Which of the following impacts the availability of a web-based customer portal?

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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