Cisco 200-301 Cisco Certified Network Associate (CCNA) Exam Dumps and Practice Test Questions Set 7 Q91-105
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Question 91
Which protocol provides automatic IP address assignment for hosts?
A) DHCP
B) DNS
C) ARP
D) ICMP
Answer: A) DHCP
Explanation
Dynamic Host Configuration Protocol, commonly known as DHCP, is a fundamental protocol in network management that enables automatic assignment of network configuration parameters to devices on a network. The primary function of DHCP is to provide IP addresses dynamically to hosts, ensuring that each device receives a unique address without requiring manual configuration. Along with IP addresses, DHCP can also supply other critical networking information such as subnet masks, default gateways, and DNS server addresses. By automating these assignments, DHCP greatly reduces the administrative burden on network engineers and helps prevent configuration errors that can occur when IP addresses are manually assigned, such as address conflicts or incorrect subnetting.
When a device connects to a network configured with DHCP, it begins the process by broadcasting a request for configuration information. A DHCP server responds to this request by offering an available IP address from its configured pool, along with the associated network parameters. Once the host accepts the offer, the DHCP server leases the address to the device for a specified period, ensuring that the same address can be reassigned efficiently if the host disconnects or the lease expires. This dynamic allocation model allows networks to scale easily, accommodating temporary devices such as laptops, printers, or mobile devices without manual intervention, while also optimizing the use of IP address space.
In contrast, Domain Name System (DNS) serves a different purpose in networking. DNS translates human-readable domain names into IP addresses so that devices can locate and communicate with each other over a network or the Internet. While DNS is essential for resolving hostnames and facilitating communication between devices, it does not assign IP addresses or other configuration parameters to hosts. DNS operates in conjunction with DHCP in most networks, allowing devices to automatically receive addresses and then resolve names to communicate effectively, but its role is purely in address resolution rather than address assignment.
Address Resolution Protocol (ARP) is another protocol that operates at a different layer. ARP is responsible for mapping IP addresses to MAC addresses within a local network. It allows devices to determine the physical hardware address associated with a given IP address so that Ethernet frames can be correctly delivered. While ARP is critical for local network communication, it does not provide IP addresses, subnet masks, default gateways, or DNS information. Its function is limited to facilitating communication between devices once their IP addresses are already known.
Internet Control Message Protocol (ICMP) is used primarily for network diagnostics. Tools such as ping and traceroute rely on ICMP to test connectivity, measure latency, and detect routing issues. ICMP allows devices to exchange diagnostic messages about network conditions but does not assign IP addresses or network parameters. Its focus is on troubleshooting and monitoring rather than automated configuration.
Because the question specifically addresses the automatic assignment of IP addresses and related network parameters to hosts, the correct answer is DHCP. It is uniquely designed to streamline network management, reduce manual configuration errors, and efficiently allocate IP addresses and other critical networking information to devices on a network, making it indispensable for modern, scalable environments.
Question 92
Which command verifies the path packets take to a destination?
A) traceroute
B) ping
C) show ip route
D) show interfaces
Answer: A) traceroute
Explanation
Traceroute is an essential network diagnostic tool that allows administrators to observe the path that packets take from a source device to a specific destination. Unlike basic connectivity tests, traceroute provides a hop-by-hop view of the network journey, listing each router or intermediate device that the packet traverses along the way. By doing this, it gives detailed visibility into the actual path data follows across the network. This is particularly useful for identifying network bottlenecks, latency issues, or points of failure, because it shows exactly where delays or interruptions occur. Each hop reported by traceroute includes response times, which allow network engineers to determine whether any segment of the route is unusually slow or experiencing packet loss. This granular insight is invaluable for troubleshooting complex networks, especially those spanning multiple segments or geographic locations.
