Juniper Exam JN0-231 Topic 2 Question 34 Discussion

Junos-host and null are two non-configurable zones that exist by default on an SRX Series device. Junos-host is the default zone for all internal interfaces and services, such as management and other loopback interfaces. The null zone is used to accept all traffic that is not explicitly accepted by other security policies, and is the default zone for all unclassified traffic. Both zones cannot be modified or deleted.