If the business shares or duplicates the ISP-assigned public IP address, routing instability and conflicts will occur. Pinging a public IP like 8.8.8.8 may work (since ICMP can bypass certain conflicts), but browsing websites (which requires stable sessions and return traffic) will fail intermittently.
A . If the default gateway were incorrect, no external connectivity would work at all.
B . VLAN mismatch is an internal issue, not affecting ISP routing.
C . Subnet mask misconfiguration would prevent consistent routing but usually blocks ping too.
Reference (CompTIA Network+ N10-009):

This describes aSpanning Tree Protocol (STP) loop. If STP isn't correctly configured or a redundant link is added without STP protection, it causesbroadcast storms and network outages.
* A. Unused ports disabledwould not affect the entire network.
* B. Missing default gatewayon a switch doesn't cause total network loss.
* **C. Connecting a switch to an access port can cause VLAN mismatches, but not total connectivity loss unless a loop forms.
#Reference:
CompTIA Network+ N10-009 Official Objectives: 3.6 - Explain the characteristics of network topologies and types.

IPSec (Internet Protocol Security) is the best choice for secure communication over the internet, as it provides encryption, authentication, and data integrity. It is widely used in VPNs and site-to-site secure tunnels.
Breakdown of Options:
A . DCI (Data Center Interconnect) - A general term for linking data centers, but it doesn't specify a secure tunneling protocol.
B . GRE (Generic Routing Encapsulation) - Encapsulates traffic but lacks encryption, making it less secure than IPSec.
C . VXLAN (Virtual Extensible LAN) - Used for Layer 2 network overlays, not for securing communication over the internet.
D . IPSec - ✅ Correct answer. Provides encryption, authentication, and integrity for data over the internet.
Reference:
CompTIA Network+ (N10-009) Official Study Guide - Domain 3.5: Implement secure remote access methods.
RFC 4301: Security Architecture for the Internet Protocol

Content filtering blocks access to restricted or malicious websites. When a user attempts to visit a site that violates company policies, they are redirected to a restriction page.
* This is a common security measure to prevent employees from accessing phishing or malware-infected sites.
* Content filters work by scanning URLs, keywords, or categories and blocking inappropriate or harmful content.
* Option A (DLP - Data Loss Prevention): Focuses on preventing sensitive data leaks rather than blocking web access.
* Option B (Captive portal): Used mainly in public Wi-Fi to authenticate users before granting access, not to restrict sites.
* Option D (DNS sinkholing): Redirects malicious domain requests to a safe address but is not responsible for policy-based restrictions on general content.
? Reference: CompTIA Network+ (N10-009) Official Study Guide - Section: Security Solutions

Power over Ethernet (PoE) allows devices such as cameras, access points, and VoIP phones to receive both power and data over the same Ethernet cable. If only eight out of twelve cameras turn on, the most likely issue is that the PoE switch has exceeded its power budget (total wattage capacity).
PoE Budget Limitation: PoE switches have a maximum power output, which can limit the number of devices they support simultaneously.
Voltage Check: Different PoE standards exist:
802.3af (PoE): Supplies up to 15.4W per port
802.3at (PoE+): Supplies up to 30W per port
802.3bt (PoE++): Supplies up to 60-100W per port
Power Draw Calculation: If each camera requires 15W and the switch can only provide 120W, then only 8 cameras (8 × 15W = 120W) will turn on.
Incorrect Options:
A . Ethernet Cable Type: Most PoE devices work with Cat5e and above. Cable type could be an issue, but power limitation is the more immediate concern.
C . Transceiver Compatibility: Only relevant if fiber transceivers or modules are in use, but not likely the root cause for power-related issues.
D . DHCP Addressing: DHCP issues affect network connectivity, not power delivery.
Reference:
CompTIA Network+ N10-009 Official Study Guide - Chapter on Power over Ethernet (PoE)