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Question 361. Which Cisco IOS command displays the IPv4 routing table on a router?

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

Correct Answer: 3. show ip route

Explanation :-

The show ip route command displays the IPv4 routing table maintained by a Cisco router or Layer 3 device. The routing table contains routes learned through connected interfaces, static configuration, and dynamic routing protocols. It also provides information about route sources, administrative distance, metrics, next-hop addresses, and outgoing interfaces. show interfaces provides interface statistics and status, show arp displays IPv4-to-MAC mappings, and show vlan brief summarizes VLAN information on a switch. Therefore, show ip route is the appropriate command for examining IPv4 routes and determining how the device will forward packets toward a destination network.

Question 362. Which IPv4 address is a valid host address in the 192.168.10.0/24 network?

1. 192.168.10.25
2. 192.168.11.25
3. 192.168.10.0
4. 192.168.10.255

Correct Answer: 1. 192.168.10.25

Explanation :-

In the 192.168.10.0/24 network, the subnet mask is 255.255.255.0. The network address is 192.168.10.0, and the broadcast address is 192.168.10.255. The usable host range is therefore 192.168.10.1 through 192.168.10.254. The address 192.168.10.25 falls within that usable range and is a valid host address. 192.168.11.25 belongs to a different /24 network, while the network and broadcast addresses are not normally assigned to individual hosts. Therefore, 192.168.10.25 is the valid host address among the choices.

Question 363. Which protocol is responsible for translating domain names such as example.com into IP addresses?

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

Correct Answer: 4. DNS

Explanation :-

The Domain Name System (DNS) translates human-readable domain names into IP addresses that network devices can use for communication. For example, a DNS lookup can resolve a hostname such as example.com to an IPv4 or IPv6 address. This allows users and applications to use memorable names instead of numerical addresses. DHCP is primarily used to provide hosts with network configuration information, SNMP supports network management, and NTP synchronizes device clocks. DNS uses a distributed hierarchical database and can provide different record types for various services and address families. Therefore, DNS is the protocol responsible for domain-name resolution.

Question 364. What is the primary function of a router in an IP network?

1. Learn Ethernet MAC addresses only
2. Forward packets between different IP networks
3. Provide physical Ethernet connectivity only
4. Convert hostnames into IP addresses

Correct Answer: 2. Forward packets between different IP networks

Explanation :-

A router connects different Layer 3 networks and forwards IP packets toward their destinations based on information in its routing table. When a packet arrives, the router examines the destination IP address, determines the best matching route, and forwards the packet through the appropriate interface or next hop. Switches primarily forward Ethernet frames within Layer 2 networks, while DNS performs name resolution. Although routers can provide additional services such as DHCP relay, NAT, and access control, their fundamental role is Layer 3 packet forwarding between networks. Therefore, forwarding packets between different IP networks is the primary function of a router.

Question 365. Which subnet mask corresponds to an IPv4 /28 prefix?

1. 255.255.255.240
2. 255.255.255.224
3. 255.255.255.192
4. 255.255.255.248

Correct Answer: 1. 255.255.255.240

Explanation :-

A /28 IPv4 prefix contains 28 network bits and 4 host bits. The first three octets are fully dedicated to the network, represented as 255.255.255, while four network bits in the final octet produce the value 240. Therefore, the correct subnet mask is 255.255.255.240. A /28 subnet contains 16 total IPv4 addresses, with 14 normally usable host addresses in a traditional subnet. A /27 uses 255.255.255.224, a /26 uses 255.255.255.192, and a /29 uses 255.255.255.248.

Question 366. Which Cisco IOS command can be used to verify the software version and hardware information of a device?

1. show vlan brief
2. show arp
3. show version
4. show mac address-table

Correct Answer: 3. show version

Explanation :-

The show version command provides important information about a Cisco device, including the IOS or IOS XE software version, device uptime, hardware platform, memory information, interfaces, and other system details. It is commonly used during troubleshooting, inventory checks, and software verification. show vlan brief summarizes VLAN configuration, show arp displays IPv4-to-MAC address mappings, and show mac address-table displays Layer 2 forwarding information. Because show version combines software and hardware details in a single output, it is the appropriate command for verifying the operating software and basic hardware information of a Cisco device.

Question 367. Which IPv4 address represents the loopback address commonly used to test the local TCP/IP stack?

1. 169.254.1.1
2. 10.0.0.1
3. 127.0.0.1
4. 192.168.1.1

Correct Answer: 4. 127.0.0.1

Explanation :-

The IPv4 address 127.0.0.1 is the commonly used loopback address for testing the local TCP/IP stack. Addresses in the 127.0.0.0/8 range are reserved for loopback functions, and 127.0.0.1 is the most familiar representation. Traffic sent to the loopback address remains within the local host rather than being transmitted through a physical network interface. This makes it useful for determining whether the local IP stack is functioning. The 169.254.0.0/16 range is associated with link-local addressing, while 10.0.0.0/8 and 192.168.0.0/16 are private address ranges.

