CCST-Networking Exam Dumps - Cisco CCST Questions and Answers

Understanding How Layer 2 Switches Handle Unknown MAC Addresses

Switches operate atLayer 2 (Data Link Layer)of the OSI model and maintain aMAC address table (CAM table)to forward frames efficiently.

When a switch receives a frame, itchecks its MAC address tableto see if it knows the destination MAC address.

If the destinationMAC address is not in the table(meaning the switch does not know which port leads to PC-C), the switch follows theflooding behavior.

What Happens When Switch1 Receives a Frame from PC-A to PC-C?

Switch1 checks its MAC table:

The source MAC (PC-A) is recorded in the table on portG0/1.

The destination MAC (PC-C)is not in the table.

Switch1 does not know where PC-C is:

Itfloodsthe frame out of allactive ports except the port it was received on (G0/1).

This means the frame is sent to:

Switch2 (via G0/23)

PC-B (via G0/2)

Switch2 receives the frame and follows the same process:

If Switch2 has PC-C's MAC in its table, it forwards the frame appropriately.

If not,it floodsthe frame again until PC-C replies.

Once PC-C responds, Switch1 and Switch2 learn its MAC address and update their tables.

Why Other Options Are Incorrect:

❌A. Switch1 queries Switch2 for the MAC address of PC-C.

Incorrect:Switches do not query other switches directly for MAC addresses. Instead, they rely on learning MAC addresses dynamically through frame forwarding.

❌B. Switch1 drops the frame and sends an error message back to PC-A.

Incorrect:Switchesdo not drop frames for unknown MAC addresses. Instead, theyfloodthe frames out all ports except the incoming port.

❌D. Switch1 sends an ARP request to obtain the MAC address of PC-C.

Incorrect:

ARP (Address Resolution Protocol)is only used to resolve IP addresses to MAC addresses.

Since PC-A issending a frame (Layer 2), not an IP packet (Layer 3), ARP isnot involvedhere.

Conclusion

Since Switch1does not know the destination MAC address, itfloods the frame out all active ports except the port it was received on. This is the default behavior of Layer 2 switches when they encounter anunknown MAC address.

Thus, thecorrect answer is:✔C. Switch1 floods the frame out all active ports except port G0/1.

References

Cisco CCNA 200-301 Official Guide – MAC Address Table & Frame Forwarding

RFC 894 – Standard for Ethernet Frame Forwarding

Cisco Networking Essentials – Switch Flooding Behavior

The two interfaces are administratively shut down:

False: The output does not show any "shutdown" command under the interfaces, which would indicate that they are administratively shut down. Therefore, they are likely in their default state, which is administratively up.

The two interfaces have default IP addresses assigned:

False: The output does not show any IP address configuration. In the default state, interfaces do not have IP addresses assigned unless explicitly configured.

The two interfaces can communicate over Layer 2:

True: By default, interfaces on a switch are Layer 2 interfaces capable of forwarding Ethernet frames. As there is no configuration provided that changes this, it can be assumed they can communicate over Layer 2.

Interface Status: The absence of the "shutdown" command means the interfaces are not administratively shut down.

IP Address Assignment: There is no evidence in the output that IP addresses have been assigned to the interfaces, which would typically be shown as "ip address" entries.

Layer 2 Communication: Switch interfaces in their default state operate at Layer 2, enabling them to forward Ethernet frames and participate in Layer 2 communication.

References:

Cisco IOS Interface Configuration: Cisco Interface Configuration

Understanding Cisco Switch Interfaces: Cisco Switch Interfaces

Based on the image description provided, here are the cable types matched with the appropriate connection descriptions:

Connects Switch S1 to Router R1 Gi0/0/1 interfaceCable Type: = Straight-through UTP Cable

Connects Router R2 Gi0/0/0 to Router R3 Gi0/0/0 via underground conduitCable Type: = Fiber Optic Cable

Connects Router R1 Gi0/0/0 to Router R2 Gi0/0/1Cable Type: = Crossover UTP Cable

Connects Switch S3 to Server0 network interface cardCable Type: = Straight-through UTP Cable

The choices are based on standard networking practices where:

Straight-through UTP cablesare typically used to connect a switch to a router or a network interface card.

