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Question 61. Which command displays the current VLAN configuration and VLAN membership on a Cisco switch?

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

Correct Answer: 4. show vlan brief

Explanation :-

The show vlan brief command provides a concise summary of VLANs configured on a Cisco switch and identifies access ports associated with each VLAN. It is useful for verifying whether a VLAN exists and whether switch interfaces have been assigned to the expected VLAN. The command does not display the routing table, ARP table, or detailed interface counters. VLAN verification is important when troubleshooting connectivity between hosts because devices placed in different VLANs require Layer 3 routing to communicate. Administrators can combine show vlan brief with trunk and interface commands to verify end-to-end VLAN configuration.

Question 62. Which IPv4 address represents the network address for the subnet 192.168.10.0/24?

1. 192.168.10.255
2. 192.168.10.0
3. 192.168.10.1
4. 192.168.11.0

Correct Answer: 2. 192.168.10.0

Explanation :-

For the 192.168.10.0/24 subnet, the first 24 bits identify the network and the final 8 bits identify hosts. Therefore, 192.168.10.0 is the network address. 192.168.10.255 is the broadcast address, while 192.168.10.1 is a usable host address in a traditional IPv4 subnet. 192.168.11.0 belongs to a different /24 network. Correctly identifying network and broadcast addresses is essential for subnet planning and troubleshooting because these addresses have special purposes and are not normally assigned to individual hosts.

Question 63. Which Cisco IOS command enters privileged EXEC mode from user EXEC mode?

1. enable
2. configure terminal
3. login
4. privilege exec

Correct Answer: 1. enable

Explanation :-

The enable command is used to move from user EXEC mode to privileged EXEC mode on a Cisco IOS device. Depending on the configuration, the device may prompt for an enable password or secret. Privileged EXEC mode provides access to additional monitoring commands and allows the administrator to enter global configuration mode. The configure terminal command is normally used after entering privileged EXEC mode. login is associated with authentication configuration on lines, while privilege exec is not the standard command used to enter privileged EXEC mode. Understanding IOS command modes is fundamental to Cisco device administration.

Question 64. Which protocol is used to automatically synchronize the time between network devices?

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

Correct Answer: 3. NTP

Explanation :-

Network Time Protocol (NTP) synchronizes clocks between networked devices and time sources. Consistent time is important for interpreting logs, correlating security events, troubleshooting, certificate operations, and maintaining reliable monitoring information. An NTP client can synchronize with a configured NTP server and adjust its clock according to the received time information. FTP transfers files, DNS resolves domain names, and ARP maps IPv4 addresses to MAC addresses on local networks. Proper time synchronization is especially important in enterprise environments where administrators need to compare events recorded by multiple network and security devices.

Question 65. What is the purpose of a loopback interface on a router?

1. To provide a stable logical interface that is not tied to a physical port
2. To replace every physical Ethernet interface
3. To provide wireless connectivity
4. To convert IPv4 addresses into MAC addresses

Correct Answer: 1. To provide a stable logical interface that is not tied to a physical port

Explanation :-

A loopback interface is a logical interface that remains available independently of the physical state of a particular Ethernet or serial port. It can be used for management, router identification, routing-protocol purposes, and other applications that benefit from a stable IP address. Because a loopback interface is not physically connected to a single network cable, it can remain operational as long as the router has appropriate active interfaces and routes. Loopbacks do not provide wireless connectivity or perform address resolution. They are particularly useful in routing protocols and network-management designs.

Question 66. Which protocol prevents switching loops by placing redundant Layer 2 paths into a blocking state?

1. DHCP
2. STP
3. DNS
4. NAT

Correct Answer: 2. STP

Explanation :-

Spanning Tree Protocol (STP) prevents Layer 2 loops by calculating a loop-free logical topology and placing selected redundant interfaces into a blocking state. Redundant physical paths can then remain available for failover without continuously forwarding frames through a loop. Without STP or another loop-prevention mechanism, Ethernet loops can cause broadcast storms, duplicate frames, and unstable MAC address tables. DHCP provides host configuration, DNS performs name resolution, and NAT translates addressing information. STP is therefore a critical component of resilient switched Ethernet networks where redundant links are intentionally deployed.

Question 67. Which IPv4 address is the limited broadcast address?

