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Question 81

What is the primary purpose of the default gateway?

1. Encrypting payload data across insecure wireless local networks.
2. Translating private internal IP addresses into public routable addresses.
3. Forwarding packets destined for remote networks outside the local segment.
4. Dynamically assigning configuration parameters to client workstations on demand.

Correct Answer: 3

Explanation:

The default gateway is a critical routing device, typically a router or multilayer switch, configured on a host to handle outbound traffic destined for networks outside the local subnet. When an end device needs to communicate with an IP address that resides on a different logical network, it cannot deliver the packet directly using Layer 2 MAC addresses. Instead, the host encapsulates the packet inside an Ethernet frame addressed to the hardware MAC address of the default gateway. The gateway receives the packet, strips the Layer 2 header, evaluates the Layer 3 destination IP address against its routing table, and forwards the packet toward its ultimate destination across wide area links or enterprise core routers.

Question 82

Which protocol uses broadcast frames for network host discovery?

1. Address Resolution Protocol
2. Transmission Control Protocol
3. Secure Shell Protocol
4. Network Time Protocol

Correct Answer: 1

Explanation:

The Address Resolution Protocol relies heavily on broadcast frames to discover the physical hardware MAC address associated with a known target IPv4 address on a local network segment. When a host needs to communicate with another device but lacks its MAC address in the local ARP cache, it generates an ARP request packet. Because the sender does not yet know the exact hardware address of the receiver, it encapsulates the request inside a Layer 2 broadcast frame using the destination MAC address of all binary ones. This broadcast ensures that every device on the local network segment receives, processes, and evaluates the query.

Question 83

What cable type uses standardized RJ-45 modular connectors?

1. Fiber Optic Patch Cable
2. Coaxial Television Cable
3. Serial Console Rollover Cable
4. Unshielded Twisted Pair Cable

Correct Answer: 4

Explanation:

Unshielded Twisted Pair and shielded twisted pair copper cables used in standard Ethernet local area networks are terminated with modular eight-position, eight-contact connectors commonly referred to as RJ-45 plugs. These connectors feature precision alignment channels that secure each of the four twisted wire pairs in proper sequence according to TIA/EIA 568A or 568B wiring standards. The secure locking tab design ensures reliable physical retention within switch ports, router interfaces, and computer network interface cards, maintaining stable electrical contact for high-speed data transmission up to one hundred meters.

Question 84

Which IPv6 address type is globally routable across the internet?

1. Link-Local Address
2. Global Unicast Address
3. Unique Local Address
4. Multicast Address

Correct Answer: 2

Explanation:

A Global Unicast Address in IPv6 is equivalent to a public IPv4 address, designed to be globally unique and fully routable across the global internet infrastructure. These addresses typically start with the designated prefix 2000::/3, allocated by Internet Assigned Numbers Authority down to regional registries and Internet Service Providers. Global unicast addresses enable end-to-end direct connectivity between devices across public networks without requiring Network Address Translation mechanisms, facilitating streamlined peer-to-peer communication, cloud service access, and transparent routing in modern IPv6 enterprise architectures.

Question 85

What is the primary function of a network bridge?

1. Routing packets across disparate wide area network boundaries.
2. Encrypting management traffic over insecure remote Telnet sessions.
3. Connecting multiple local network segments while filtering frame traffic.
4. Dynamically leasing IP addresses to client workstations on demand.

Correct Answer: 3

Explanation:

A network bridge is a legacy Layer 2 networking device designed to connect two or more separate local network segments into a single unified broadcast domain. Unlike simple hubs that broadcast all electrical signals indiscriminately, a bridge examines the source and destination MAC addresses of incoming Ethernet frames and builds an internal filtering database. By tracking which devices reside on which segment, the bridge forwards frames selectively only to the appropriate segment where the destination host is located, reducing unnecessary traffic congestion and improving overall network efficiency.

Question 86

Which command displays dynamically learned ARP table entries on routers?

1. show ip arp
2. show ip route
3. show interfaces brief
4. show running-config

Correct Answer: 1

Explanation:

The show ip arp command is an essential diagnostic tool executed within the Cisco IOS command-line interface to inspect the router’s current Address Resolution Protocol cache table. When entered in privileged EXEC mode, it lists all resolved IPv4-to-MAC address mappings, associated interface names, hardware connection types, and time-out age counters. Network engineers rely on this command during troubleshooting sessions to verify whether a router or switch can successfully resolve local hardware addresses, identify duplicate IP address conflicts, and confirm Layer 2 connectivity with neighboring hosts.

Question 87

What path selection metric is utilized natively by OSPF?

