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Question 301. Which Cisco IOS command displays the IPv4 routing table?

1. show arp
2. show interfaces
3. show ip route
4. show version

Correct Answer: 3. show ip route

Explanation :-

The show ip route command displays the IPv4 routing table on a Cisco router or Layer 3 device. The output identifies routes learned through connected interfaces, static configuration, and dynamic routing protocols. It can also show administrative distance, metric, next-hop information, and the outgoing interface used to reach a destination. This command is commonly used to troubleshoot routing problems and verify whether a path to a particular network exists. show arp displays IPv4-to-MAC mappings, show interfaces provides interface statistics, and show version displays system information. Therefore, show ip route is the correct command.

Question 302. Which device primarily forwards Ethernet frames using destination MAC addresses?

1. Switch
2. Router
3. Firewall
4. DNS server

Correct Answer: 1. Switch

Explanation :-

A traditional Ethernet switch primarily operates at Layer 2 and forwards frames using destination MAC addresses. The switch learns source MAC addresses from incoming frames and stores them in its MAC address table. When a destination MAC address is known, the switch forwards the frame through the corresponding interface. If the destination is unknown, the switch generally floods the frame within the appropriate VLAN. Routers primarily make Layer 3 forwarding decisions using IP addresses, while DNS servers provide name-resolution services. Therefore, a switch is the network device primarily responsible for forwarding Ethernet frames based on MAC addresses.

Question 303. Which protocol provides secure encrypted remote access to the Cisco command-line interface?

1. FTP
2. TFTP
3. Telnet
4. SSH

Correct Answer: 4. SSH

Explanation :-

Secure Shell (SSH) provides encrypted remote command-line access to Cisco network devices. SSH protects authentication credentials and session information by encrypting the communication between the administrator and the device. Telnet also provides remote CLI access but sends its traffic without encryption, making it less suitable for secure administration. FTP and TFTP are primarily file-transfer protocols rather than remote CLI access protocols. Cisco devices can be configured with SSH for secure management through the VTY lines. Therefore, SSH is the protocol used for encrypted remote CLI access.

Question 304. Which IPv4 address is within the RFC 1918 private address space?

1. 172.32.5.10
2. 192.168.25.10
3. 8.8.8.8
4. 172.40.10.1

Correct Answer: 2. 192.168.25.10

Explanation :-

RFC 1918 defines three private IPv4 address ranges: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. The address 192.168.25.10 falls within the 192.168.0.0/16 private range and can therefore be used inside private networks. Addresses in the private ranges are not directly routable across the public Internet and are commonly used with NAT when Internet connectivity is required. The addresses 172.32.5.10 and 172.40.10.1 are outside the private 172.16.0.0/12 range, while 8.8.8.8 is a public IPv4 address. Therefore, 192.168.25.10 is correct.

Question 305. What is the main purpose of a subnet mask in IPv4 networking?

1. To identify the network and host portions of an IPv4 address
2. To identify a device’s MAC address
3. To assign a DNS server
4. To encrypt IP packets

Correct Answer: 1. To identify the network and host portions of an IPv4 address

Explanation :-

An IPv4 subnet mask identifies which bits of an IPv4 address represent the network portion and which bits represent the host portion. This information allows devices to determine whether a destination is on the local subnet or on a remote network. For example, the mask 255.255.255.0 corresponds to a /24 prefix, leaving eight bits for host addressing. A subnet mask does not identify a device’s MAC address, assign DNS information, or encrypt packets. Proper subnetting allows networks to be divided into smaller logical networks and helps devices make local-versus-remote forwarding decisions.

Question 306. Which protocol dynamically provides IPv4 addresses and other network parameters to clients?

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

Correct Answer: 3. DHCP

Explanation :-

Dynamic Host Configuration Protocol (DHCP) automatically provides clients with IPv4 configuration information. A DHCP server can supply an IP address, subnet mask, default gateway, DNS server addresses, and lease information. This reduces the need for administrators to manually configure each host and helps manage address allocation centrally. DNS is responsible for name resolution, NTP synchronizes clocks, and SNMP is used for network monitoring and management. DHCP commonly uses UDP ports 67 and 68 for server and client communication. Therefore, DHCP is the protocol designed to dynamically provide IPv4 addresses and related network parameters.

Question 307. Which Cisco command displays the configuration currently active in RAM?