1. 0.0.0.0
2. 127.0.0.1
3. 255.255.255.255
4. 224.0.0.1

Correct Answer: 3. 255.255.255.255

Explanation :-

The IPv4 address 255.255.255.255 is the limited broadcast address. Packets sent to this address are intended for all IPv4 hosts on the local network segment and are not forwarded by routers. 127.0.0.1 is the local loopback address, 0.0.0.0 has several special uses depending on context, and 224.0.0.1 is an IPv4 multicast address for all hosts on a local subnet. Understanding the distinction between broadcast, multicast, unicast, and special-purpose addresses is important when analyzing packet behavior and network traffic.

Question 68. Which command displays the IP-to-MAC address mappings learned by a Cisco device?

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

Correct Answer: 1. show arp

Explanation :-

The show arp command displays the Address Resolution Protocol table on a Cisco device. It can show mappings between IPv4 addresses and corresponding MAC addresses, along with associated interfaces and other information. This table helps a network administrator determine whether a device has resolved the Layer 2 address required to deliver IPv4 traffic locally. show ip route displays Layer 3 routes, show vlan brief displays VLAN information, and show cdp neighbors identifies Cisco neighbors. ARP-table information can be especially useful when investigating local connectivity and address-resolution problems.

Question 69. Which routing protocol is commonly classified as a distance-vector protocol?

1. OSPF
2. IS-IS
3. RIP
4. CDP

Correct Answer: 3. RIP

Explanation :-

Routing Information Protocol (RIP) is classified as a distance-vector routing protocol. It uses hop count as its routing metric and periodically exchanges routing information with neighboring routers. RIP has a maximum usable hop count of 15, which limits its scalability compared with protocols designed for larger networks. OSPF and IS-IS are link-state routing protocols, while CDP is a Cisco neighbor-discovery protocol rather than a routing protocol. Understanding routing-protocol categories helps administrators recognize how protocols exchange information and calculate routes.

Question 70. Which command can be used to verify whether a Cisco interface is administratively disabled?

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

Correct Answer: 3. show interfaces

Explanation :-

The show interfaces command provides detailed interface information, including whether an interface is administratively down. An administratively down state generally indicates that the interface has been disabled using the shutdown command. The command also provides line-protocol status, counters, errors, traffic statistics, and other operational information. show ip route displays routing information, show vlan brief summarizes VLANs, and show users displays active user sessions. Checking interface status is an important first step when troubleshooting a connectivity problem involving a specific Cisco interface.

Question 71. Which technology allows a router to use one physical interface to route traffic for multiple VLANs?

1. Router-on-a-stick
2. Port security
3. EtherChannel
4. DHCP snooping

Correct Answer: 1. Router-on-a-stick

Explanation :-

Router-on-a-stick is a configuration in which a single physical router interface uses multiple subinterfaces to provide Layer 3 routing for multiple VLANs. The connection between the switch and router is normally configured as an 802.1Q trunk so that VLAN-tagged traffic can reach the appropriate router subinterface. Each subinterface can be assigned an IP address that serves as the default gateway for its VLAN. Port security controls access to switch ports, EtherChannel combines links, and DHCP snooping helps protect DHCP operations. Router-on-a-stick is useful when inter-VLAN routing is needed without a dedicated physical router interface for every VLAN.

Question 72. Which IPv6 address prefix is reserved for link-local addresses?

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

Correct Answer: 4. FE80::/10

Explanation :-

IPv6 link-local addresses use the FE80::/10 prefix. These addresses are intended for communication on the local link and are not routed between networks. They are automatically configured or otherwise assigned to IPv6-enabled interfaces and are required for several IPv6 functions, including Neighbor Discovery. 2000::/3 identifies global unicast addresses, FC00::/7 is associated with unique local addresses, and FF00::/8 identifies multicast addresses. Recognizing IPv6 prefixes allows administrators to determine the intended scope and routing behavior of an address.

Question 73. Which security feature can inspect DHCP messages and help prevent unauthorized DHCP servers from operating on a switch network?

1. NAT
2. DHCP snooping
3. Port mirroring
4. CDP

Correct Answer: 2. DHCP snooping

Explanation :-

DHCP snooping is a Layer 2 security feature that allows a switch to distinguish trusted and untrusted interfaces for DHCP traffic. DHCP server messages received on untrusted ports can be blocked, helping prevent unauthorized DHCP servers from providing incorrect network configuration to clients. DHCP snooping can also build a binding database containing information such as client MAC addresses, IP addresses, VLANs, and switch ports. NAT performs address translation, port mirroring copies traffic for analysis, and CDP provides device discovery. DHCP snooping can also support other security mechanisms that use its binding information.

Question 74. Which protocol is commonly used to transfer files between network devices without establishing a full TCP connection?

