On a Juniper SRX Series device, the security policy lookup process follows a strict hierarchical order. For any given traffic session, the device first evaluates the zone-based policies that are specific to the source and destination zone pair. If a matching policy is found within the zone context, it is applied, and the evaluation process stops. Only if no matching zone-based policy is found does the device proceed to evaluate the global policies. This ensures that specific rules for traffic between zones take precedence over more general, global rules.

B. The most restrictive policy is applied regardless of the policy level. This is incorrect. The SRX device applies the first matching policy it encounters in its lookup sequence, not the most restrictive one.

C. A global policy is always evaluated first. This is incorrect. Global policies are evaluated only after the device has checked for and failed to find a matching zone-based policy.

D. The first policy rule is applied regardless of the policy level. This statement is imprecise. The evaluation is structured by policy level (zone-based, then global), not just the order of rules in the configuration.

Juniper Networks TechLibrary

Security Policies Overview: "For a given session

the SRX Series device checks for a matching security policy in the following order: 1. Zone-based policies: Policies that are specific to a pair of zones. 2. Global policies: Policies that apply to all zones." Juniper Networks TechLibrary - Security Policies Overview

Juniper Networks TechLibrary

Understanding Unified Security Policies: This document details the integration of various security features into a single policy structure

which adheres to the fundamental zone-then-global lookup order. Juniper Networks TechLibrary - Understanding Unified Security Policies