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

Correct Answer: 3. show running-config

Explanation :-

The show running-config command displays the configuration currently active on a Cisco device. The running configuration is stored in RAM and contains the settings presently being used by the device. Changes made to this configuration generally take effect immediately but are not automatically retained after a reload. To preserve changes, an administrator can copy the running configuration to the startup configuration stored in NVRAM. show startup-config displays the saved configuration, while show flash: displays files in flash memory. Therefore, show running-config is the correct command for viewing the active configuration.

Question 308. Which IPv6 address range is used for global unicast addresses?

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

Correct Answer: 4. 2000::/3

Explanation :-

The IPv6 2000::/3 range is allocated for global unicast addresses. Global unicast addresses are intended for routable IPv6 communication across interconnected networks and are comparable in general purpose to public IPv4 addresses. The FE80::/10 range is reserved for link-local unicast addresses, FC00::/7 is used for unique local addresses, and FF00::/8 identifies multicast addresses. IPv6 uses a much larger address space than IPv4 and supports multiple address types for different communication requirements. Therefore, 2000::/3 is the correct global unicast range.

Question 309. What does a switch normally do when it receives a frame with an unknown destination MAC address?

1. Drops the frame
2. Sends it only to the default gateway
3. Floods it out other ports in the same VLAN
4. Converts it to an IP packet

Correct Answer: 3. Floods it out other ports in the same VLAN

Explanation :-

When a switch receives an Ethernet frame whose destination MAC address is not present in its MAC address table, the frame is treated as an unknown unicast. The switch normally floods the frame out other forwarding interfaces in the same VLAN, excluding the interface where the frame was received. This allows the intended destination to receive the frame while the switch learns MAC addresses from subsequent traffic. The switch does not normally discard an unknown unicast immediately, send it only to the default gateway, or convert it into an IP packet. Therefore, flooding within the VLAN is the correct behavior.

Question 310. Which command displays a concise summary of VLANs and their assigned access ports?

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

Correct Answer: 2. show vlan brief

Explanation :-

The show vlan brief command displays a concise summary of VLANs configured on a Cisco switch. The output normally includes the VLAN ID, VLAN name, status, and access ports assigned to each VLAN. It is useful for verifying VLAN creation and checking whether switch access ports have been placed into the expected VLAN. show ip route displays routing information, show arp displays IPv4-to-MAC mappings, and show version provides system and software information. Therefore, show vlan brief is the appropriate command for quickly reviewing VLANs and access-port assignments.

Question 311. Which protocol is used by IPv6 hosts to discover neighboring devices and routers on the local link?

1. NDP
2. DHCPv4
3. FTP
4. SNMP

Correct Answer: 1. NDP

Explanation :-

IPv6 Neighbor Discovery Protocol (NDP) is used by IPv6 nodes to discover neighboring devices, routers, and link-layer information. NDP operates using ICMPv6 messages and performs functions that are associated with ARP, router discovery, and related mechanisms in IPv4. Neighbor Solicitation and Neighbor Advertisement messages are used for neighbor discovery and address resolution, while Router Solicitation and Router Advertisement messages support router discovery and address configuration. DHCPv4 is an IPv4 configuration protocol, FTP provides file transfer, and SNMP supports management. Therefore, NDP is the appropriate IPv6 protocol for local neighbor and router discovery.

Question 312. Which command displays the IPv4-to-MAC address mappings stored in a Cisco device’s ARP cache?

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

Correct Answer: 3. show arp

Explanation :-

The show arp command displays ARP entries maintained by a Cisco device. These entries associate IPv4 addresses with corresponding MAC addresses and typically include the interface through which the device can reach the destination. The ARP cache is used when an IPv4 device needs to determine the Layer 2 destination address for a local Ethernet transmission. show mac address-table displays Layer 2 MAC learning on a switch, show ip route displays routes, and show vlan brief displays VLAN information. Therefore, show arp is the correct command for viewing IPv4-to-MAC mappings.

Question 313. Which routing protocol uses hop count as its primary metric?

1. OSPF
2. RIP
3. BGP
4. NTP

Correct Answer: 2. RIP

Explanation :-

Routing Information Protocol (RIP) uses hop count as its routing metric. Each router traversed toward a destination adds one hop to the route’s metric, and RIP considers a maximum of 15 hops reachable, with 16 representing an unreachable destination. OSPF uses a cost metric based primarily on interface bandwidth, while BGP uses a collection of path attributes to select routes. NTP is not a routing protocol at all; it synchronizes clocks. Although RIP is simple to configure, its hop-count metric and limited maximum path length restrict its suitability for larger networks. Therefore, RIP is the correct answer.

