If Domains One through Three are about understanding the principles and design of cybersecurity, then Domain Four is about the actual day-to-day work that keeps systems secure. This is where cybersecurity gets real. Welcome to Security Operations.

Domain Four is the largest domain on the Security Plus exam. It makes up 28 percent of the test—that’s nearly one-third of the total questions. That alone tells you how important this material is, both for the exam and for your career. Whether you want to work in a Security Operations Center, manage a network, or help an organization stay secure over time, this is the knowledge you need.

Security operations is all about what happens after systems are built and deployed. It’s the constant, ongoing effort to monitor, maintain, and protect information systems against threats that evolve by the day. It’s the stuff that never stops—patching, logging, monitoring, responding to alerts, managing identities, and maintaining secure configurations.