In contrast, the ping command serves a different but complementary purpose. Ping is designed to test basic connectivity between a source and a destination by sending Internet Control Message Protocol (ICMP) echo requests and measuring the time it takes for echo replies to return. While ping is useful for verifying whether a device is reachable and for assessing overall latency, it does not reveal the path that packets take to reach the destination. Ping cannot show which routers or intermediate devices the data passes through, nor can it indicate where along the path any delays or failures may occur. As a result, while ping can confirm the presence or absence of connectivity, it provides much less information for in-depth network analysis compared to traceroute.
Show ip route is another commonly used command in networking, but it serves a distinct function. This command displays the routing table of the device, listing all known networks, next-hop addresses, and outgoing interfaces. Show ip route provides insight into how a router or switch is configured to forward packets based on network topology and routing protocols. However, it does not actively send packets to trace a path, nor does it measure real-time delays or identify failed hops. The routing table reflects potential paths according to routing decisions, not the actual journey taken by live traffic, making it insufficient when the goal is to observe the specific path packets follow to a destination.
Show interfaces is another command used primarily for monitoring and troubleshooting device interfaces. It provides detailed information about interface status, operational state, IP addressing, errors, and traffic statistics. While this information is critical for diagnosing issues at the interface level, it does not provide visibility into the sequence of devices that packets traverse across a network. It focuses entirely on the local interfaces of the device rather than the end-to-end path of traffic.
Because the question specifically asks about identifying the path from a source device to a destination, traceroute is the correct tool. Its ability to display each intermediate hop and provide timing information makes it uniquely suited for diagnosing network performance, pinpointing bottlenecks, and locating failures along the route. Unlike ping, show ip route, or show interfaces, traceroute actively maps the network path, giving a complete view of how packets travel from source to destination and allowing administrators to take targeted corrective actions when problems are detected.
Question 93
Which command removes all VLANs from a Cisco switch except VLAN 1?
A) delete vlan.dat
B) erase startup-config
C) reload
D) show vlan brief
Answer: A) delete vlan.dat
Explanation
In Cisco network devices, VLANs are used to segment network traffic logically, allowing administrators to group devices, enhance security, and improve network performance. Sometimes, it becomes necessary to remove VLANs entirely from a switch, either to reconfigure the network or to clear incorrect or outdated VLAN assignments. The command delete vlan.dat is specifically designed for this purpose. Executing this command removes the VLAN database file stored on the switch, effectively deleting all VLANs that have been configured, except for the default VLAN 1, which cannot be removed. This process ensures that all non-default VLAN configurations, including their names and associated ports, are erased, allowing administrators to start fresh with a clean VLAN configuration. Removing the VLAN database is a critical step in network reconfiguration or when recovering a switch from misconfigured VLAN settings.
In contrast, the command erase startup-config serves a different function. When erase startup-config is executed, it deletes the configuration file stored in NVRAM, which contains all saved settings applied to the switch. While this command clears the running configurations that define interface settings, IP addresses, routing, and other administrative configurations, it does not affect the VLAN database stored in vlan.dat. As a result, VLANs that were previously created remain intact even after the startup configuration is erased, making erase startup-config insufficient for completely removing VLANs.
The reload command is another commonly used tool for network device management. Reload restarts the device, reinitializing hardware and software components and loading the startup configuration from NVRAM. While reloading a switch can resolve certain operational issues and apply configuration changes, it does not delete VLANs. VLAN information is retained across reloads because it is stored in the vlan.dat file, separate from the startup configuration. Therefore, relying on reload alone will not remove VLANs and is not an appropriate method for clearing VLAN data.
Show vlan brief is a diagnostic command used to display current VLAN information on a switch. It provides all VLANs configured, their names, status, and the ports assigned to each VLAN. This command is essential for monitoring VLAN configurations and verifying network setup, but it is purely informational. Show vlan brief does not modify or delete any VLANs and cannot be used to clear VLAN configurations.
Because the question specifically asks for removing VLANs from a switch, delete vlan.dat is the correct command. It directly targets the VLAN database, erasing all user-configured VLANs while leaving only the default VLAN 1. Unlike erase startup-config, reload, or show vlan brief, delete vlan.dat ensures that the VLAN structure is completely cleared, enabling administrators to reconfigure the network from a clean state. This makes it the precise and necessary action when the goal is to remove VLANs entirely from a switch, providing a reliable method to reset VLAN configurations and avoid conflicts or misconfigurations in network segmentation.