Question 314. Which feature allows multiple VLANs to traverse a single switch-to-switch Ethernet link?

1. Port security
2. DHCP snooping
3. EtherChannel
4. 802.1Q trunking

Correct Answer: 4. 802.1Q trunking

Explanation :-

IEEE 802.1Q trunking allows multiple VLANs to traverse a single Ethernet link by adding VLAN identification information to frames. A trunk link is commonly used between switches, allowing traffic belonging to several VLANs to share the same physical connection while remaining logically separated. Access ports normally carry traffic for a single VLAN. Port security controls MAC addresses, DHCP snooping helps protect against rogue DHCP servers, and EtherChannel combines multiple physical links into one logical link. Therefore, 802.1Q trunking is the technology that enables multiple VLANs to cross one Ethernet link.

Question 315. Which command displays information about the Cisco IOS software version and device uptime?

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

Correct Answer: 1. show version

Explanation :-

The show version command provides information about the Cisco IOS software version, device model, uptime, processor and memory information, configuration register, and other system details. It is commonly used when troubleshooting or documenting the software and hardware environment of a Cisco device. show interfaces provides detailed interface statistics, show vlan brief displays VLAN information, and show ip route displays the IPv4 routing table. Therefore, show version is the correct command for checking IOS software version and device uptime.

Question 316. Which type of IPv4 address is 127.0.0.1?

1. Broadcast address
2. Loopback address
3. Multicast address
4. Link-local address

Correct Answer: 2. Loopback address

Explanation :-

The IPv4 address 127.0.0.1 is the commonly used loopback address. Traffic sent to this address remains within the local host and is used to test the local TCP/IP protocol stack without requiring communication through a physical network interface. The entire 127.0.0.0/8 range is reserved for loopback purposes. A broadcast address is used to reach multiple hosts, multicast addresses identify groups of receivers, and link-local addresses use the 169.254.0.0/16 range. Therefore, 127.0.0.1 is correctly classified as a loopback address.

Question 317. Which Cisco feature restricts the MAC addresses that are allowed to use a switch port?

1. Port security
2. NTP
3. NAT
4. CDP

Correct Answer: 1. Port security

Explanation :-

Switch port security can restrict which MAC addresses are permitted to use a particular switch port. Administrators can configure secure MAC addresses manually or allow the switch to learn secure addresses dynamically, depending on the configuration. Port security can also define actions for security violations, such as restricting traffic or placing the port into an error-disabled state. NTP synchronizes time, NAT translates IP addresses, and CDP discovers directly connected Cisco devices. Therefore, port security is the Cisco feature specifically designed to control which MAC addresses are allowed on a switch port.

Question 318. Which protocol is commonly used to synchronize the time on Cisco network devices?

1. ARP
2. DNS
3. NTP
4. STP

Correct Answer: 3. NTP

Explanation :-

Network Time Protocol (NTP) synchronizes the clocks of network devices with a trusted time source. Accurate time is important for logging, troubleshooting, authentication, certificates, and correlating events across multiple devices. Cisco devices can be configured to use an NTP server or another appropriate time source. NTP commonly uses UDP port 123. ARP resolves IPv4 addresses to MAC addresses, DNS resolves hostnames, and STP prevents Layer 2 switching loops. Therefore, NTP is the protocol used to synchronize the time maintained by Cisco network devices.

Question 319. Which protocol is used to transfer files between network devices without providing the encryption features of SSH-based file transfer?

1. SFTP
2. TFTP
3. SSH
4. NTP

Correct Answer: 2. TFTP

Explanation :-

Trivial File Transfer Protocol (TFTP) is a simple file-transfer protocol commonly used in network environments for tasks such as transferring Cisco configuration files or IOS images when supported. TFTP is lightweight but does not provide the encryption and authentication capabilities associated with secure protocols such as SFTP over SSH. SFTP provides secure file transfer through SSH, while SSH itself provides secure remote access and NTP provides time synchronization. TFTP commonly uses UDP port 69. Therefore, TFTP is the protocol described in the question.

Question 320. Which command saves a Cisco device’s current configuration to the startup configuration?

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

Correct Answer: 1. copy running-config startup-config

Explanation :-

The copy running-config startup-config command saves the active running configuration from RAM into the startup configuration stored in NVRAM. Saving the configuration is important because changes made only to the running configuration can be lost when the device reloads or loses power. The show startup-config command only displays the saved configuration, erase startup-config removes it, and reload restarts the device. Therefore, copy running-config startup-config is the correct command for preserving the current configuration across a reboot.