Which term refers to a security control configuration that treats a failure as a green light, allowing access?

Which term refers to a security control configuration that treats a failure as a green light, allowing access?

• A. Fail-closed
• B. Fail-open
• C. Layer 4 firewall
• D. State table

Answer: (B)

Fail-open is the term for a security control configuration that defaults to permitting access when the control fails. It’s like a green light: if the device or rule can’t evaluate a request due to a fault, the system allows the traffic or access to proceed rather than blocking it. This design emphasizes availability—users aren’t locked out because of a fault—but it trades some security, since an outage could temporarily let unauthorized access slip through. The other options don’t describe this failure behavior: a Layer 4 firewall is about filtering by transport layer information, not what happens on failure, and a state table is a mechanism for tracking connections, not a failure-default policy.

Fail-open is the term for a security control configuration that defaults to permitting access when the control fails. It’s like a green light: if the device or rule can’t evaluate a request due to a fault, the system allows the traffic or access to proceed rather than blocking it. This design emphasizes availability—users aren’t locked out because of a fault—but it trades some security, since an outage could temporarily let unauthorized access slip through. The other options don’t describe this failure behavior: a Layer 4 firewall is about filtering by transport layer information, not what happens on failure, and a state table is a mechanism for tracking connections, not a failure-default policy.