View Full Cisco 100-150 Exam Dumps and Practice Test Dumps.

 

Question 301

How does OSPF determine the Designated Router (DR) and Backup Designated Router (BDR) on a multi-access broadcast network segment?

1. By selecting the routers with the highest physical IP addresses configured on their interfaces.
2. By electing the routers with the highest OSPF priority values, breaking ties with the highest Router ID.
3. By selecting the routers that boot up first in the network topology.
4. By electing the routers with the lowest administrative distance values.

Correct Answer: 2

Explanation:

On multi-access broadcast networks like Ethernet, OSPF elects a Designated Router and a Backup Designated Router to minimize the volume of routing protocol traffic by serving as a central collection and distribution point for link-state advertisements. The DR and BDR election is determined by evaluating the OSPF priority value configured on the router interfaces, where a higher numerical value indicates greater preference (defaulting to 1). The router advertising the highest OSPF priority wins the DR role, and the runner-up becomes the BDR. If multiple routers share the exact same priority value—such as the default factory setting of 1—the OSPF algorithm breaks the tie by evaluating their Router IDs, selecting the router with the highest numerical Router ID as the DR. Setting an interface priority to 0 completely prevents that router from participating in the election.

Question 302

Which wireless security protocol replaced the pre-shared key exchange with Simultaneous Authentication of Equals (SAE) to protect against offline dictionary attacks?

1. WPA
2. WPA2
3. WPA3
4. WEP

Correct Answer: 3

Explanation:

Wi-Fi Protected Access 3 introduced significant cryptographic enhancements over WPA2, most notably the implementation of Simultaneous Authentication of Equals (SAE) for personal networks. In traditional WPA2 pre-shared key modes, attackers could capture the initial four-way handshake over the air and execute offline brute-force or dictionary attacks against the static passphrase until the correct key was discovered. WPA3-Personal replaces the vulnerable pre-shared key exchange with SAE, a secure key establishment protocol based on a cryptographic handshake that prevents offline dictionary attacks even if users select weak passwords. Additionally, WPA3 provides forward secrecy, ensuring that encrypted traffic recorded today cannot be decrypted later if the network passphrase is eventually compromised.

Question 303

What is the standard prefix range reserved for IPv6 Global Unicast Addresses?

1. 2000::/3
2. fc00::/7
3. fe80::/10
4. ff00::/8

Correct Answer: 1

Explanation:

In IPv6 architecture, Global Unicast Addresses are globally routable and reachable across the public internet, functioning similarly to public IPv4 addresses. The Internet Assigned Numbers Authority allocates the global unicast address space utilizing the prefix block 2000::/3, which encompasses any address beginning with binary bits 001 (ranging from 2000:: through 3fff:ffff:ffff:ffff:ffff:ffff:ffff:ffff). Other major IPv6 address types include Unique Local Addresses (fc00::/7), Link-Local Addresses (fe80::/10), and Multicast Addresses (ff00::/8). Routers forward global unicast packets seamlessly across global boundaries based on standard hierarchical routing prefix evaluations.

Question 304

What are the three primary operational modes available for VTP (VLAN Trunking Protocol) in Cisco IOS?

1. Active, Passive, Standby
2. Server, Client, Transparent
3. Primary, Secondary, Member
4. Master, Slave, Autonomous

Correct Answer: 2

Explanation:

VLAN Trunking Protocol is a Cisco proprietary messaging protocol used to manage VLAN configurations centrally across an entire switched campus infrastructure by synchronizing VLAN addition, deletion, and naming updates between switches. VTP operates in three distinct modes: Server, Client, and Transparent. In Server mode, administrators can create, modify, or delete VLANs, and these updates are advertised to other switches while being saved in NVRAM. In Client mode, switches synchronize their local VLAN databases with advertisements received from VTP servers, but local modifications cannot be made directly. In Transparent mode, switches do not participate in VTP synchronization or update their own databases from advertisements, but they forward VTP configuration messages transparently across their trunk ports to other switches in the domain.

Question 305

What does the Feasible Distance (FD) represent in EIGRP routing calculations?

1. The metric advertised by a neighboring router to reach a destination network.
2. The lowest calculated total metric along the best path from the local router to a destination network.
3. The absolute maximum hop count permitted before a route is declared unreachable.
4. The cumulative interface delay across secondary backup links.

Correct Answer: 2

Explanation:

In EIGRP routing architecture, Feasible Distance represents the lowest calculated total metric accumulated along the best path from the local router to a specific destination network prefix. The Feasible Distance is computed by taking the advertised metric from the best neighboring router (the Successor) and adding the cost of the link connecting the local router to that neighbor. EIGRP uses the Feasible Distance in its core path selection and loop-prevention algorithms, comparing it against the Reported Distance of alternative neighbors to determine whether those backup paths qualify as valid Feasible Successors capable of instantaneous, loop-free failover.

