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Question 261. Which protocol resolves an IPv4 address to the corresponding MAC address on a local Ethernet network?

1. DNS
2. ARP
3. DHCP
4. ICMP

Correct Answer: 2. ARP

Explanation :-

Address Resolution Protocol (ARP) maps an IPv4 address to a MAC address on a local Ethernet network. When a host needs to send an IPv4 packet to another device on the same local network, it uses ARP to discover the destination device’s MAC address. The resulting IP-to-MAC mapping can be stored temporarily in the ARP cache. DNS resolves hostnames to IP addresses, DHCP provides network configuration, and ICMP supports control and diagnostic messaging. ARP is therefore essential for IPv4 communication across Ethernet when the destination MAC address is not already known.

Question 262. Which command displays the IPv4 routing table on a Cisco router?

1. show arp
2. show interfaces
3. show ip interface brief
4. show ip route

Correct Answer: 4. show ip route

Explanation :-

The show ip route command displays the IPv4 routing table on a Cisco router. The output identifies connected, static, and dynamically learned routes along with routing sources, network prefixes, administrative distances, metrics, and next-hop information. This command is frequently used to determine how a router will forward packets toward a particular destination. show arp displays IP-to-MAC mappings, show interfaces provides interface details, and show ip interface brief gives a concise interface status summary. Therefore, show ip route is the appropriate command for examining the IPv4 routing table.

Question 263. Which device separates broadcast domains by default?

1. Router
2. Hub
3. Repeater
4. Layer 2 bridge

Correct Answer: 1. Router

Explanation :-

A router separates broadcast domains because routers do not normally forward Layer 2 broadcast frames between interfaces. Each routed interface represents a different Layer 3 network and therefore a separate broadcast domain. Switches can create multiple broadcast domains when VLANs are configured, but a traditional Layer 2 switch without VLAN segmentation operates within a single broadcast domain. Hubs and repeaters do not separate broadcast domains. Routers also make Layer 3 forwarding decisions based on destination IP addresses. Therefore, a router is the device that separates broadcast domains by default.

Question 264. Which Cisco IOS command displays information about directly connected Cisco neighbors discovered through CDP?

1. show ip route
2. show vlan brief
3. show cdp neighbors
4. show startup-config

Correct Answer: 3. show cdp neighbors

Explanation :-

The show cdp neighbors command displays information about Cisco devices directly connected to the local device and discovered through Cisco Discovery Protocol. Typical information includes the neighboring device ID, local interface, neighbor’s port ID, platform, and device capabilities. This makes the command useful for network topology discovery and troubleshooting physical connections. show ip route displays routing information, show vlan brief displays VLAN information, and show startup-config displays the saved configuration. Therefore, show cdp neighbors is the correct command for viewing directly connected Cisco neighbors.

Question 265. Which transport-layer protocol provides reliable, connection-oriented delivery?

1. UDP
2. ARP
3. ICMP
4. TCP

Correct Answer: 4. TCP

Explanation :-

Transmission Control Protocol (TCP) provides reliable, connection-oriented transport between applications. TCP establishes a connection before transferring data and uses sequence numbers, acknowledgments, retransmissions, and flow control to provide reliable delivery. UDP is connectionless and does not provide the same built-in reliability mechanisms. ARP operates at the boundary of Layer 2 and Layer 3 for IPv4 address resolution, while ICMP is used for network control and diagnostic messages. Applications such as HTTP-based services, SSH, and FTP commonly use TCP. Therefore, TCP is the transport-layer protocol that provides reliable, connection-oriented delivery.

Question 266. Which command can be used to verify the VLANs configured on a Cisco switch and their assigned access ports?

1. show vlan brief
2. show ip route
3. show arp
4. show version

Correct Answer: 1. show vlan brief

Explanation :-

The show vlan brief command provides a concise display of VLAN information on a Cisco switch. It normally shows the VLAN ID, VLAN name, status, and ports assigned to each VLAN. This makes it useful for quickly verifying whether VLANs exist and whether access ports have been assigned to the expected VLAN. show ip route displays routing information, show arp displays IP-to-MAC mappings, and show version displays software and hardware information. Therefore, show vlan brief is the appropriate command for checking VLAN membership and status.

Question 267. What is the primary purpose of NAT in an IPv4 network?

1. Preventing Layer 2 loops
2. Assigning VLAN IDs
3. Translating addresses between different IP address spaces
4. Synchronizing device clocks

Correct Answer: 3. Translating addresses between different IP address spaces

Explanation :-

Network Address Translation (NAT) translates IP addresses between different address spaces. A common use is translating private IPv4 addresses used inside an organization into public IPv4 addresses for Internet communication. NAT can conserve public IPv4 address space and allow multiple internal hosts to share one or more public addresses, depending on the configuration. VLAN assignment is a switching function, STP prevents Layer 2 loops, and NTP synchronizes clocks. NAT operates as part of the packet-forwarding process on devices configured to perform translation. Therefore, translating addresses between different IP address spaces is the primary purpose of NAT.