Question 94
Which routing protocol is link-state and supports VLSM?
A) OSPF
B) RIP v1
C) IGRP
D) BGP
Answer: A) OSPF
Explanation
Open Shortest Path First, or OSPF, is a widely used interior gateway routing protocol that operates as a link-state protocol. Its design allows it to maintain an accurate map of the network topology by exchanging information about directly connected links with other OSPF-enabled routers. This link-state approach enables OSPF to make highly informed routing decisions, as each router builds its own complete picture of the network and uses the Shortest Path First (SPF) algorithm to calculate optimal routes. One of the key advantages of OSPF is its support for Classless Inter-Domain Routing (CIDR) and Variable Length Subnet Masking (VLSM). This means that OSPF can handle networks with different subnet masks, allowing for more efficient use of IP address space. By accommodating VLSM, OSPF ensures that IP addresses are allocated according to actual need rather than being constrained by fixed classful boundaries, which reduces waste and allows for more granular network design.
Another important characteristic of OSPF is its fast convergence. Because each router in an OSPF network maintains a complete map of the network, changes such as link failures or new routes are quickly propagated to all routers through Link State Advertisements (LSAs). This rapid dissemination of topology information allows routers to recalculate optimal paths almost immediately, minimizing downtime and improving overall network reliability. The combination of VLSM support, classless routing, and fast convergence makes OSPF a highly efficient and scalable choice for medium- to large-sized networks, where routing accuracy and speed are critical.
In contrast, Routing Information Protocol version 1 (RIP v1) operates as a distance-vector protocol and is classful. Because it does not support VLSM or CIDR, RIP v1 cannot distinguish between subnets of different sizes within the same major network class. This limitation makes RIP v1 less efficient in terms of IP address usage, particularly in networks that require variable subnet sizes or hierarchical addressing. Additionally, RIP v1 converges more slowly than OSPF because updates are propagated periodically rather than immediately upon changes in the network topology.
Interior Gateway Routing Protocol (IGRP), another classful protocol developed by Cisco, also does not support VLSM. While IGRP provides some enhancements over RIP in terms of scalability and metrics, its classful nature means that it cannot accommodate variable subnetting within the same network, leading to less flexible address allocation. Like RIP, IGRP is slower to converge compared to OSPF and is generally considered less suitable for modern, complex networks.
Border Gateway Protocol (BGP) is an exterior gateway protocol used primarily for routing between autonomous systems on the Internet. BGP is a path vector protocol, not a link-state protocol, and it is designed to make policy-based routing decisions based on path attributes rather than the shortest path. BGP’s focus is inter-domain routing, making it unsuitable for internal network routing where link-state protocols like OSPF excel.
Because the question specifies a link-state routing protocol that supports VLSM and efficient IP address utilization, OSPF is the correct choice. Its combination of link-state intelligence, fast convergence, and classless routing capabilities makes it uniquely suited to meet these requirements.
Question 95
Which type of cable is used for console access to a router or switch?
A) Rollover
B) Straight-through
C) Crossover
D) Fiber patch
Answer: A) Rollover
Explanation
Rollover cables are a specialized type of cable used extensively in network administration for configuring and managing Cisco devices. These cables are specifically designed to connect a computer’s serial port to the console port of a router, switch, or other network equipment. The console port serves as a dedicated management interface that allows administrators to access the device’s command-line interface (CLI) directly. Unlike network ports used for regular data transmission, the console port provides out-of-band management, meaning that it allows configuration and troubleshooting even if the device’s network interfaces are not functioning. This makes the rollover cable an essential tool for initial device setup, troubleshooting, and recovery operations.