Question 306

What fundamental capability distinguishes Extended Access Control Lists (ACLs) from Standard ACLs?

1. Extended ACLs filter traffic exclusively based on source IP addresses.
2. Extended ACLs evaluate source IP addresses, destination IP addresses, protocol types, and TCP/UDP port numbers.
3. Extended ACLs can only be applied to loopback management interfaces.
4. Extended ACLs do not enforce an implicit “deny all” rule at the bottom of the list.

Correct Answer: 2

Explanation:

Extended Access Control Lists offer granular traffic filtering capabilities compared to standard ACLs (numbered 1 to 99). Standard ACLs examine only the source IP address of passing packets, requiring them to be placed as close as possible to the destination to avoid unintended blocking. In contrast, Extended ACLs (numbered 100 to 199) evaluate a comprehensive set of packet header parameters, including source and destination IP addresses, upper-layer protocols (such as TCP, UDP, ICMP, or OSPF), and specific source or destination TCP/UDP port numbers (such as HTTP port 80 or SSH port 22). This granular control allows network administrators to enforce precise security policies, block specific application traffic, and isolate network segments effectively at the traffic source.

Question 307

What are the four port roles utilized by the Rapid Spanning Tree Protocol (RSTP)?

1. Root, Designated, Alternate, Backup
2. Blocking, Listening, Learning, Forwarding
3. Master, Slave, Active, Passive
4. Primary, Secondary, Edge, Non-Edge

Correct Answer: 1

Explanation:

The Rapid Spanning Tree Protocol defines four distinct port roles to manage loop-free topology forwarding paths efficiently: Root Port, Designated Port, Alternate Port, and Backup Port. The Root Port is the single best port on a non-root switch providing the lowest cost path toward the root bridge. The Designated Port is the forwarding port on a segment responsible for transmitting traffic toward the root bridge. The Alternate Port serves as a backup to the root port on a switch, receiving superior BPDUs from another bridge and entering a discarding state ready to take over if the primary root port fails. The Backup Port serves as a backup to a designated port on a shared media segment, receiving BPDUs from the local switch itself.

Question 308

What is the total number of usable host IP addresses available in an IPv4 subnet utilizing a /25 CIDR prefix?

1. 62 hosts
2. 126 hosts
3. 254 hosts
4. 510 hosts

Correct Answer: 2

Explanation:

A /25 CIDR prefix corresponds to an IPv4 subnet mask of 255.255.255.128, where twenty-five bits are allocated to network identification and seven bits remain available for host device addressing. To determine the total number of IP addresses in this subnet, calculate two raised to the power of the host bits (two to the power of 7), which yields 128 total addresses in the block. Out of these 128 total addresses, two are permanently reserved for structural functions: the lowest address serves as the network identifier, and the highest address functions as the directed broadcast address. Subtracting these two reserved addresses leaves exactly 126 usable host IP addresses available for assignment to workstations, servers, or router interfaces within that specific subnet range.

Question 309

What is the primary operational function of Dynamic ARP Inspection (DAI) on a Cisco switch?

1. Encrypting ARP reply packets against wireless interception.
2. Preventing ARP poisoning and spoofing attacks by validating ARP packets against trusted DHCP snooping binding databases.
3. Automatically converting static IP addresses into dynamic leases.
4. Translating private internal MAC addresses into public routable IP addresses.

Correct Answer: 2

Explanation:

Dynamic ARP Inspection is a robust Layer 2 security feature that protects enterprise switched networks against ARP spoofing and poisoning attacks. In an ARP poisoning attack, a malicious actor floods the local network with forged Address Resolution Protocol replies, associating their own physical MAC address with the gateway’s IP address to intercept, modify, or drop traffic intended for other hosts. DAI intercepts all ARP packets arriving on untrusted switch ports, compares the source IP and MAC address bindings against trusted entries stored in the DHCP snooping binding database, and drops any packets that fail validation. This prevents unauthorized ARP cache corruption and maintains secure local communication.

Question 310

Which Syslog severity level corresponds to an error condition that requires immediate administrative attention to restore normal operations?

1. Level 1
2. Level 2
3. Level 3
4. Level 4

Correct Answer: 3

Explanation:

Syslog severity levels follow a standardized numerical scale from 0 to 7, where lower numbers indicate higher operational severity. Level 3 corresponds to “Error” (often logged as err), indicating that an error condition has occurred—such as a hardware failure, memory allocation failure, or interface subsystem crash—which impairs normal operational capabilities and requires administrative intervention. The complete scale progresses from Level 0 (Emergency), Level 1 (Alert), Level 2 (Critical), Level 3 (Error), Level 4 (Warning), Level 5 (Notice), Level 6 (Informational), up to Level 7 (Debugging). Error messages trigger syslog alerts to management servers, enabling timely incident response before minor faults escalate into catastrophic system outages.

