Functional zones are special, system-defined zones in Junos OS for traffic destined for or originating from the device itself, not for transit traffic passing through it. The management functional zone is specifically created for out-of-band management access. Because functional zones are not intended for transit traffic, they cannot be referenced in security policies that control traffic between standard security zones. Junos OS automatically creates functional zones; they are not user-defined.

A. Functional zones must have a user-defined name.

Incorrect. Functional zones are system-defined with reserved names (e.g., management, null) and are not created or named by the user.

C. Multiple types of functional zones can be defined by the user.

Incorrect. Users define security zones by assigning interfaces to them; functional zones are built-in and cannot be created by the user.

1. Juniper Networks TechLibrary

"Understanding Functional Zones": "Junos OS defines two functional zones: the management zone and the null zone. You do not configure functional zones; Junos OS automatically creates them... The management zone is a built-in zone that is used for out-of-band management of the device."

URL: https://www.juniper.net/documentation/us/en/software/junos/security-policies/topics/concept/security-zone-functional-understanding.html

2. Juniper Networks TechLibrary

"Understanding Security Zones": "A zone cannot be a functional zone. Functional zones cannot be used in security policies to control transit traffic."

URL: https://www.juniper.net/documentation/us/en/software/junos/security-policies/topics/concept/security-zone-understanding.html