The physical design of a rollover cable is unique. It is called a “rollover” because the wiring inside the cable is reversed, or rolled over, from one end to the other. Pin 1 on one end connects to pin 8 on the other end, pin 2 connects to pin 7, and so on. This reversal distinguishes it from other common cable types, ensuring that the signals align correctly between the PC’s serial interface and the console port. Without a rollover cable or an appropriate USB-to-serial adapter for modern computers, administrators would be unable to establish direct console access to the device, which is critical for performing tasks such as loading initial configurations, upgrading IOS images, or recovering from failed configurations.
In comparison, straight-through cables are used for connecting devices of different types, such as a PC to a switch or a switch to a router. These cables transmit data in a one-to-one wiring configuration and are essential for standard network connectivity, but they are not suitable for console access because they do not reverse the necessary pins. While straight-through cables form the backbone of everyday network communication, they cannot facilitate direct device management through a console port.
Crossover cables, on the other hand, are designed to connect similar devices directly, such as switch-to-switch or router-to-router connections. These cables reverse the transmit and receive pairs to enable direct device-to-device communication without an intermediate networking device. While crossover cables are important in specific network topologies and for certain types of direct communication, they are not intended for console access or device configuration purposes.
Fiber patch cables are another category entirely, used to connect devices over optical fiber links. They are critical for high-speed, long-distance data transmission in modern networks, but they serve a completely different purpose and are incompatible with serial console interfaces. Fiber patch cables cannot be used for direct management or configuration of a network device through a console port.
Because the question specifically focuses on accessing the console port of a device for configuration and management, the correct cable type is a rollover cable. Its design, purpose, and pinout configuration make it uniquely suited for establishing a direct, out-of-band connection between a PC and a network device. Unlike straight-through, crossover, or fiber cables, rollover cables enable administrators to perform critical configuration, monitoring, and troubleshooting tasks directly on the device, ensuring proper setup and ongoing management of the network infrastructure.
Question 96
Which type of IPv6 address allows communication with the nearest of multiple identical addresses?
A) Anycast
B) Unicast
C) Multicast
D) Link-Local
Answer: A) Anycast
Explanation
Anycast is a network addressing and routing technique that allows a single IP address to be assigned to multiple interfaces, which can reside on different devices or in geographically distributed locations. The primary characteristic of anycast is that when a packet is sent to an anycast address, the network delivers it to the nearest interface that holds that address based on routing metrics such as hop count, latency, or path cost. This method provides an efficient way to route traffic to the closest or most optimal server, improving response times and enhancing overall network performance. Anycast is commonly used in distributed services like Domain Name System (DNS) servers, content delivery networks (CDNs), and load balancing, where users benefit from connecting to the nearest available resource automatically. By directing traffic to the closest instance, anycast reduces latency, balances load across multiple servers, and provides redundancy in case one of the nodes becomes unavailable.
In contrast, unicast communication is designed for one-to-one transmission. A unicast address represents a single network interface on a device, and packets sent to a unicast address are delivered exclusively to that interface. This method is ideal for standard point-to-point communications, such as web browsing, file transfers, or email delivery. While unicast ensures that data reaches a specific destination, it does not provide the benefits of proximity-based routing or automatic distribution that anycast offers. Each unicast transmission must be handled individually, without consideration of multiple potential receivers or shortest-path optimization across the network.
Multicast, on the other hand, serves a one-to-many communication model. A multicast address allows a single sender to transmit packets to all members of a designated group who have subscribed to that address. This is particularly efficient for applications like streaming video, live broadcasts, and online conferencing, where the same data needs to reach multiple receivers simultaneously. While multicast efficiently delivers data to a group, it does not consider which recipient is “closest” or optimize routing for proximity. It simply ensures that all subscribed devices receive the same information.
Link-local addresses have a much more limited scope. They are used exclusively for communication between devices on the same local network segment, or link. Link-local addresses cannot be routed across different networks, making them suitable only for local device discovery, configuration, or limited communications within a subnet. While useful in specific contexts such as neighbor discovery or automatic IP configuration, link-local addresses do not provide global reachability or one-to-nearest delivery functionality.