Fiber optic cablesare ideal for long-distance, high-speed data transmission, such as connections through an underground conduit.

Crossover UTP cablesare used to connect similar devices, such as router-to-router connections.

These matches are consistent with the color-coded cables in the image: green for switch connections, yellow for router-to-router connections within the same rack, and blue for inter-rack connections. The use of these cables follows the Ethernet cabling standards.

Connects Switch S1 to Router R1 Gi0/0/1 interface:

Cable Type: Straight-through UTP Cable

Explanation: A straight-through UTP cable is typically used to connect different types of devices, such as a switch to a router.

Connects Router R2 Gi0/0/0 to Router R3 Gi0/0/0 via underground conduit:

Cable Type: Fiber Optic Cable

Explanation: Fiber optic cables are used for long-distance connections, such as those through an underground conduit between buildings.

Connects Router R1 Gi0/0/0 to Router R2 Gi0/0/1:

Cable Type: Crossover UTP Cable

Explanation: A crossover UTP cable is typically used to connect similar devices directly, such as router to router connections.

Connects Switch S3 to Server0 network interface card:

Cable Type: Straight-through UTP Cable

Explanation: A straight-through UTP cable is typically used to connect a switch to an end device, such as a server.

Straight-through UTP Cable: Used to connect different devices (e.g., switch to router, switch to server).

Crossover UTP Cable: Used to connect similar devices directly (e.g., router to router, switch to switch).

Fiber Optic Cable: Used for long-distance and high-speed connections, often between buildings or data centers.

References:

Network Cable Types and Uses: Cisco Network Cables

Understanding Ethernet Cabling: Ethernet Cable Guide

Firewall: A firewall is a network security device that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It permits or denies traffic based on IP addresses, port numbers, or applications.

Access Point: This is a device that allows wireless devices to connect to a wired network using Wi-Fi. It does not perform traffic filtering based on IP, port, or application.

VPN Gateway: This device allows for secure connections between networks over the internet, but it is not primarily used for traffic filtering based on IP, port, or application.

Intrusion Detection System (IDS): This device monitors network traffic for suspicious activity and policy violations, but it does not actively permit or deny traffic.

References:

Understanding Firewalls: Firewall Basics

The CIDR (Classless Inter-Domain Routing) notation for the subnet mask 255.255.252.0 is /22. This notation indicates that the first 22 bits of the IP address are used for network identification, and the remaining bits are used for host addresses within the network1.

References :=

•Subnet Cheat Sheet – 24 Subnet Mask, 30, 26, 27, 29, and other IP Address CIDR Network References

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•Subnet Mask to CIDR Notation: The given subnet mask is 255.255.252.0. To convert this to CIDR notation:

•Convert the subnet mask to binary: 11111111.11111111.11111100.00000000

•Count the number of consecutive 1s in the binary form: There are 22 ones.

•Therefore, the CIDR notation is /22.

References:

•Understanding Subnetting and CIDR: Cisco CIDR Guide

The command that will display the output provided, which includes capability codes, local interface details, device IDs, hold times, and platform port ID capabilities, is the show cdp neighbor command. This command is used in Cisco devices to display current information about neighboring devices detected by Cisco Discovery Protocol (CDP), which includes details such as the interface through which the neighbor is connected, the type of device, and the port ID of the device1.

References :=

•Cisco - show cdp neighbors

The provided output is from the Cisco Discovery Protocol (CDP) neighbor table. The show cdp neighbor command displays information about directly connected Cisco devices, including Device ID, Local Interface, Holdtime, Capability, Platform, and Port ID.

•A. show mac-address-table: Displays the MAC address table on the switch.

•C. show inventory: Displays information about the hardware inventory of the device.

•D. show ip interface: Displays IP interface status and configuration.

Thus, the correct answer is B. show cdp neighbor.

References :=

•Cisco CDP Neighbor Command

•Understanding CDP

To capture packets sent to and received from the URLhttps://www.companypro.net:7100/api using Wireshark, you would use the following filter options:

Protocol:tcp

Filter Type:port

Port Number:7100

This filter setup in Wireshark will display all TCP packets that are sent to or received from port 7100, which is the port specified in the URL for the API service. Since HTTPS typically uses TCP as the transport layer protocol, filtering by TCP and the specific port number will help isolate the relevant packets for troubleshooting the app’s data download issues.

cp: The app is using HTTPS, which relies on the TCP protocol for communication.

port: The specific port number used by the application, which in this case is 7100.