1. Hop Count
2. Bandwidth and Delay
3. Reliability and Load
4. Cumulative Cost based on Link Bandwidth

Correct Answer: 4

Explanation:

Open Shortest Path First is a link-state routing protocol that utilizes a sophisticated cost metric derived from interface bandwidth to determine the optimal path to a destination network. Unlike distance-vector protocols that rely on hop counts, OSPF calculates cost inversely proportional to reference bandwidth divided by interface bandwidth. By default, Cisco routers assign a reference bandwidth of 100 Mbps, meaning Fast Ethernet and Gigabit interfaces require bandwidth reference adjustments to prevent metric calculation bottlenecks. This cost accumulation allows OSPF to choose superior high-speed links over slower connections.

Question 88

Which OSI layer handles end-to-end flow control and reliability?

1. Network Layer
2. Transport Layer
3. Presentation Layer
4. Physical Layer

Correct Answer: 2

Explanation:

The Transport layer, which is Layer 4 of the OSI reference model, is fundamentally responsible for providing reliable, transparent, and error-checked end-to-end data delivery between communicating hosts. Protocols operating at this layer, such as Transmission Control Protocol, establish connection-oriented sessions, implement flow control mechanisms, utilize windowing to optimize bandwidth utilization, and perform error detection and retransmission of lost segments. This ensures that application data streams are delivered accurately, in correct sequence, and without corruption regardless of the underlying physical network infrastructure traversed.

Question 89

What is the broadcast address for subnet 10.0.0.0 with mask 255.255.255.0?

1. 10.0.0.0
2. 10.0.0.1
3. 10.0.0.255
4. 10.255.255.255

Correct Answer: 3

Explanation:

In any standard IPv4 subnet, the network identifier is represented by setting all host bits to zero, while the broadcast address is represented by setting all host bits to binary ones. For the network 10.0.0.0 with a subnet mask of 255.255.255.0, the first three octets represent the network portion and remain fixed. The final octet represents the host portion, which contains eight bits. Setting all eight host bits to binary ones results in decimal 255, establishing 10.0.0.255 as the broadcast address utilized to reach all devices on that specific subnet segment.

Question 90

Which TCP flag aborts and resets a broken connection immediately?

1. RST
2. SYN
3. FIN
4. ACK

Correct Answer: 1

Explanation:

The Reset flag in the Transmission Control Protocol header is utilized to abort an active connection immediately when a critical error, invalid packet sequence, or unexpected segment arrival occurs. Unlike a graceful teardown initiated by FIN flags, an RST packet tears down the session instantly without waiting for acknowledgments, releasing allocated memory buffers and port resources on both communicating hosts. Network devices and firewalls also utilize RST flags to reject unauthorized connection attempts or signal that a requested port is closed on a target server.

Question 91

What is the primary role of a multilayer switch in enterprise networks?

1. Encrypting wireless data frames against unauthorized eavesdropping.
2. Amplifying weak electrical signals across long coaxial cable runs.
3. Automatically assigning dynamic IP address leases to client workstations.
4. Performing both high-speed Layer 2 switching and Layer 3 routing.

Correct Answer: 4

Explanation:

A multilayer switch is an advanced enterprise networking device capable of performing traditional Layer 2 data link frame switching as well as Layer 3 network layer packet routing within a single hardware platform. By utilizing specialized Application-Specific Integrated Circuits, multilayer switches can process inter-VLAN routing at wire speeds without incurring the latency traditionally associated with external standalone routers. This makes them ideal for core and distribution layers of enterprise campus networks where high-density port connectivity, rapid packet forwarding, and scalable routing performance are required.

Question 92

Which command erases startup configuration memory on Cisco devices?

1. erase running-config
2. write erase
3. format flash memory
4. reload system config

Correct Answer: 2

Explanation:

The write erase command, or its equivalent modern syntax erase startup-config, is executed in privileged EXEC mode within the Cisco IOS command-line interface to delete the startup configuration file stored in non-volatile random-access memory. When a network device is decommissioned, repurposed, or prepared for a fresh configuration lab, executing this command ensures that all previously saved routing parameters, interface settings, passwords, and access control lists are permanently removed from NVRAM. Following this command, administrators typically reboot the device to ensure a completely factory-default operational state.

Question 93

What protocol translates numerical IP addresses into domain names?

1. Dynamic Host Configuration Protocol
2. Address Resolution Protocol
3. Domain Name System
4. Simple Network Management Protocol

Correct Answer: 3

Explanation:

The Domain Name System is a hierarchical and decentralized naming system used to translate human-readable fully qualified domain names into numerical IPv4 or IPv6 addresses, and conversely, to perform reverse lookups translating numerical IP addresses back into domain names. While forward lookups are used for standard host connection routing, reverse DNS lookups are critical for security logging, email server authentication, and network diagnostic tools like traceroute, which resolve router IP addresses into descriptive hostnames to clarify network path analysis reports.

Question 94

Which cable category supports native Gigabit Ethernet transmission?

