The three-tier hierarchical model in network design consists of three layers: access, distribution, and core. The access layer is where devices like PCs and printers connect to the network. The distribution layer aggregates the data received from the access layer switches before it is transmitted to the core layer, which is responsible for high-speed data transfer and routing. This approach improves scalability and performance in larger networks. References: CompTIA Network+ Exam Objectives and official study guides.

A DoS (Denial of Service) attack directly targets availability, one of the core security goals (CIA triad) emphasized in Network+ (N10-009) security objectives. A web-based customer portal depends on reachable services (web servers, load balancers, DNS, upstream bandwidth). In a DoS, an attacker attempts to overwhelm the portal or its supporting infrastructure—consuming bandwidth, exhausting server resources, or saturating state tables—so legitimate users cannot connect or experience severe degradation. This is the most direct and common scenario where “availability” is impacted for a public web service.

MAC flooding aims to overflow a switch’s CAM table and can lead to traffic being broadcast out ports, which is more commonly associated with enabling sniffing or disruption within a local switched network segment—not typically the primary attack described for a web portal’s availability. ARP spoofing is a local network man-in-the-middle/redirection technique affecting integrity/confidentiality and potentially availability for local hosts, but it is not the best match for a public portal availability impact. Rogue devices can introduce risk, but the option is broad and indirect; DoS is the clearest availability-focused threat.

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Understanding End-of-Support:

End-of-Support Status: When a vendor declares a device as end-of-support, it means the device will no longer receive updates, patches, or technical support. This poses a security risk as new vulnerabilities will not be addressed.

Risks of Keeping an End-of-Support Device:

Security Vulnerabilities: Without updates, the switch becomes susceptible to new security threats.

Compliance Issues: Many regulatory frameworks require that critical infrastructure be maintained with supported and secure hardware.

Best Next Step - Replacement:

Decommission and Replace: The most secure approach is to replace the end-of-support switch with a new, supported model. This ensures the infrastructure remains secure and compliant with current standards.

Planning and Execution: Plan for the replacement by evaluating the network's needs, selecting a suitable replacement switch, and scheduling downtime for the hardware swap.

Comparison with Other Options:

Apply the Latest Patches: While helpful, this does not address future vulnerabilities since no further patches will be provided.

Ensure the Current Firmware Has No Issues: This is only a temporary measure and does not mitigate future risks.

Isolate the Switch from the Network: Isolating the switch may disrupt network operations and is not a viable long-term solution.

BGP (Border Gateway Protocol) is used for routing data between different ISPs, making it essential for the functioning of the internet. Its primary use is for exchanging routing information between autonomous systems, especially different ISPs. Preventing loops within a LAN ishandled by protocols like Spanning Tree Protocol (STP), while improving reconvergence times and sharing routes with a Layer 3 switch are functions of other protocols or internal mechanisms.

To validate routing between networks hosting Workstation A and File Server 2, follow these steps:

Review Routing Tables:

Check the routing tables of Router A, Router B, and Router C to identify any missing routes.

Identify Missing Routes:

Ensure that each router has routes to the networks on which Workstation A and File Server 2 are located.

Add Static Routes:

If a route is missing, add a static route to the relevant destination network via the correct interface.

Routing Table:

Gateway of last resort is 0.0.0.0 to network 0.0.0.0

S* 0.0.0.0/0 is directly connected, GigabitEthernet3

10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks

C 10.0.4.0/22 is directly connected, GigabitEthernet2

C 10.0.6.0/24 is directly connected, GigabitEthernet2

L 10.0.6.1/32 is directly connected, GigabitEthernet2

172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks

C 172.16.27.0/30 is directly connected, GigabitEthernet3

L 172.16.27.1/32 is directly connected, GigabitEthernet3

Routing Table:

Gateway of last resort is 0.0.0.0 to network 0.0.0.0

S* 0.0.0.0/0 is directly connected, GigabitEthernet1

10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks

C 10.0.0.0/22 is directly connected, GigabitEthernet1

L 10.0.0.1/32 is directly connected, GigabitEthernet1

172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks

C 172.16.27.4/30 is directly connected, GigabitEthernet1

L 172.16.27.5/32 is directly connected, GigabitEthernet1

Routing Table:

10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks

S 10.0.0.0/22 [1/0] via GigabitEthernet1

S 10.0.4.0/22 [1/0] via GigabitEthernet2

172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks

C 172.16.27.0/30 is directly connected, GigabitEthernet2

L 172.16.27.2/32 is directly connected, GigabitEthernet2

C 172.16.27.4/30 is directly connected, GigabitEthernet1

L 172.16.27.6/32 is directly connected, GigabitEthernet1

Install Static Route to 10.0.0.0/22 via 172.16.27.1 (assuming Router C's IP is 172.16.27.1):

Destination Prefix: 10.0.0.0

Destination Prefix Mask: 255.255.252.0

Interface: GigabitEthernet3

Install Static Route to 10.0.4.0/22 via 172.16.27.5 (assuming Router C's IP is 172.16.27.5):

Destination Prefix: 10.0.4.0

Destination Prefix Mask: 255.255.252.0

Interface: GigabitEthernet1

Install Static Route to 10.0.6.0/24 via 172.16.27.2 (assuming Router A's IP is 172.16.27.2):

Destination Prefix: 10.0.6.0

Destination Prefix Mask: 255.255.255.0

Interface: GigabitEthernet2

Install Static Route to 10.0.0.0/22 via 172.16.27.1 (assuming Router B's IP is 172.16.27.1):

Destination Prefix: 10.0.0.0

Destination Prefix Mask: 255.255.252.0

Interface: GigabitEthernet1

Summary of Static Routes:

Router A:

ip route 10.0.0.0 255.255.252.0 GigabitEthernet3

Router B:

ip route 10.0.4.0 255.255.252.0 GigabitEthernet1

Router C:

ip route 10.0.6.0 255.255.255.0 GigabitEthernet2

ip route 10.0.0.0 255.255.252.0 GigabitEthernet1

These configurations ensure that each router knows the correct paths to reach Workstation A and File Server 2, resolving the connectivity issue.

A captive portal is designed to present terms, conditions, or usage rules to users and require them to acknowledge/accept those rules before granting network or internet access. In Network+ (N10-009) security and access control concepts, captive portals are commonly associated with guest wireless or public access scenarios, where users are redirected to a web page that displays acceptable-use language and requires a click-through acceptance (and sometimes authentication). This provides a technical enforcement point: users must actively accept the rules to proceed, which supports organizational policy compliance and creates a recordable control in many implementations.

An Acceptable Use Policy (AUP) is the document that defines the rules, but by itself it does not technically force a user to acknowledge them at the time of access. NAC controls who/what can connect and can enforce posture and segmentation, but it does not inherently ensure users “accept” usage rules unless paired with a portal workflow. DNS filtering blocks or allows domain access categories (malware, adult content, etc.), which enforces browsing restrictions but does not guarantee user acceptance of rules. Therefore, the best answer to ensure users accept the rules is captive portal.

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The correct solution is a Data Center Interconnect (DCI). DCIs extend Layer 2 networks across geographically dispersed data centers, enabling seamless replication of services such as SAN storage, backup synchronization, or VM migrations. This ensures workloads and data can move between sites while maintaining the same VLANs and addressing.

A. Security Service Edge (SSE) provides cloud-delivered security functions like secure web gateways and CASB, not Layer 2 extension.

C. Infrastructure as code (IaC) automates deployment and management of network infrastructure but is unrelated to extending Layer 2 domains.

D. Zero Trust architecture is a security framework ensuring strict access control but doesn’t address network connectivity between sites.

In scenarios where backups need replication between sites, Layer 2 extension is often required so systems can communicate as if they are in the same broadcast domain. DCI is specifically designed to provide this functionality reliably and securely.

References (CompTIA Network+ N10-009):

Domain: Network Infrastructure — WAN technologies, data center interconnect, backup replication.