A policy scheduler in Junos OS defines the specific time frame during which a security policy is active and evaluated. This is its fundamental purpose. Schedulers are configured based on time, not dynamic network conditions. A common and valid configuration is to define a schedule that repeats on a daily basis, for example, during business hours. When a scheduler is applied to a policy, that policy will only permit or deny traffic during the specified active times.

A: The policy-rematch feature is independent. While useful when a scheduler changes a policy's state, a scheduler can be applied to a policy without policy-rematch being configured.

B: Schedulers are strictly time-based (e.g., time of day, day of week). They are not activated by dynamic conditions such as traffic flow volume.

1. Juniper Networks TechLibrary

Junos OS Security Configuration Guide

"Understanding Security Policy Schedulers."

Quote: "A scheduler defines when a security policy is active... You can configure a scheduler to run daily

weekly

or on a specific date and time."

Relevance: This directly supports options D (defines when a policy is active) and C (can be configured to run daily). It also implicitly refutes option B by defining schedulers as time-based

not condition-based.

2. Juniper Networks TechLibrary

Junos OS Security Configuration Guide

"Example: Configuring a Security Policy Scheduler."

Reference: The configuration example shows setting a scheduler for start-date 2019-01-01.09:00 stop-date 2019-01-01.17:00

which is a daily time frame.

Relevance: This provides a concrete example that validates option C

showing how a daily schedule is configured.

3. Juniper Networks TechLibrary

Junos OS Security Configuration Guide

"Understanding Session Rematch for Security Policies."

Quote: "When you modify a security policy

you can use the policy-rematch option to apply the changes to existing sessions."

Relevance: This shows that policy-rematch is a separate feature for handling policy changes

not a prerequisite for using a scheduler

thus refuting option A.