Question 368. Which switching method begins forwarding a frame before the entire frame has been received?

1. Store-and-forward
2. Cut-through
3. Fragment-free routing
4. Process switching

Correct Answer: 2. Cut-through

Explanation :-

Cut-through switching begins forwarding a frame after reading enough of the frame to determine its destination, rather than waiting for the complete frame to arrive. This can reduce forwarding latency because transmission begins earlier. Store-and-forward switching, by contrast, receives the entire frame before forwarding it and can therefore perform a complete frame check before transmission. Process switching is a Layer 3 packet-forwarding method rather than an Ethernet switching method. The choice of switching method involves a trade-off between latency and error checking. Therefore, cut-through switching is the method that can begin forwarding before the complete frame has been received.

Question 369. Which Cisco protocol allows a device to discover information about directly connected Cisco neighbors?

1. CDP
2. DNS
3. DHCP
4. FTP

Correct Answer: 3. CDP

Explanation :-

Cisco Discovery Protocol (CDP) allows Cisco devices to discover information about directly connected Cisco neighbors. CDP can provide details such as the neighboring device identifier, platform, capabilities, local interface, and remote port. This information can be especially useful for documenting network topology and troubleshooting physical connections. CDP is generally enabled by default on many Cisco platforms, although configuration and security requirements may vary. DNS provides name resolution, DHCP provides network configuration, and FTP transfers files. Therefore, CDP is the Cisco protocol specifically designed for discovering information about directly connected Cisco devices.

Question 370. Which command displays the VLANs configured on a Cisco switch along with their associated access ports?

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

Correct Answer: 3. show vlan brief

Explanation :-

The show vlan brief command provides a concise summary of VLANs configured on a Cisco switch. Its output commonly includes the VLAN ID, VLAN name, VLAN status, and access ports assigned to each VLAN. This makes it useful for quickly verifying VLAN creation and access-port membership. show ip route displays routing information, show interfaces provides interface-level details, and show cdp neighbors displays information about directly connected Cisco devices. When troubleshooting VLAN assignment or checking whether an access port belongs to the expected VLAN, show vlan brief is an appropriate command to use.

Question 371. Which IPv6 address type is used to identify a group of interfaces and deliver packets to all members of that group?

1. Anycast
2. Link-local
3. Global unicast
4. Multicast

Correct Answer: 4. Multicast

Explanation :-

An IPv6 multicast address identifies a group of interfaces, and packets sent to that address are delivered to the members of the multicast group. IPv6 multicast uses the FF00::/8 prefix and supports many network functions, including Neighbor Discovery and routing protocols. Anycast addresses identify multiple interfaces but deliver traffic to the nearest appropriate interface according to routing. Link-local addresses are used for communication on the local link, while global unicast addresses identify globally routable interfaces. Therefore, multicast is the IPv6 address type designed for one-to-many communication with a defined group of receiving interfaces.

Question 372. Which protocol provides automatic IP address assignment to network clients?

1. DHCP
2. SSH
3. OSPF
4. CDP

Correct Answer: 1. DHCP

Explanation :-

Dynamic Host Configuration Protocol (DHCP) provides automatic network configuration to clients. A DHCP server can assign an IPv4 address along with a subnet mask, default gateway, DNS server information, and lease parameters. This simplifies administration because network administrators do not need to manually configure every client. SSH is used for secure remote access, OSPF is a dynamic routing protocol, and CDP discovers directly connected Cisco devices. DHCP commonly operates through a lease-based process in which clients request and renew their configuration. Therefore, DHCP is the protocol responsible for automatically assigning IP addressing information to network clients.

Question 373. Which routing protocol is classified as a link-state protocol?

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

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 construct a topology database representing the network. They then use the Shortest Path First algorithm to calculate routes. This differs from RIP, which is a distance-vector routing protocol that uses hop count as its primary metric. ARP is an address-resolution protocol, and DHCP provides host configuration. OSPF supports hierarchical network design through areas and can provide rapid convergence in appropriately designed networks. Therefore, OSPF is the link-state routing protocol among the listed choices.

Question 374. Which command displays the IPv6 routing table on a Cisco router?