Question 268. Which IPv4 prefix identifies link-local addresses used when a host cannot obtain an address through normal configuration methods?

1. 10.0.0.0/8
2. 169.254.0.0/16
3. 172.16.0.0/12
4. 192.168.0.0/16

Correct Answer: 2. 169.254.0.0/16

Explanation :-

The IPv4 range 169.254.0.0/16 is reserved for link-local addressing. Hosts may automatically assign an address from this range when they are configured to obtain an address dynamically but cannot obtain one through a DHCP server. Link-local addresses allow limited communication on the local network but are not intended for normal routed communication across networks. The ranges 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 are private IPv4 address ranges. Therefore, 169.254.0.0/16 is the correct prefix for IPv4 link-local addressing.

Question 269. Which command displays the saved startup configuration on a Cisco device?

1. show running-config
2. show interfaces
3. show startup-config
4. show flash:

Correct Answer: 3. show startup-config

Explanation :-

The show startup-config command displays the configuration saved in NVRAM and intended to be loaded when the Cisco device starts. It is useful for verifying whether configuration changes have been saved after modifying the running configuration. The show running-config command displays the currently active configuration stored in RAM. show interfaces provides interface information, while show flash: displays files stored in flash memory. If the running configuration has changed but has not been copied to the startup configuration, the two configurations may differ. Therefore, show startup-config is the correct command.

Question 270. Which protocol is used to automatically discover the IP address of a DHCP server and obtain network configuration from it?

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

Correct Answer: 1. DHCP

Explanation :-

Dynamic Host Configuration Protocol (DHCP) enables clients to automatically obtain IP configuration from a DHCP server. A typical DHCP exchange involves the client discovering available DHCP servers, receiving an offer, requesting configuration, and receiving an acknowledgment. DHCP can provide an IPv4 address, subnet mask, default gateway, DNS server information, and lease duration. SNMP is used for network management, NTP synchronizes clocks, and FTP transfers files. DHCP is especially useful in networks with many hosts because it reduces manual configuration and helps manage address allocation centrally. Therefore, DHCP is the correct protocol.

Question 271. Which command displays detailed operational statistics for interfaces on a Cisco device?

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

Correct Answer: 1. show interfaces

Explanation :-

The show interfaces command displays detailed information about interfaces on a Cisco device. Depending on the interface, the output can include physical and line protocol status, bandwidth, errors, packet counts, duplex settings, encapsulation, and other operational statistics. This makes the command useful for troubleshooting connectivity and identifying physical or data-link problems. show vlan brief focuses on VLAN information, show ip route displays routing information, and show cdp neighbors identifies directly connected Cisco devices. Therefore, show interfaces is the appropriate command when detailed interface statistics are required.

Question 272. Which protocol is commonly used to monitor and manage network devices?

1. TFTP
2. SNMP
3. STP
4. ARP

Correct Answer: 2. SNMP

Explanation :-

Simple Network Management Protocol (SNMP) is commonly used to monitor and manage network devices such as routers, switches, servers, and other infrastructure. Network management systems can use SNMP to retrieve information such as interface status, traffic counters, and device statistics. Depending on the SNMP version and configuration, it can also support management operations and notifications. TFTP is primarily used for simple file transfers, STP prevents Layer 2 loops, and ARP resolves IPv4 addresses to MAC addresses. Therefore, SNMP is the protocol most directly associated with network monitoring and management.

Question 273. Which type of Ethernet cable is traditionally used to connect a PC directly to a switch?

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

Correct Answer: 3. Straight-through cable

Explanation :-

A straight-through Ethernet cable was traditionally used to connect devices of different Ethernet types, such as a PC to a switch. The transmit and receive pairs remain in the same pin arrangement at both ends. A crossover cable was traditionally used between similar device types, such as switch-to-switch or PC-to-PC connections, although modern devices commonly support Auto-MDIX and can automatically accommodate cable types. Rollover cables are associated with console connections on certain Cisco equipment, while serial cables are used for specific serial interfaces. Therefore, the traditional answer for a PC-to-switch Ethernet connection is a straight-through cable.

Question 274. Which IPv6 address range is used for link-local unicast addresses?

