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Question 361

What command displays the active IP routing table?

1. show ip interface brief
2. show ip route
3. show running-config
4. show version

Correct Answer: 2

Explanation:

The show ip route command is an essential diagnostic utility executed in privileged EXEC mode on Cisco routers. When invoked, it displays the complete active Layer 3 routing table, detailing all connected, static, and dynamically learned routes. The output lists destination subnet prefixes, administrative distances, metric values, next-hop IP addresses, and exit physical interfaces. Network administrators rely heavily on this command to verify route propagation, confirm routing protocols are populating paths correctly, and troubleshoot packet delivery failures across enterprise networks.

Question 362

Which protocol translates private IP addresses to public ones?

1. Address Resolution Protocol
2. Dynamic Host Configuration Protocol
3. Network Address Translation
4. Internet Control Message Protocol

Correct Answer: 3

Explanation:

Network Address Translation is a core networking technology used to map internal private IP addresses to external public IP addresses, conserving scarce IPv4 address space. NAT operates on border routers or firewalls, translating source or destination IP headers as packets cross between internal local networks and the public internet. This process ensures that internal hosts remain hidden from direct external inspection while retaining full outbound connectivity. Variants like Port Address Translation allow thousands of internal devices to share a single public IP address using unique port identifiers.

Question 363

What layer of the OSI model does a router operate?

1. Layer 1
2. Layer 2
3. Layer 3
4. Layer 4

Correct Answer: 3

Explanation:

Routers operate at Layer 3, the Network layer of the OSI reference model. Unlike Layer 2 switches that forward frames based on physical MAC addresses, routers examine logical network layer addresses, such as IPv4 or IPv6 headers, to make intelligent path selection decisions. By analyzing destination IP addresses and consulting routing tables, routers determine the optimal path across interconnected networks, segment broadcast domains, and facilitate communication between disparate subnets and wide area network links.

Question 364

Which IEEE standard defines virtual local area network trunking?

1. IEEE 802.3
2. IEEE 802.1Q
3. IEEE 802.1w
4. IEEE 802.11

Correct Answer: 2

Explanation:

The IEEE 802.1Q standard defines the protocol for Virtual Local Area Network bridging and trunking across Ethernet networks. It introduces a four-byte tag inserted directly into the Ethernet frame header, containing a 12-bit VLAN identifier that allows a single physical switch port to carry traffic for multiple distinct VLANs simultaneously. This tagging mechanism enables enterprise networks to scale efficiently, segment traffic logically, and isolate broadcast domains without requiring dedicated physical cabling for every separate logical network segment.

Question 365

What is the default administrative distance of a static route?

1. 0
2. 1
3. 90
4. 110

Correct Answer: 2

Explanation:

Administrative distance represents the trustworthiness and preference level assigned to different routing information sources on Cisco routers, where lower numerical values indicate higher reliability. In Cisco IOS routing architecture, static routes configured manually by network administrators are assigned a default administrative distance of 1. This makes static routes extremely trustworthy, preferred over almost all dynamic routing protocols such as EIGRP at 90 and OSPF at 110, ensuring that manually defined paths override dynamic updates during path selection.

Question 366

Which protocol dynamically assigns IP addresses to client devices?

1. DNS
2. DHCP
3. SNMP
4. NTP

Correct Answer: 2

Explanation:

Dynamic Host Configuration Protocol is a network management protocol used to automate the assignment of IP addresses, subnet masks, default gateways, and DNS server configurations to client devices on an IP network. DHCP eliminates the administrative overhead and potential configuration errors associated with manual static addressing. Operating over UDP ports 67 and 68, the protocol utilizes a four-step discover, offer, request, and acknowledgment exchange to lease configuration parameters dynamically when devices join the network segment.

Question 367

What multicast address does OSPF use for all routers?