Because the question specifically refers to one-to-nearest communication, anycast is the correct choice. Unlike unicast, which targets a single interface, multicast, which targets multiple subscribers, or link-local, which is restricted to a local network segment, anycast provides the unique capability of delivering packets to the nearest member of a group. This makes it ideal for distributed services, improving latency, reliability, and load balancing by automatically routing users to the most optimal location. Anycast’s proximity-based routing is its defining feature, distinguishing it from other addressing and delivery methods.
Question 97
Which command displays the ARP table on a Cisco device?
A) show arp
B) show mac address-table
C) show ip route
D) show interfaces
Answer: A) show arp
Explanation
The command show arp is an essential tool for network administrators because it provides a detailed mapping between IP addresses and MAC addresses on a local network. This mapping is maintained in the Address Resolution Protocol (ARP) table, which the device uses to determine the correct Layer 2 address for a given Layer 3 IP address. By displaying this information, show arp allows administrators to verify that devices on the network are reachable and correctly associated with their physical addresses. This is particularly useful when troubleshooting connectivity issues, diagnosing IP conflicts, or confirming that ARP requests and responses are functioning properly. Understanding the contents of the ARP table helps ensure that communication within a local subnet is operating as expected, which is critical for maintaining a healthy network environment.
In comparison, the command show mac address-table provides information about MAC addresses that a switch has learned and the specific ports associated with each address. While this information is valuable for identifying which devices are connected to which switch ports and for diagnosing Layer 2 connectivity issues, it does not provide the mapping between IP addresses and MAC addresses. Because show mac address-table focuses solely on Layer 2 addresses and port associations, it cannot answer questions related to ARP or IP-to-MAC relationships.
The command show ip route, on the other hand, displays the routing table of the device. This table includes networks that are known to the router, the next-hop addresses, and the interfaces used to reach those networks. Show ip route is essential for understanding how traffic is forwarded across different subnets or routed between networks, but it does not provide any information about the specific MAC addresses associated with IP addresses. Therefore, it is not useful when the goal is to examine ARP information or troubleshoot local address resolution issues.
Show interfaces is another important command, but it serves a different purpose. It provides detailed statistics for each interface on the device, including operational status, IP addresses assigned to interfaces, error counts, and traffic statistics. This command is very useful for diagnosing interface-level problems, such as packet drops, collisions, or misconfigurations. However, show interfaces does not display the ARP table or provide information about IP-to-MAC mappings, so it cannot be used to directly troubleshoot issues related to address resolution.
Because the question specifically asks for information related to ARP, the correct command is show arp. This command directly displays the table of IP addresses and their corresponding MAC addresses, which is essential for verifying device reachability within a subnet and for troubleshooting communication problems between devices on a local network. Unlike show mac address-table, show ip route, or show interfaces, show arp provides the precise information needed to understand how IP addresses are resolved to physical addresses, making it the correct choice for questions focused on ARP information.
Question 98
Which command displays interface status and IP addresses in a concise format?
A) show ip interface brief
B) show running-config
C) show version
D) ping
Answer: A) show ip interface brief
Explanation
Show ip interface brief lists interfaces with IP addresses, operational status, and protocol status concisely.
Show running-config shows the configuration.
Show version shows IOS version and system info.
Ping tests connectivity.
Since the question asks for a concise interface overview, show ip interface brief is correct.
Question 99
Which protocol provides one-to-many communication to devices subscribed to a group?
A) Multicast
B) Unicast
C) Anycast
D) Broadcast
Answer: A) Multicast
Explanation
Multicast is a method of communication in networking that allows a single sender to transmit packets to multiple receivers simultaneously, but only to those devices that have explicitly expressed interest in receiving that traffic. This is often referred to as one-to-many communication, and it is an efficient way to deliver information to a specific group of recipients without overwhelming the entire network. Multicast is commonly used in applications such as video conferencing, live streaming, IPTV, and stock market data distribution, where the same data needs to be delivered to multiple endpoints at the same time. By sending a single copy of the data onto the network and allowing network infrastructure to replicate it only where necessary, multicast reduces overall bandwidth consumption compared to sending multiple individual copies, making it a highly efficient method of data distribution in large-scale networks.