Question 311

What is the primary function of Spanning Tree Root Guard when configured on a switch port?

1. Preventing unauthorized switches connected to an edge port from becoming the root bridge.
2. Automatically encrypting all BPDU control frames across trunk links.
3. Speeding up port convergence by eliminating the listening state.
4. Restricting switch port access exclusively to authorized static MAC addresses.

Correct Answer: 1

Explanation:

Root Guard is an essential Layer 2 security mechanism in Spanning Tree Protocol deployments designed to protect the predetermined root bridge placement within an enterprise campus network. If an administrator configures Root Guard on a designated port facing access switches or untrusted downstream links, the switch monitors incoming BPDUs on that interface. If a connected device attempts to advertise a superior BPDU (claiming a bridge priority higher or lower enough to become the root bridge), Root Guard intercepts the control frame, recognizes a policy violation, and immediately places the port into a root-inconsistent error state. This prevents rogue switches plugged into user ports from hijacking the spanning tree topology and disrupting traffic flow across the enterprise core.

Question 312

Which IPv4 address ranges are designated as private internal networks under RFC 1918?

1. 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16
2. 192.0.2.0/24, 198.51.100.0/24, and 203.0.113.0/24
3. 127.0.0.0/8 and 169.254.0.0/16
4. 224.0.0.0/4 and 240.0.0.0/4

Correct Answer: 1

Explanation:

RFC 1918 defines specific IPv4 address blocks reserved exclusively for private internal networks, allowing organizations to utilize non-routable addressing schemes internally while conserving scarce public IPv4 address space. The three designated private ranges are:

• 10.0.0.0/8 (Single Class A network spanning from 10.0.0.0 to 10.255.255.255)
• 172.16.0.0/12 (A block of 16 contiguous Class B networks spanning from 172.16.0.0 to 172.31.255.255)
• 192.168.0.0/16 (A block of 256 contiguous Class C networks spanning from 192.168.0.0 to 192.168.255.255) Packets bearing these source or destination addresses cannot be routed across the public internet; network address translation is required to reach external networks.

Question 313

Which TCP control flags are utilized during the graceful four-way connection teardown process?

1. SYN and ACK
2. FIN and ACK
3. RST and PSH
4. URG and FIN

Correct Answer: 2

Explanation:

Unlike the abrupt reset handled by the RST flag, graceful termination of a Transmission Control Protocol session requires a four-way handshake utilizing the FIN (Finish) and ACK (Acknowledgment) flags. When a communicating application finishes transmitting data, its local host sends a TCP segment with the FIN flag set. The receiving host acknowledges this termination request with an ACK segment. Once the receiving application also finishes its data transmission, it transmits its own FIN segment, which the originating host acknowledges with a final ACK. This orderly exchange ensures that both communicating endpoints successfully flush transmission buffers and release allocated socket memory without dropping in-flight data packets.

Question 314

What maximum power delivery is supported by the original IEEE 802.3af Power over Ethernet (PoE) standard per port?

1. 7.5 watts
2. 15.4 watts
3. 30.0 watts
4. 60.0 watts

Correct Answer: 2

Explanation:

The original IEEE 802.3af Power over Ethernet standard, ratified in 2003, enables enterprise switches to transmit electrical power alongside digital data streams over standard twisted-pair copper Ethernet cables to power remote devices such as IP phones, wireless access points, and security cameras. The 802.3af standard specifies a maximum power delivery of 15.4 watts of DC power at the switch source port (delivering approximately 12.95 watts of usable power at the powered device after accounting for cable resistance losses over 100 meters). For higher-power equipment such as pan-tilt-zoom cameras and multi-radio access points, the subsequent IEEE 802.3at (PoE+) standard increased power delivery capabilities up to 30.0 watts per port.

Question 315

How does configuring a floating static route provide high-availability backup across WAN links?

1. By setting a static route metric lower than any dynamic routing protocol metric.
2. By assigning an administrative distance higher than the primary dynamic routing protocol, ensuring it remains inactive until the primary path fails.
3. By automatically encrypting all backup packet payloads using IPsec.
4. By balancing traffic equally across primary and secondary interfaces simultaneously.

Correct Answer: 2

Explanation:

A floating static route is a specialized static route configured with an artificially inflated administrative distance that exceeds the administrative distance of primary dynamic routing protocols operating on the router. For example, if an enterprise router learns primary paths via EIGRP (administrative distance 90), an administrator can configure a static backup route pointing across a secondary backup WAN link with an administrative distance of 95. Because the router always prefers routes with lower administrative distances, the floating static route remains hidden from the active routing table while the EIGRP path is operational. If the primary WAN link fails and the EIGRP route is withdrawn from memory, the floating static route’s administrative distance becomes active, instantly installing the backup path into the routing table and maintaining business continuity.