1. Category 5e
2. Category 3
3. Category 2
4. Category 1

Correct Answer: 1

Explanation:

Category 5e and higher unshielded twisted pair copper cabling standards are engineered to support native Gigabit Ethernet data transmission speeds up to 1000 Mbps over distances up to 100 meters. Category 5e improves upon legacy Category 5 specifications by introducing stricter performance standards for near-end crosstalk, attenuation, and return loss, utilizing all four wire pairs simultaneously for bidirectional data transfer. In contrast, older Category 3 cables were limited to 10 Mbps Ethernet speeds, making Category 5e the baseline standard for modern enterprise wired local area networks.

Question 95

What is the function of the hello packet in OSPF routing operations?

1. Encrypting routing update tables against unauthorized interception.
2. Translating private IP addresses into public routable addresses.
3. Automatically assigning dynamic IP leases to client workstations.
4. Discovering neighbor routers and maintaining bidirectional adjacencies.

Correct Answer: 4

Explanation:

In Open Shortest Path First routing protocols, hello packets serve as lightweight multicast packets transmitted periodically across network interfaces to discover neighboring routers, establish communication parameters, and maintain active adjacencies. Hello packets contain vital configuration details such as hello intervals, dead timers, area identifiers, and router IDs. If a router fails to receive hello packets from an adjacent peer within the designated dead interval timer threshold, OSPF declares the neighbor down and immediately triggers a topology recalculation to route traffic around the failed link.

Question 96

Which OSI layer performs logical addressing and path determination?

1. Data Link Layer
2. Network Layer
3. Transport Layer
4. Session Layer

Correct Answer: 2

Explanation:

The Network layer, which is Layer 3 of the OSI reference model, is fundamentally responsible for logical addressing, path determination, and packet forwarding across disparate internetworks. Protocols operating at this layer, such as IPv4 and IPv6, assign unique logical addresses to host interfaces and utilize routing tables to determine the most efficient path for data packets to travel from source to destination. By abstracting physical hardware details, the network layer enables seamless internetwork communication across heterogeneous physical media types and complex routing topologies.

Question 97

What command shows current interface traffic statistics and error counts?

1. show ip route
2. show running-config
3. show interfaces
4. show ip arp

Correct Answer: 3

Explanation:

The show interfaces command is a comprehensive diagnostic utility executed within the Cisco IOS command-line interface to inspect detailed operational statistics for physical and logical interfaces on a router or switch. When run in privileged EXEC mode, it displays metrics including interface line and protocol status, current bandwidth utilization, input and output packet counters, cyclic redundancy check errors, frame check sequence failures, runts, giants, and buffer drop statistics. Network engineers rely heavily on this command to diagnose physical layer cable degradation, duplex mismatches, and interface congestion.

Question 98

Which protocol operates over UDP ports 67 and 68?

1. Dynamic Host Configuration Protocol
2. Domain Name System
3. Simple Network Management Protocol
4. Trivial File Transfer Protocol

Correct Answer: 1

Explanation:

The Dynamic Host Configuration Protocol utilizes User Datagram Protocol ports 67 and 68 for server-client communications during IP address assignment workflows. UDP port 67 is designated for the server daemon to listen for incoming client configuration requests, while UDP port 68 is assigned to the client workstation to receive lease offers, acknowledgments, and network parameter updates. Because client devices do not yet possess an assigned IP address when initially connecting to the network, DHCP utilizes broadcast messaging across these UDP ports to establish initial communication.

Question 99

What is the primary purpose of port security features on switches?

1. Encrypting data payloads across insecure wireless local links.
2. Translating private IP addresses into public routable addresses.
3. Automatically assigning dynamic IP leases to client workstations.
4. Limiting switch port access based on registered MAC addresses.

Correct Answer: 4

Explanation:

Switch port security is a robust Layer 2 security feature designed to restrict unauthorized endpoint access to enterprise network infrastructure by limiting the number and identity of valid MAC addresses permitted to connect to a specific switch port. Administrators can configure static, dynamic, or sticky MAC address learning parameters. If an unauthorized device attempts to connect using an unregistered hardware address, the port security mechanism can trigger violation actions such as shutting down the interface entirely, sending SNMP trap alerts, or dropping incoming frames, protecting against unauthorized access and rogue device threats.

Question 100

Which networking device segments both collision domains and broadcast domains?

1. Network Hub
2. Enterprise Router
3. Layer 2 Switch
4. Passive Patch Panel

Correct Answer: 2

Explanation:

An enterprise router operates at Layer 3 of the OSI model and is uniquely designed to segment both collision domains and broadcast domains across network boundaries. While traditional Layer 2 switches isolate collision domains per port, they forward broadcast and multicast frames across all ports within the same VLAN. Routers, however, drop broadcast frames entirely by design, preventing broadcast storms from propagating between different subnets. This dual segmentation capability makes routers essential boundary devices for organizing large enterprise networks into secure, manageable broadcast domains.