In contrast, unicast communication is a one-to-one transmission model. In unicast, a sender transmits data directly to a single specific recipient. Each additional recipient requires a separate transmission of the same data. While unicast is suitable for standard web browsing, file transfers, and email, it becomes inefficient when the same content needs to reach multiple devices because the sender must generate multiple copies of the data, consuming more bandwidth and network resources. Therefore, unicast is not ideal for applications that require simultaneous delivery to multiple receivers.
Anycast is another method that is distinct from multicast and unicast. In anycast communication, data is sent to the nearest or most optimal member of a group of devices that share the same address. Anycast is often used for load balancing and redundancy, particularly in distributed networks such as content delivery networks (CDNs) and DNS services. While it allows for efficient routing to the closest node, it is not intended for delivering the same data to multiple recipients simultaneously. Its purpose is primarily to direct traffic to a single, nearest receiver, making it fundamentally different from multicast, which targets multiple receivers intentionally.
Broadcast, on the other hand, is designed to send data to all devices within a specific network segment or subnet. Every device on the subnet receives the broadcast message, regardless of whether it requires the information. Broadcast is commonly used for discovery protocols, address resolution, and network announcements. Although it can reach multiple devices, broadcast lacks the efficiency and specificity of multicast because it sends data indiscriminately, often creating unnecessary traffic and potential network congestion for devices that do not need the information.
Because the question specifically refers to one-to-many communication, multicast is the correct choice. Unlike unicast, which targets a single device, anycast, which targets the nearest device, or broadcast, which targets all devices indiscriminately, multicast delivers data only to those devices that are members of a specific group. This targeted, efficient delivery makes multicast the ideal method for applications where the same data must be received simultaneously by multiple intended recipients, minimizing bandwidth usage while ensuring all subscribed devices receive the information as intended.
Question 100
Which protocol is used to provide reliable delivery for applications requiring ordered data?
A) TCP
B) UDP
C) ICMP
D) ARP
Answer: A) TCP
Explanation
Transmission Control Protocol, or TCP, is one of the core protocols of the Internet protocol suite and plays a critical role in ensuring reliable communication between devices across a network. TCP provides a connection-oriented service, meaning that it establishes a connection between the sending and receiving devices before any actual data is transmitted. This connection ensures that the data sent from one device reaches the other in the correct order and without loss. One of the key mechanisms TCP uses to provide reliability is the use of acknowledgments. When a segment of data is sent, the receiving device responds with an acknowledgment, indicating that the segment has been successfully received. If the acknowledgment is not received within a specified time frame, TCP automatically retransmits the segment. This process of acknowledgment and retransmission ensures that even if some segments are lost due to network congestion, errors, or other issues, all the data will eventually be delivered correctly.
In addition to reliability, TCP ensures that data is delivered in the same order in which it was sent. This ordering is crucial for applications where the sequence of data matters, such as file transfers, web page loading, and email delivery. TCP achieves this by assigning a sequence number to each segment of data. The receiving device uses these sequence numbers to reorder segments if they arrive out of sequence. This combination of acknowledgment, retransmission, and sequencing guarantees that the application layer receives a complete and correctly ordered stream of data, providing a stable and predictable communication environment.
UDP, or User Datagram Protocol, offers a contrasting approach. Unlike TCP, UDP is connectionless and does not provide mechanisms for acknowledgment, retransmission, or ordering. It simply sends datagrams from one device to another without establishing a connection or verifying delivery. While UDP is useful for applications where low latency is critical, such as streaming video, online gaming, or voice over IP, it does not guarantee reliable or ordered delivery. Any lost or out-of-sequence packets are simply discarded or handled by the application itself, rather than by the transport protocol.
ICMP, or Internet Control Message Protocol, serves a completely different purpose. It is primarily used for network diagnostics and error reporting. Tools like ping and traceroute rely on ICMP to test connectivity and measure network performance. ICMP does not provide transport services for application data and does not guarantee delivery or ordering, making it unsuitable for tasks that require reliable transmission.