1. 224.0.0.5
2. 224.0.0.6
3. 224.0.0.9
4. 224.0.0.10

Correct Answer: 1

Explanation:

The Open Shortest Path First routing protocol utilizes specific reserved multicast addresses to exchange routing telemetry efficiently among neighboring devices. The address 224.0.0.5 is designated for all OSPF routers on a network segment, used for sending hello packets and general link-state updates. Conversely, the address 224.0.0.6 is reserved specifically for designated routers and backup designated routers on multi-access broadcast segments, ensuring that designated routers receive specialized routing update packets efficiently without disturbing non-designated nodes.

Question 368

Which cable type connects two switches without crossover cables?

1. Straight-through cable
2. Rollover cable
3. Serial cable
4. Console cable

Correct Answer: 1

Explanation:

Modern Ethernet switches feature automatic medium-dependent interface crossover technology, which automatically detects the polarity of connected cables and reconfigures transmit and receive pairs internally. Historically, connecting two similar networking devices required a physical crossover cable. However, with Auto-MDIX enabled by default on modern Cisco Catalyst switch ports, technicians can utilize standard straight-through twisted-pair copper cables to interconnect switches, hubs, and workstations seamlessly without worrying about pinout mismatches or signal reversal issues.

Question 369

What flag initiates a TCP session during the handshake?

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

Correct Answer: 4

Explanation:

The Synchronize flag is an essential control flag utilized within the Transmission Control Protocol header to initiate connection establishment during the standard three-way handshake. When a client wants to open a reliable session with a server, it transmits a segment with the SYN flag set and an initial sequence number. The server responds with a SYN-ACK segment, and the client finishes the handshake with an ACK. This sequence synchronizes sequence numbers and establishes reliable, connection-oriented data transmission parameters.

Question 370

Which port does secure shell remote administration utilize?

1. Port 21
2. Port 22
3. Port 23
4. Port 80

Correct Answer: 2

Explanation:

Secure Shell operates by default over Transmission Control Protocol port 22. SSH is a cryptographic network protocol designed to provide secure, encrypted command-line administration and remote login capabilities across unsecured IP networks. It serves as a secure replacement for legacy unencrypted protocols like Telnet, wrapping all keystrokes, passwords, and management commands in robust encryption wrappers to protect network infrastructure against packet sniffing, credential theft, and man-in-the-middle attacks.

Question 371

What metric does RIP use to determine best paths?

1. Bandwidth
2. Delay
3. Hop count
4. Cost

Correct Answer: 3

Explanation:

The Routing Information Protocol is a legacy distance-vector routing protocol that utilizes hop count as its sole metric to determine the best path to a destination network. Each router traversed along a path counts as a single hop, adding one to the metric value. RIP enforces a strict maximum hop count limit of 15; any destination network requiring 16 hops or more is considered unreachable and assigned an infinite metric. While simple to configure, hop-count-only metrics make RIP unsuitable for modern complex networks.

Question 372

Which tool tests end-to-end network connectivity using ICMP echoes?

1. Telnet
2. Ping
3. Traceroute
4. NetFlow

Correct Answer: 2

Explanation:

Ping is a fundamental network diagnostic utility that utilizes Internet Control Message Protocol echo request and echo reply messages to test basic end-to-end IP connectivity between source and destination hosts. When executed, ping measures round-trip transmission time, packet loss percentages, and protocol responsiveness. Network administrators rely on ping as the first line of troubleshooting to verify whether remote IP hosts are reachable, validate DNS name resolutions, and confirm basic network interface card functionality across local and wide area networks.

Question 373

What is the broadcast address for subnet 192.168.1.0/24?

1. 192.168.1.0
2. 192.168.1.254
3. 192.168.1.255
4. 192.168.2.0

Correct Answer: 3

Explanation:

In IPv4 networking, every subnet includes a reserved broadcast address at the absolute highest end of its address range. For a standard Class C subnet with a /24 prefix (subnet mask 255.255.255.0), the network range spans from 192.168.1.0 to 192.168.1.255. The lowest address (192.168.1.0) is permanently reserved as the network identifier, while the highest address (192.168.1.255) functions as the directed broadcast address, used to transmit data packets to all devices residing within that specific subnet simultaneously.

Question 374

Which device operates exclusively at Layer 2 of OSI?