7100: This is the port specified in the URL (https://www.companypro.net:7100/api ).

This filter will capture all TCP traffic on port 7100, allowing you to analyze the packets related to the application's data download.

References:

Wireshark Filters: Wireshark Display Filters

The primary purpose of assigning an IP address to the management VLAN interface on a Layer 2 switch is to facilitate remote management of the switch. By configuring an IP address on the management VLAN, network administrators can access the switch’s Command Line Interface (CLI) remotely using protocols such as Telnet or Secure Shell (SSH). This allows for convenient configuration changes, monitoring, and troubleshooting without needing physical access to the switch1.

References :=

•Understanding the Management VLAN

•Cisco - VLAN Configuration Guide

•Remote Management of Switches

Assigning an IP address to the management VLAN interface (often the VLAN 1 interface by default) on a Layer 2 switch allows network administrators to remotely manage the switch using protocols such as Telnet or SSH. This IP address does not affect the switch's ability to route traffic between VLANs but provides a means to access and configure the switch through its Command Line Interface (CLI).

•A: The switch does not act as a default gateway; this is typically a function of a Layer 3 device like a router.

•B: The switch does not resolve URLs; this is typically a function of DNS servers.

•C: The switch can relay DHCP requests but does not typically provide DHCP services itself; this is usually done by a dedicated DHCP server or router.

Thus, the correct answer is D. To enable access to the CLI on the switch through Telnet or SSH.

References :=

•Cisco VLAN Management Overview

•Cisco Catalyst Switch Management

Two home office computers are connected to a switch by Ethernet cables.

Network Type: LAN (Local Area Network)

Explanation: A LAN connects devices within a limited area such as a home, office, or building, using Ethernet cables or Wi-Fi.

Three government buildings in the same city connect to a cable company over coaxial cables.

Network Type: MAN (Metropolitan Area Network)

Explanation: A MAN connects networks across a city or campus, often using fiber optic or coaxial cables.

A cell phone connects to a Bluetooth headset.

Network Type: PAN (Personal Area Network)

Explanation: A PAN connects devices within a personal workspace, typically using wireless technologies like Bluetooth.

A financial institution connects its branches through a telecommunications service provider.

Network Type: WAN (Wide Area Network)

Explanation: A WAN connects multiple LANs over long distances, often using leased lines or satellite links provided by telecommunications companies.

LAN (Local Area Network): Used for connecting devices within a small geographical area such as a single building or home.

MAN (Metropolitan Area Network): Covers a larger geographical area than a LAN, typically a city or campus.

PAN (Personal Area Network): Connects devices within the range of an individual person, such as connecting a phone to a Bluetooth headset.

WAN (Wide Area Network): Spans large geographical areas, connecting multiple LANs across cities, countries, or continents.

References:

Network Types Overview: Cisco Networking Basics

Understanding Different Network Types: Network Types Guide

Three virtual machines are connected by a virtual network in the cloud.

Model: IaaS (Infrastructure as a Service)

Explanation: IaaS provides virtualized computing resources over the internet, including virtual machines, storage, and networks.

Users access a web-based graphics design application in the cloud for a monthly fee.

Model: SaaS (Software as a Service)

Explanation: SaaS delivers software applications over the internet, typically on a subscription basis, accessible via a web browser.

A company develops applications using cloud-based resources and tools.

Model: PaaS (Platform as a Service)

Explanation: PaaS provides a platform allowing customers to develop, run, and manage applications without dealing with the infrastructure.

IaaS (Infrastructure as a Service): Provides virtualized hardware resources that customers can use to build their own computing environments.

PaaS (Platform as a Service): Offers a platform with tools and services to develop, test, and deploy applications.

SaaS (Software as a Service): Delivers fully functional applications over the internet that users can access and use without managing the underlying infrastructure.

References:

Cloud Service Models: Understanding IaaS, PaaS, SaaS

NIST Definition of Cloud Computing:NIST Cloud Computing