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Question 201. Which Cisco IOS command is used to assign an IP address to an interface?

1. ip route
2. ip address
3. ip default-gateway
4. network

Correct Answer: 2. ip address

Explanation :-

The ip address command assigns an IPv4 address and subnet mask to a Cisco interface. The command is entered from interface configuration mode, for example, ip address 192.168.1.1 255.255.255.0. The interface must also be enabled with the no shutdown command if it has been administratively disabled. ip route creates a static route, ip default-gateway configures a default gateway on certain Layer 2 switches, and network is used in various routing-protocol configurations. Therefore, ip address is the command used to configure an IPv4 address directly on an interface.

Question 202. Which protocol is responsible for preventing switching loops in a redundant Layer 2 topology?

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

Correct Answer: 3. STP

Explanation :-

Spanning Tree Protocol (STP) prevents Layer 2 switching loops when redundant paths exist between switches. Without a loop-prevention mechanism, Ethernet frames can circulate continuously, potentially causing broadcast storms, duplicate frames, and MAC address-table instability. STP calculates a loop-free logical topology and places selected redundant ports into a blocking state while maintaining them as potential backup paths. DHCP assigns network configuration, NAT translates addresses, and DNS performs name resolution. STP is therefore the protocol specifically designed to protect a switched network from Layer 2 forwarding loops.

Question 203. Which IPv4 address range is reserved for automatic private IP addressing when a DHCP server is unavailable?

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

Correct Answer: 1. 169.254.0.0/16

Explanation :-

The IPv4 range 169.254.0.0/16 is reserved for link-local addressing and is commonly associated with Automatic Private IP Addressing (APIPA) when a host cannot obtain an IPv4 address from DHCP. A host may automatically assign itself an address from this range, allowing limited local-link communication. The ranges 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 are RFC 1918 private address ranges and are normally assigned through manual configuration or DHCP. Link-local addresses are not intended to provide normal routed communication across an IP network.

Question 204. Which command displays the interfaces and their associated IPv4 addresses in a concise summary?

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

Correct Answer: 4. show ip interface brief

Explanation :-

The show ip interface brief command provides a concise summary of Cisco interfaces, including their IPv4 addresses and operational status. It is especially useful for quickly identifying interfaces that are up, down, or administratively disabled. The show interfaces command provides much more detailed interface statistics, while show ip route displays routing information. show version provides device and IOS information. Because it combines interface names, IP addresses, and status information in a compact format, show ip interface brief is one of the most frequently used commands during initial network troubleshooting.

Question 205. What is the main purpose of Network Address Translation (NAT)?

1. Prevent Layer 2 loops
2. Translate addresses between different IP address spaces
3. Discover neighboring Cisco devices
4. Synchronize network clocks

Correct Answer: 2. Translate addresses between different IP address spaces

Explanation :-

Network Address Translation (NAT) translates IP addresses between different address spaces. A common use is translating private IPv4 addresses used inside an organization into public IPv4 addresses for Internet communication. NAT can operate through several methods, including static NAT, dynamic NAT, and Port Address Translation (PAT). STP handles Layer 2 loop prevention, CDP discovers Cisco neighbors, and NTP synchronizes clocks. NAT is particularly important in IPv4 networks because private addresses are not directly routable on the public Internet and public IPv4 addresses are limited.

Question 206. Which command saves the running configuration to the startup configuration?

1. copy startup-config running-config
2. copy flash startup-config
3. copy running-config startup-config
4. write erase

Correct Answer: 3. copy running-config startup-config

Explanation :-

The copy running-config startup-config command saves the active configuration from RAM to the startup configuration in NVRAM. This ensures that configuration changes are preserved when the Cisco device is restarted. The copy startup-config running-config command performs the reverse operation by loading the saved configuration into the active configuration. write erase removes the startup configuration rather than saving it. Saving configurations is an important administrative task because changes that exist only in the running configuration can be lost after a reload or power interruption.

Question 207. Which IPv6 prefix is associated with unique local unicast addresses?