1. TFTP
2. SSH
3. HTTPS
4. SMTP

Correct Answer: 1. TFTP

Explanation :-

Trivial File Transfer Protocol (TFTP) is a lightweight file-transfer protocol that uses UDP rather than TCP. It is commonly associated with network-device operations such as transferring configuration files or software images in environments where its simple design is appropriate. TFTP does not provide the authentication and encryption capabilities of secure file-transfer protocols. SSH provides secure remote access, HTTPS provides secure web communication, and SMTP is used for email transport. Because TFTP has limited security features, administrators should use it only in appropriately controlled network environments.

Question 75. What is the main purpose of EtherChannel on a Cisco switch?

1. To create a single logical link from multiple physical links
2. To assign IP addresses automatically
3. To replace routing protocols
4. To encrypt Ethernet frames

Correct Answer: 1. To create a single logical link from multiple physical links

Explanation :-

EtherChannel combines multiple physical Ethernet links into one logical link. This can increase available bandwidth and provide redundancy because traffic can continue using remaining member links if one physical link fails. Protocols such as LACP can negotiate and maintain EtherChannel membership. Because the bundled interfaces are treated as a logical connection, EtherChannel can also reduce the risk of certain STP topology issues associated with having multiple independent parallel links. EtherChannel does not assign IP addresses, replace routing protocols, or inherently encrypt Ethernet frames.

Question 76. Which command displays the configuration stored in NVRAM on a Cisco IOS 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 on a Cisco IOS device. This configuration is normally loaded when the device boots. In contrast, show running-config displays the active configuration currently held in RAM. Understanding the difference is important because configuration changes made to the running configuration are not automatically preserved across a reload. show version provides software and hardware information, while show flash displays information about files stored in flash memory. Administrators should verify that important configuration changes have been saved before restarting a device.

Question 77. Which protocol is responsible for reliable delivery, sequencing, and retransmission of data at the transport layer?

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

Correct Answer: 3. TCP

Explanation :-

Transmission Control Protocol (TCP) provides reliable, connection-oriented transport services. It uses mechanisms such as sequence numbers, acknowledgments, retransmissions, and flow control to ensure that data is delivered in an ordered and reliable manner. UDP provides connectionless transport without TCP’s built-in reliability mechanisms. ARP operates with IPv4 address resolution on local networks, while ICMP is used for control and diagnostic messaging. Applications that require reliable ordered delivery, such as many web, email, and file-transfer services, commonly use TCP at the transport layer.

Question 78. Which Cisco IOS command can display information about the device’s uptime and IOS version?

1. show vlan
2. show version
3. show arp
4. show interfaces status

Correct Answer: 2. show version

Explanation :-

The show version command provides important system information, including the Cisco IOS software version, device model, system uptime, hardware details, and boot information. Administrators frequently use it when verifying software versions, troubleshooting unexpected behavior, or checking how long a device has been running since its last restart. show vlan focuses on VLAN configuration, show arp displays ARP information, and show interfaces status summarizes switch-port status. Knowing the correct verification command helps administrators obtain relevant operational information efficiently during network troubleshooting.

Question 79. Which IPv4 subnet mask provides 62 usable host addresses in a traditional subnet?

1. 255.255.255.192
2. 255.255.255.224
3. 255.255.255.240
4. 255.255.255.252

Correct Answer: 1. 255.255.255.192

Explanation :-

The subnet mask 255.255.255.192 corresponds to a /26 prefix. A /26 subnet contains 64 total IPv4 addresses, with one address reserved for the network identifier and one for the broadcast address in traditional subnetting. This leaves 62 usable host addresses. A /27 provides 30 usable hosts, /28 provides 14, and /30 provides 2. Understanding subnet capacity is important when determining which prefix length is appropriate for a network segment. Subnetting allows administrators to allocate address space efficiently while maintaining appropriate network boundaries.

Question 80. What is the primary purpose of an IP routing table?

1. To store Ethernet MAC addresses
2. To determine where packets should be forwarded toward their destinations
3. To assign VLAN numbers to switch ports
4. To store user passwords

Correct Answer: 2. To determine where packets should be forwarded toward their destinations

Explanation :-

An IP routing table contains information that a Layer 3 device uses to determine how packets should be forwarded toward destination networks. Entries can be learned through connected interfaces, static routes, or dynamic routing protocols. When a packet arrives, the router compares the destination IP address with routing-table entries and selects the most specific applicable route. A switch’s MAC address table serves a different Layer 2 forwarding purpose, while VLAN assignments and passwords are maintained through other configuration mechanisms. Understanding routing-table operation is essential for analyzing how traffic moves between IP networks.