Open port
Course: AP® Cybersecurity Shows up in: Unit 4: Securing Devices
A network port where a service is listening for connections. Every open port is a possible way in, so unneeded ones should be closed.
Appears in the course and exam description (CED): 4.1.C.5
Why it matters in Unit 4
Each listening service is a door an adversary can try. Closing unneeded ports and services shrinks what they can reach.
Example
A laptop has port 3389 open for remote desktop although no one uses it; a host-based firewall rule blocks it.
Learn it properly, with a checkpoint 4.1 Device Vulnerabilities and Attacks