ARP, or Address Resolution Protocol, operates at a different layer of the network and is responsible for mapping IP addresses to MAC addresses. While ARP is essential for communication within a local network segment, it does not handle transport reliability, sequencing, or acknowledgment of data.
Given these distinctions, TCP is uniquely suited for scenarios that require reliable and ordered delivery of application data. Because the question specifically focuses on reliable, sequential transmission, TCP is the correct protocol. It ensures that data is transmitted accurately and in the proper order, making it indispensable for applications like web browsing, file transfers, and email communication, where data integrity and order are critical.
Question 101
Which command is used to enable a switch port for VLAN traffic?
A) switchport mode access
B) switchport trunk encapsulation dot1q
C) switchport nonegotiate
D) show vlan brief
Answer: A) switchport mode access
Explanation
The command switchport mode access is used on network switches to configure a specific interface as an access port, which allows it to carry traffic for a single VLAN. Access ports are primarily designed for end devices such as personal computers, printers, or IP phones that do not need to understand VLAN tagging. When a port is set to access mode, all incoming and outgoing traffic on that port is associated with the designated VLAN, and the switch ensures that the device connected to the port communicates only within that VLAN. This setup is crucial for segmenting network traffic, enhancing security, and organizing devices into logical groups based on function or department. By configuring a port as an access port, administrators can ensure that devices receive proper VLAN membership and that traffic is appropriately isolated from other VLANs on the network.
The switchport mode access command is simple to configure but essential for maintaining proper VLAN structure and network efficiency. Once a port is set as an access port, it will no longer attempt to negotiate trunking with other devices, ensuring that only untagged frames belonging to the configured VLAN are transmitted and received. This provides a predictable and controlled environment for end devices, preventing accidental VLAN leakage or misconfiguration that could allow devices to access unauthorized network segments. In addition, configuring access ports consistently across a network helps with troubleshooting, monitoring, and applying policies, as each port has a defined role and associated VLAN.
In contrast, the command switchport trunk encapsulation dot1q serves a different purpose. This command specifies the trunking protocol to be used on a port, typically 802.1Q, which is a standard for VLAN tagging on trunk links. Trunk ports are designed to carry traffic for multiple VLANs between switches or other network devices. While setting the encapsulation type is necessary for trunk configuration, it does not configure the port as an access port, nor does it restrict the port to a single VLAN. Trunk configuration is relevant for inter-switch links or uplinks to routers and other devices that handle multiple VLANs, not for end-device connections.
The switchport nonegotiate command is used to disable Dynamic Trunking Protocol (DTP) negotiation on a port. DTP is a protocol that allows switches to negotiate whether a port should operate as a trunk. Disabling DTP can improve security and prevent accidental trunk formation, but this command does not set a port as an access port. It is a supplementary configuration used in specific scenarios where trunking negotiation needs to be controlled.
The show vlan brief command is a monitoring tool that displays VLAN assignments, port status, and basic information about VLAN configurations. While it is useful for verifying which ports belong to which VLANs and checking operational status, it does not actively configure a port for VLAN traffic. It provides visibility rather than configuration.
Because the question specifically asks about enabling a switch port to carry VLAN traffic for end devices, switchport mode access is the correct command. It directly sets the port to access mode, ensures that traffic is confined to a single VLAN, and establishes a controlled environment for network devices, which neither trunk configuration commands nor monitoring commands accomplish. This makes it the most appropriate solution for enabling VLAN traffic on a specific port.
Question 102
Which type of address allows a device to communicate with all devices on the local link in IPv6?
A) Link-local
B) Global unicast
C) Multicast
D) Anycast
Answer: A) Link-local
Explanation
Link-local addresses are a specific type of IPv6 address that are automatically assigned to every interface on an IPv6-enabled device. These addresses, which fall within the FE80::/10 range, are designed to allow communication between devices on the same local link without the need for manual configuration or a global addressing scheme. Link-local addresses play a fundamental role in the operation of IPv6 networks because they provide a reliable way for devices to communicate directly with each other on a single subnet or link. This capability is critical for a variety of network functions, including the initial configuration of devices, neighbor discovery, and the operation of certain routing protocols.