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

Correct Answer: 1. FC00::/7

Explanation :-

The IPv6 prefix FC00::/7 identifies the unique local address range. Unique local addresses are intended for private internal communication and are not globally routable on the public Internet. They are conceptually similar to private IPv4 addressing, although their addressing rules and design differ. FE80::/10 is used for link-local addresses, FF00::/8 is reserved for multicast, and 2000::/3 identifies global unicast addresses. Understanding IPv6 address ranges helps administrators distinguish between addresses intended for local communication, global routing, multicast delivery, and neighbor operations.

Question 208. Which command can be used to view the MAC addresses learned by a Cisco switch?

1. show ip interface brief
2. show mac address-table
3. show ipv6 route
4. show startup-config

Correct Answer: 2. show mac address-table

Explanation :-

The show mac address-table command displays MAC addresses learned by a Cisco switch and the associated VLAN and interface information. Switches dynamically learn source MAC addresses from incoming Ethernet frames and use the resulting table to make forwarding decisions. show ip interface brief provides interface and IPv4 information, show ipv6 route displays the IPv6 routing table, and show startup-config displays the saved configuration. When troubleshooting Layer 2 forwarding or determining which switch port is associated with a particular MAC address, the MAC address table is a key source of information.

Question 209. Which protocol provides secure remote terminal access using TCP port 22?

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

Correct Answer: 3. SSH

Explanation :-

Secure Shell (SSH) provides encrypted remote terminal access and normally uses TCP port 22. It is widely used to securely manage Cisco network devices because it protects authentication credentials and session traffic through encryption. Telnet can also provide remote CLI access, but it does not provide the same encryption and normally uses TCP port 23. FTP and TFTP are file-transfer protocols rather than secure interactive terminal protocols. SSH is therefore the standard protocol for secure remote command-line management of Cisco routers and switches.

Question 210. Which command displays detailed information about the current status and statistics of an interface?

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

Correct Answer: 1. show interfaces

Explanation :-

The show interfaces command displays detailed information about Cisco interfaces, including operational status, line protocol status, bandwidth, packet counters, errors, encapsulation, duplex information, and other statistics. This makes it valuable for diagnosing physical and data-link problems. show vlan brief provides VLAN information, show ip route displays routing information, and show cdp neighbors displays directly connected Cisco devices. When an interface is experiencing packet errors, connectivity problems, or unexpected status changes, show interfaces can provide detailed information needed for troubleshooting.

Question 211. Which type of Ethernet frame is sent to all devices within the same Layer 2 broadcast domain?

1. Unicast
2. Anycast
3. Broadcast
4. Point-to-point

Correct Answer: 3. Broadcast

Explanation :-

An Ethernet broadcast frame is intended for all devices within the same Layer 2 broadcast domain. The destination MAC address for an Ethernet broadcast is FF:FF:FF:FF:FF:FF. Switches normally flood broadcast frames out all appropriate ports within the same VLAN except the port on which the frame arrived. Routers do not normally forward Layer 2 broadcasts between interfaces. Unicast traffic is directed to a specific destination, while anycast is primarily associated with IP addressing rather than Ethernet broadcast delivery. Broadcast behavior is therefore an important concept in understanding VLANs and Layer 2 networks.

Question 212. Which protocol is used to resolve an IPv4 address to a MAC address?

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

Correct Answer: 2. ARP

Explanation :-

Address Resolution Protocol (ARP) resolves an IPv4 address to a corresponding MAC address on a local network. When a device needs to send an IPv4 packet to a host on the local subnet, it can use ARP to determine the destination’s Layer 2 address. The resulting mapping is stored in the ARP cache for later use. DNS resolves domain names to IP addresses, NTP synchronizes clocks, and SNMP supports network monitoring and management. IPv6 uses Neighbor Discovery Protocol rather than ARP for address-resolution functions.

Question 213. Which command removes an IP address from a Cisco interface configuration?

1. no ip address
2. shutdown
3. clear ip route
4. no shutdown

Correct Answer: 1. no ip address

Explanation :-

The no ip address command removes the configured IPv4 address from a Cisco interface. It is entered from interface configuration mode. The shutdown command administratively disables an interface but does not specifically remove its configured IP address. no shutdown enables an administratively disabled interface, while clear ip route is associated with clearing routing information rather than modifying an interface address. Cisco IOS uses the no form of many configuration commands to remove or negate previously configured settings.

Question 214. Which routing protocol is classified as a distance-vector protocol and uses hop count as its metric?