1. 2000::/3
2. FC00::/7
3. FF00::/8
4. FE80::/10

Correct Answer: 4. FE80::/10

Explanation :-

IPv6 link-local unicast addresses use the FE80::/10 prefix. These addresses are automatically available on IPv6-enabled interfaces and are used for communication on the local link. Routers do not forward link-local traffic between different links. The 2000::/3 range is used for global unicast addresses, FC00::/7 identifies unique local addresses, and FF00::/8 identifies multicast addresses. Link-local addresses are important for IPv6 neighbor discovery and other local-link operations. Therefore, FE80::/10 is the correct IPv6 link-local address range.

Question 275. Which Cisco feature allows multiple physical Ethernet links to operate as one logical link?

1. EtherChannel
2. Port security
3. DHCP snooping
4. NAT

Correct Answer: 3. EtherChannel

Explanation :-

EtherChannel allows multiple physical Ethernet interfaces to be bundled into a single logical interface. This provides increased aggregate bandwidth and redundancy while simplifying management because the bundled links are treated as one logical connection. EtherChannel can use negotiation protocols such as LACP or PAgP, depending on the configuration. Port security controls permitted MAC addresses, DHCP snooping helps protect against unauthorized DHCP servers, and NAT translates IP addresses. EtherChannel is commonly deployed between switches and between switches and other capable network devices. Therefore, EtherChannel is the feature that combines multiple physical links into one logical connection.

Question 276. Which command displays the ARP cache on a Cisco device?

1. show mac address-table
2. show arp
3. show ip route
4. show version

Correct Answer: 2. show arp

Explanation :-

The show arp command displays the Address Resolution Protocol cache on a Cisco device. The output generally shows IPv4 addresses and their associated MAC addresses, along with interface information. This information is useful when troubleshooting local IPv4 connectivity and verifying IP-to-MAC resolution. The show mac address-table command displays Layer 2 MAC address learning on a switch, while show ip route displays the routing table and show version provides system information. Therefore, show arp is the appropriate command for viewing IPv4 ARP entries.

Question 277. Which routing protocol is classified as a link-state interior gateway protocol?

1. RIP
2. OSPF
3. FTP
4. ARP

Correct Answer: 2. OSPF

Explanation :-

Open Shortest Path First (OSPF) is a link-state interior gateway routing protocol. OSPF routers exchange link-state information and build a topology database from which they calculate shortest paths using the Shortest Path First algorithm. OSPF supports hierarchical design using areas and can provide faster and more scalable routing than traditional distance-vector protocols in many network environments. RIP is a distance-vector routing protocol, while FTP is a file-transfer protocol and ARP is used for IPv4 address resolution. Therefore, OSPF is the link-state interior gateway protocol among the listed choices.

Question 278. Which command can be used to test basic IP connectivity to a remote device?

1. ping
2. show version
3. show vlan brief
4. copy running-config startup-config

Correct Answer: 3. ping

Explanation :-

The ping command tests basic IP connectivity between the local device and a specified destination. It uses Internet Control Message Protocol (ICMP) echo request and echo reply messages to determine whether the destination responds and to provide basic information about reachability and response time. A successful ping confirms that the destination is reachable at the IP layer, although it does not guarantee that every application or service is functioning. The other commands provide device information, VLAN information, or configuration-saving functionality. Therefore, ping is the standard command for testing basic IP connectivity.

Question 279. What is the purpose of an access control list (ACL) on a Cisco router?

1. To synchronize device clocks
2. To learn MAC addresses automatically
3. To assign IP addresses dynamically
4. To permit or deny traffic according to defined criteria

Correct Answer: 4. To permit or deny traffic according to defined criteria

Explanation :-

An access control list (ACL) contains ordered permit and deny statements used to control traffic according to defined criteria. Depending on the ACL type, criteria can include source and destination IP addresses, protocols, and port numbers. ACLs can be applied to interfaces or used for other security and traffic-control functions. Cisco ACLs are processed sequentially, and an implicit deny exists at the end of the list when applicable. ACLs do not synchronize clocks, learn MAC addresses, or dynamically assign IP addresses. Therefore, controlling traffic through defined permit and deny conditions is the primary purpose of an ACL.

Question 280. Which Cisco IOS command displays the current software version, uptime, and configuration register information?

1. show arp
2. show vlan brief
3. show version
4. show ip route

Correct Answer: 3. show version

Explanation :-

The show version command provides system information including the Cisco IOS software version, device uptime, hardware platform, memory information, and configuration register value. It is a common diagnostic command used when identifying the software and hardware environment of a Cisco device. The configuration register can influence how the device boots and how certain startup behaviors are handled. show arp displays ARP entries, show vlan brief displays VLAN information, and show ip route displays the IPv4 routing table. Therefore, show version is the correct command for viewing these system details.