Every IPv6-enabled interface is required to have a link-local address, and these addresses are used for essential protocol operations. For example, the Neighbor Discovery Protocol, which is the IPv6 equivalent of ARP in IPv4, relies on link-local addresses to identify and interact with other devices on the same link. Routing protocols such as OSPFv3 and EIGRP for IPv6 also use link-local addresses to exchange routing information between directly connected routers. By restricting these addresses to the local link, IPv6 ensures that critical communications related to link operations are contained within the subnet and cannot be routed to external networks. This containment provides both security and operational reliability.
In contrast, global unicast addresses in IPv6 are routable on the broader internet and are designed for communication beyond the local link. These addresses are assigned either manually or via dynamic configuration methods such as DHCPv6, and they allow devices to communicate with external networks and the internet. While global unicast addresses are essential for external connectivity, they are not used for local link-specific operations like neighbor discovery or immediate subnet communications. Therefore, global unicast addresses do not fulfill the requirement for one-to-all communication restricted to a local link.
Multicast addresses, on the other hand, target a specific group of devices rather than all devices on a link. IPv6 multicast allows a sender to deliver a packet to multiple receivers that have joined a multicast group. This one-to-many communication is useful for applications such as streaming media, service discovery, and network management, but multicast does not ensure that every device on the local link receives the message unless all devices have joined the group.
Anycast addresses are designed to deliver packets to the nearest device among a set of devices sharing the same address. Anycast is commonly used for load balancing and efficient routing but is not intended for communication with all devices on a local link. Packets sent to an anycast address are routed to a single, typically the closest, recipient, rather than being delivered to every device in the subnet.
Because the question specifies communication with all devices on the local link, link-local addresses are the correct choice. They are automatically assigned, universally present on all IPv6 interfaces, and provide essential functionality for one-to-all communication within the link. Unlike global unicast, multicast, or anycast addresses, link-local addresses are specifically designed to enable reliable communication among all devices on the same subnet, supporting both operational protocols and direct device-to-device interactions.
Question 103
Which command displays the current VLAN configuration and status on a switch?
A) show vlan brief
B) show running-config
C) show interfaces
D) show mac address-table
Answer: A) show vlan brief
Explanation
Show vlan brief displays all VLANs configured on a switch, their IDs, names, and status. It is used to verify VLAN assignment and operational state.
Show running-config displays the full active configuration but is not focused solely on VLAN information.
Show interfaces displays interface status but does not show VLANs in a concise format.
Show mac address-table displays MAC addresses and associated ports but not VLAN details.
Because the question asks for VLAN configuration and status, show vlan brief is correct.
Question 104
Which protocol is used to securely transfer files between network devices?
A) SFTP
B) FTP
C) TFTP
D) HTTP
Answer: A) SFTP
Explanation‘
SFTP (Secure File Transfer Protocol) transfers files securely over SSH, encrypting data and credentials. It is commonly used for device configuration backups and firmware updates.
FTP transfers files without encryption, exposing credentials and data.
TFTP is a simple file transfer protocol with no security and limited features.
HTTP is for web traffic and is not primarily used for file transfers between network devices.
Because the question asks about secure file transfer, SFTP is correct.
Question 105
Which command displays the routing table on a Cisco device?
A) show ip route
B) show ip interface brief
C) show mac address-table
D) show arp
Answer: A) show ip route
Explanation
Show ip route displays the routing table of a device, including connected, static, and dynamically learned routes. It helps troubleshoot network reachability and path selection.
Show ip interface brief displays interface IPs and status.
Show mac address-table shows learned MAC addresses and ports.
Show arp displays IP-to-MAC mappings for local network communications.
Because the question asks specifically for the routing table, show ip route is correct.