1. Router
2. Firewall
3. Hub
4. Layer 2 Switch

Correct Answer: 4

Explanation:

A Layer 2 switch operates primarily at the Data Link layer of the OSI reference model. It examines the source and destination MAC addresses contained within incoming Ethernet frames to forward traffic selectively across appropriate physical ports. Unlike hubs that broadcast electrical signals blindly across all ports, Layer 2 switches build content-addressable memory tables to map MAC addresses to specific ports, reducing unnecessary network traffic collision domains and improving overall segment efficiency.

Question 375

What protocol secures web traffic utilizing cryptographic certificates?

1. HTTP
2. FTP
3. HTTPS
4. TFTP

Correct Answer: 3

Explanation:

Hypertext Transfer Protocol Secure is the secure extension of standard HTTP, designed to protect web communications between client browsers and web servers against eavesdropping, tampering, and man-in-the-middle attacks. HTTPS wraps standard HTTP data payloads inside Transport Layer Security cryptographic encryption wrappers backed by digital certificates issued by trusted certificate authorities. Network administrators configure HTTPS over TCP port 443 to ensure robust data confidentiality, integrity, and authentication for modern web applications.

Question 376

Which IPv6 address type replaces traditional broadcast communications?

1. Global Unicast
2. Link-Local
3. Multicast
4. Anycast

Correct Answer: 3

Explanation:

IPv6 architecture completely eliminates traditional broadcast traffic mechanics used in IPv4, replacing them with advanced multicast and anycast addressing schemes. In IPv6, packets destined for multiple nodes are transmitted to specialized multicast groups, such as solicited-node multicast addresses. This targeted transmission ensures that only interested nodes process the packets, significantly reducing unnecessary network processing overhead and conserving bandwidth across local segments compared to legacy broadcast storms.

Question 377

What command saves running configuration into persistent NVRAM storage?

1. copy running-config startup-config
2. write erase
3. reload
4. show running-config

Correct Answer: 1

Explanation:

The copy running-config startup-config command executed in privileged EXEC mode on Cisco devices saves the active configuration file from volatile random-access memory into non-volatile random-access memory. Because running configurations are erased whenever a device reboots or loses electrical power, saving configurations to startup memory ensures that all administrative modifications persist across reboots. Technicians must execute this command after making any operational changes to guarantee network stability during maintenance windows.

Question 378

Which protocol synchronizes network device clocks across IP networks?

1. Syslog
2. NTP
3. SNMP
4. DHCP

Correct Answer: 2

Explanation:

Network Time Protocol is a standard networking protocol designed to synchronize the clocks of computer systems and network infrastructure devices across packet-switched IP networks. NTP utilizes a hierarchical stratum architecture to distribute accurate timekeeping data from authoritative reference sources, such as atomic clocks or GPS receivers. Precise time synchronization is critical for enterprise network operations, enabling accurate log correlation, security auditing, certificate validation, and precise fault isolation during troubleshooting procedures.

Question 379

What is the default OSPF hello packet interval timer?

1. 5 seconds
2. 10 seconds
3. 30 seconds
4. 40 seconds

Correct Answer: 2

Explanation:

The Open Shortest Path First routing protocol utilizes Hello packets to discover neighboring routers, establish bidirectional communication, and maintain dynamic adjacencies within an OSPF area. On multi-access broadcast networks and point-to-point serial links, the default OSPF hello interval timer is set to 10 seconds, with a corresponding dead interval timer of 40 seconds. If a router fails to receive an incoming Hello packet before the dead timer expires, it tears down the adjacency and recalculates the topology.

Question 380

Which command verifies switch port trunking operational status?

1. show ip interface brief
2. show interfaces trunk
3. show cdp neighbors
4. show ip route

Correct Answer: 2

Explanation:

The show interfaces trunk command is an essential diagnostic utility executed in privileged EXEC mode within the Cisco IOS command-line interface. When invoked, it displays all physical and logical switch ports currently operating as 802.1Q trunk links. The output details critical configuration parameters including encapsulation types in use, native VLAN assignments, operational trunk status, allowed VLANs on the trunk, and VLANs currently active in the spanning tree forwarding state.