CyberGuard dictionary / Network Security
Denial of Service
Also known as DoS
An event or attack that prevents legitimate users from accessing a service.
In simple terms
Too much traffic or another disruption keeps ordinary users from reaching a site.
Technical explanation
A denial-of-service attack exhausts capacity or a dependency; distributed attacks use multiple sources and require different mitigation choices.
Availability can fail when requests exhaust bandwidth, application capacity, or a shared dependency. Mitigation differs for network floods, expensive application requests, and accidental traffic spikes.
Examples in practice
A website becomes unreachable when traffic from many compromised devices overwhelms its connection.
A flood of costly search requests overwhelms the site even though network bandwidth remains available. Operators rate-limit that endpoint and add capacity while investigating the source.
Why it matters
Availability planning and provider coordination can reduce disruption.
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Sources and further reading
Published 2026-10-15 · Last updated 2026-10-15 · CyberGuard editorial content. Source links provide context; they do not imply endorsement.