloud infrastructure, providing flexibility in deployment and scaling. Understanding router operation, routing protocols, inter-VLAN routing, and policy configuration is essential for network administrators to maintain secure, efficient, and reliable network connectivity.
Routers are Layer 3 devices that provide network segmentation, inter-VLAN routing, and connectivity between different networks. By analyzing IP addresses and making forwarding decisions based on routing tables, routers ensure communication across subnets and improve network performance and security. They support features like NAT, VPNs, ACLs, and QoS, enabling administrators to design scalable, secure, and resilient networks. Proper configuration and maintenance of routers are essential for maintaining optimal network performance, enabling inter-VLAN communication, and securing enterprise networks from unauthorized access or disruptions. Routers remain fundamental devices in modern networking, bridging the gap between segmented LANs, wide-area networks, and Internet connectivity, ensuring efficient and secure data delivery across complex infrastructures.