Question 316

What primary security enhancement does SNMPv3 introduce compared to legacy SNMPv1 and SNMPv2c protocols?

1. Operating exclusively over TCP instead of UDP.
2. Providing robust message authentication, data integrity checks, and cryptographic encryption.
3. Eliminating the need for community strings entirely in favor of static MAC filtering.
4. Restricting polling capabilities to Layer 2 switch interfaces.

Correct Answer: 2

Explanation:

Simple Network Management Protocol versions 1 and 2c transmitted all management telemetry, configuration variables, and community strings in plain text across the network, making them vulnerable to packet sniffing and unauthorized modification attacks. SNMPv3 introduced a robust security architecture that addresses these vulnerabilities by incorporating three critical features: message integrity (ensuring packets are not altered in transit), authentication (verifying the identity of the querying management station), and cryptographic encryption (utilizing protocols like DES or AES to encrypt payload data against eavesdropping). These mechanisms transform SNMP into a secure enterprise management protocol suitable for mission-critical network infrastructures.

Question 317

What is the purpose of LLDP-MED (Media Endpoint Discovery) extensions in enterprise network environments?

1. Automatically configuring VLAN assignments, power requirements, and network policies specifically for VoIP IP phones.
2. Encrypting wireless data frames against unauthorized eavesdropping.
3. Translating private internal IPv4 addresses into public routable addresses.
4. Balancing OSPF routing metric costs across multi-access broadcast links.

Correct Answer: 1

Explanation:

Link Layer Discovery Protocol – Media Endpoint Discovery is an extension of the standard LLDP protocol designed specifically to support IP telephony and voice-over-IP endpoints. LLDP-MED enables advanced automated provisioning between enterprise switches and connected network devices—such as IP phones, video conferencing endpoints, and environmental sensors. Through LLDP-MED exchanges, switches can dynamically advertise voice VLAN voice-tagging parameters, deliver precise Power over Ethernet power management requirements to prevent oversubscription, and verify network connectivity policies, simplifying deployment and management in converged enterprise networks.

Question 318

How do IPv6 hosts generate their interface ID autonomously during Stateless Address Autoconfiguration (SLAAC)?

1. By requesting a dynamic IP lease from a central DHCPv4 server.
2. By utilizing the EUI-64 format derived from the physical MAC address or generating a cryptographically secure random interface identifier.
3. By executing Address Resolution Protocol broadcast queries across the local link.
4. By manual static entry configured by a network administrator.

Correct Answer: 2

Explanation:

Stateless Address Autoconfiguration allows an IPv6 host to configure a globally unique unicast address without requiring manual configuration or stateful DHCPv6 servers. When an interface initializes, it listens for ICMPv6 Router Advertisement messages broadcast by local routers, which supply the 64-bit network prefix. The host then combines this received prefix with its own generated 64-bit interface identifier to form a complete 128-bit IPv6 address. This interface ID is traditionally generated using the EUI-64 standard—which inserts ff:fe into the center of the device’s 48-bit MAC address and flips the universal/local bit—or via privacy extensions utilizing randomly generated interface identifiers to protect device tracking across the internet.

Question 319

What is the function of the configuration register value 0x2142 when booted on a Cisco router during password recovery?

1. Booting the normal operating system image from flash memory using the startup configuration file.
2. Bypassing the NVRAM startup configuration file to allow administrative password reset.
3. Erasing all flash memory contents completely.
4. Initializing the ROM monitor (ROMmon) emergency recovery interface.

Correct Answer: 2

Explanation:

The Cisco configuration register is a 16-bit software register stored in non-volatile random-access memory that determines how a router behaves during the boot sequence. Under normal operational conditions, the configuration register is set to 0x2102, instructing the router to load the Cisco IOS image from flash and load the saved startup configuration file from NVRAM into active RAM. During administrative password recovery procedures, a technician interrupts the boot sequence to enter ROMmon mode and modifies the configuration register to 0x2142. This specific hexadecimal value instructs the router to boot up while completely bypassing the startup configuration file, allowing the administrator to access the CLI without entering a password, copy the startup configuration into running memory, update the administrative credentials, and save the settings.

Question 320

Which OSI layer is primarily responsible for establishing, managing, and terminating communication sessions between cooperating applications?

1. Transport Layer
2. Session Layer
3. Presentation Layer
4. Application Layer

Correct Answer: 2

Explanation:

The Session layer, which is Layer 5 of the OSI reference model, is responsible for establishing, maintaining, coordinating, and terminating communication sessions between interacting software applications running on different network hosts. It handles session checkpoints, graceful connection recovery, dialog control (determining whether communication is half-duplex or full-duplex), and synchronization services. While the transport layer manages end-to-end reliability and flow control of data segments, the session layer focuses on managing logical application connections and dialogues, ensuring smooth data exchange between software processes.