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

Correct Answer: 2. RIP

Explanation :-

Routing Information Protocol (RIP) is a distance-vector routing protocol that uses hop count as its routing metric. Each router adds one hop when advertising a route through itself. RIP considers a route with 16 hops unreachable, which limits its scalability for large networks. OSPF is a link-state routing protocol, BGP is a path-vector protocol, and STP is a Layer 2 loop-prevention protocol rather than an IP routing protocol. RIP remains important for understanding fundamental distance-vector routing concepts even though modern networks often use more scalable routing protocols.

Question 215. Which feature allows a switch to aggregate several physical links into a single logical connection?

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

Correct Answer: 3. EtherChannel

Explanation :-

EtherChannel aggregates multiple physical Ethernet interfaces into one logical connection. The resulting logical interface can provide increased bandwidth and redundancy while simplifying the way protocols such as STP view the bundled links. EtherChannel can be implemented using negotiation protocols such as LACP or PAgP, depending on the configuration and platform. DHCP snooping protects against rogue DHCP servers, port security controls MAC addresses on switch ports, and router-on-a-stick provides inter-VLAN routing through a router trunk connection. EtherChannel specifically addresses link aggregation and redundancy.

Question 216. Which IPv6 address type is automatically configured on an interface for local-link communication?

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

Correct Answer: 4. Link-local

Explanation :-

IPv6 interfaces use link-local addresses for communication with neighboring devices on the local link. Link-local addresses are associated with the FE80::/10 prefix and are not intended to be routed across different links. They are important for Neighbor Discovery Protocol and many IPv6 routing operations. Global unicast addresses are used for broader routed communication, unique local addresses provide private IPv6 addressing, and multicast addresses identify groups of interfaces. Link-local addressing is a fundamental part of IPv6 and allows local communication even when global addressing is not configured.

Question 217. Which command displays information about the Cisco IOS version currently running on a device?

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

Correct Answer: 1. show version

Explanation :-

The show version command displays information about the Cisco IOS software version and the device’s hardware and system environment. Output can include the IOS release, platform model, memory information, uptime, configuration register, and other details. show flash focuses on files stored in flash memory, show running-config displays the active configuration, and show history displays previously entered commands where supported. Administrators frequently use show version during troubleshooting, software verification, and device inventory because it provides a broad overview of the running platform and software.

Question 218. What is the main purpose of a subnetting scheme?

1. Encrypt IP packets
2. Divide an IP network into smaller logical networks
3. Replace MAC addresses
4. Disable routing between networks

Correct Answer: 2. Divide an IP network into smaller logical networks

Explanation :-

Subnetting divides a larger IP network into smaller logical networks called subnets. This allows organizations to use address space more efficiently, reduce broadcast-domain sizes, and organize hosts according to network requirements. A subnet mask or prefix length determines which portion of an IP address identifies the subnet and which portion identifies hosts. Subnetting does not encrypt packets or replace MAC addresses. Routing can be used to provide communication between separate subnets. Proper subnetting is an important part of scalable IPv4 network design and address management.

Question 219. Which protocol is commonly used to synchronize time between network devices and a centralized time source?

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

Correct Answer: 3. NTP

Explanation :-

Network Time Protocol (NTP) synchronizes the clocks of network devices with a trusted time source. Consistent time is important for accurate logging, troubleshooting, security event correlation, and some authentication processes. Cisco devices can be configured to use an NTP server so that their clocks remain synchronized. FTP provides file transfer, ARP resolves IPv4 addresses to MAC addresses, and ICMP provides control and diagnostic messages. NTP therefore provides the time-synchronization function required when multiple network devices need consistent timestamps.

Question 220. Which command can be used to test whether a destination is reachable using ICMP Echo messages?

1. traceroute
2. ping
3. show ip route
4. telnet

Correct Answer: 2. ping

Explanation :-

The ping command uses ICMP Echo Request and Echo Reply messages to test basic IP connectivity between a source and destination. It can provide information about whether the destination responds and can show round-trip time and packet loss. traceroute is used to discover the Layer 3 path toward a destination, while show ip route displays the routing table. Telnet can be used to test TCP connectivity to a particular service, but it is not the standard ICMP reachability test. Therefore, ping is the appropriate command for basic ICMP connectivity verification.