1. show ip route
2. show ipv6 interface
3. show ipv6 route
4. show arp

Correct Answer: 3. show ipv6 route

Explanation :-

The show ipv6 route command displays the IPv6 routing table on a Cisco router or Layer 3 device. It can show connected, local, static, and dynamically learned IPv6 routes along with information about route sources and next hops. show ip route displays the IPv4 routing table, while show ipv6 interface provides IPv6 configuration and operational information for interfaces. Traditional ARP is associated with IPv4 address resolution; IPv6 uses Neighbor Discovery instead. Therefore, show ipv6 route is the correct command for examining the routes available for forwarding IPv6 packets.

Question 375. What happens when a Layer 2 switch receives a frame destined for an unknown unicast MAC address within a VLAN?

1. The switch drops the frame immediately
2. The switch routes the frame to another VLAN
3. The switch floods the frame out applicable ports except the incoming port
4. The switch sends the frame only to the default gateway

Correct Answer: 3. The switch floods the frame out applicable ports except the incoming port

Explanation :-

When a switch receives an Ethernet frame with an unknown unicast destination MAC address, it normally floods the frame within the associated VLAN. The switch sends the frame out applicable ports except the port on which the frame was received. This behavior allows the destination device an opportunity to receive the frame while the switch learns the destination MAC address from subsequent traffic. The switch does not automatically route the frame to another VLAN or send it only to the default gateway. Once the destination MAC address is learned, future frames can normally be forwarded directly through the associated switch port.

Question 376. Which technology allows multiple physical switch links to operate as one logical link?

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

Correct Answer: 1. EtherChannel

Explanation :-

EtherChannel combines multiple physical Ethernet links into a single logical link. This can provide increased aggregate bandwidth and redundancy between switches or other compatible devices. From the perspective of protocols such as STP, the bundled interfaces can be treated as one logical connection, which helps avoid treating each individual member link as a separate Layer 2 path. EtherChannel can be negotiated using technologies such as LACP or PAgP, depending on platform and configuration. NAT translates IP addresses, port security controls MAC addresses on switch ports, and DHCP snooping helps protect against unauthorized DHCP servers. Therefore, EtherChannel is the correct technology.

Question 377. Which command can be used to view the saved startup configuration on a Cisco device?

1. show running-config
2. show startup-config
3. show version
4. show flash

Correct Answer: 2. show startup-config

Explanation :-

The show startup-config command displays the configuration saved in NVRAM and normally used when the device boots. It is useful for comparing the saved configuration with the active running configuration. The show running-config command displays the configuration currently active in RAM, which may include changes that have not yet been saved. show version provides system and software information, while show flash displays information about files stored in flash memory. Administrators should understand the distinction between running and startup configurations because unsaved configuration changes can be lost after a reload. Therefore, show startup-config is the appropriate command for viewing the saved configuration.

Question 378. Which security feature helps protect a switch against unauthorized DHCP servers?

1. PortFast
2. EtherChannel
3. DHCP snooping
4. CDP

Correct Answer: 3. DHCP snooping

Explanation :-

DHCP snooping is a Layer 2 security feature that helps protect a switched network from unauthorized or rogue DHCP servers. The switch classifies interfaces as trusted or untrusted and can allow DHCP server responses only through trusted interfaces. DHCP snooping can also build a binding database containing information such as client MAC addresses, assigned IP addresses, VLANs, and switch ports. PortFast is used to accelerate spanning-tree transition on appropriate edge ports, EtherChannel bundles physical links, and CDP discovers Cisco neighbors. Therefore, DHCP snooping is the feature specifically associated with controlling and validating DHCP traffic on a switch.

Question 379. Which IPv4 address range is reserved for link-local addressing when a host cannot obtain an address through DHCP?

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

Correct Answer: 4. 169.254.0.0/16

Explanation :-

The IPv4 169.254.0.0/16 range is reserved for link-local addressing, commonly associated with Automatic Private IP Addressing (APIPA) on hosts that cannot obtain an IPv4 address through DHCP. An address from this range allows limited communication with other devices on the same local link that use compatible link-local addressing, but it is not intended for normal routed communication across an enterprise network or the public Internet. The 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 ranges are RFC 1918 private address spaces. Therefore, 169.254.0.0/16 is the correct link-local range.

Question 380. Which command is commonly used to test IP connectivity to a remote destination from a Cisco device?

1. ping
2. traceroute
3. show version
4. show vlan brief

Correct Answer: 1. ping

Explanation :-

The ping command is commonly used to test basic IP connectivity between a Cisco device and a destination. In IPv4, traditional ping testing uses ICMP Echo Request and Echo Reply messages. A successful response indicates that the destination was reachable at the IP layer and responded to the request, although it does not guarantee that every application service on the destination is functioning. traceroute is used to examine the Layer 3 path toward a destination, while show version and show vlan brief provide device or VLAN information. Therefore, ping is the standard command for basic IP reachability testing.