JN0-232 Exam Dumps - Juniper Associate JNCIA-SEC Questions and Answers

Functional zones(e.g., junos-host, management, null) are not used for forwarding transit traffic. They are used to manage traffic destined to or from the SRX device itself.

Option A:Correct. If traffic enters through a functional zone interface, it is meant for the SRX, not for transit, so it cannot exit another interface.

Option D:Correct. Transit interfaces handle forwarding traffic, but they cannot send that traffic out through a functional zone interface.

Option B and C:Incorrect, because functional zones are strictly control-plane, not transit forwarding zones.

Correct Statements:A and D

Juniper SRX evaluatessecurity policies in order, top to bottom. The first matching policy determines the action, and no further policies are evaluated. This behavior can lead toshadowed policiesif later policies match the same conditions as earlier ones.

From the exhibit:

Policy1:Matches application junos-http and permits traffic.

Policy2:Matches application junos-https and permits traffic.

Policy3:Matches application junos-http again, but denies traffic.

Sincepolicy1already matches all HTTP traffic and permits it, traffic never reachespolicy3. This makespolicy3 shadowedbecause it has the same match condition as policy1 but is evaluated later in the list.

Other options:

Policy1 is not shadowed because it is evaluated first.

Policy2 is independent (application = HTTPS) and therefore unaffected.

Only policy3 is shadowed by policy1.

Correct Statement:Policy3 will be shadowed because it matches the same application as policy1.

Exception traffic is traffic that must be sent from the Packet Forwarding Engine (PFE) to the Routing Engine (RE) for processing, such as routing protocol updates, management traffic, or other control-plane packets. Because the RE is a limited and critical resource, Junos OS implementsrate limiting on exception traffic.

The purpose is toprevent denial-of-service (DoS) attacks on the Routing Engineby controlling the amount of traffic directed to it.

This ensures the RE continues to process control-plane operations reliably, even under potential attack or heavy traffic conditions.

Rate limiting does not enhance forwarding plane performance (Option A), simplify interface configuration (Option B), or manage routing protocols directly (Option D).

Option B:Correct. Interfaces in the same security zone must belong to the same routing instance; zones cannot span multiple routing instances.

Option D:Correct. A security zone can contain multiple interfaces, allowing grouping of similar trust levels (e.g., multiple LAN subnets in a trust zone).

Option A:Incorrect. An interface can belong to only one zone at a time.

Option C:Incorrect. Interfaces within the same zone cannot be split across routing instances.

Correct Statements:Interfaces in the same zone must share the same routing instance, and a zone can contain multiple interfaces.

In Juniper SRX flow-based packet processing, theflow moduleis responsible for security functions such as screening, session management, NAT, and policy enforcement. The processing order is critical:

Screens are applied before any session lookup.This ensures that packets are inspected for anomalies, floods, or protocol violations before consuming resources for session management. Examples of these screens include TCP SYN flood protection, ICMP flood protection, and port scanning protection.

After screening, thesession lookupoccurs. At this point, the firewall checks whether the packet belongs to an existing session in the session table. If a matching session is found, the packet bypasses policy evaluation and is forwarded according to the session state.

If no existing session is found, the packet continues throughroute lookup, NAT processing, and security policy evaluationbefore a new session is created.

Thus,screening occurs before the session lookup, protecting the system early in the flow process. This design ensures efficiency by dropping malicious or malformed traffic before allocating session resources.

From the exhibit configuration:

[edit security policies from-zone Trust to-zone Trust]

policy allow-all {

match {

source-address any;

destination-address any;

application any;

}

then {

permit;

}

}

Thefrom-zoneandto-zoneare both set toTrust → Trust.

This means the policy is governing trafficwithin the same zone.

Policies within the same zone are calledintra-zone policies.

Analysis of options:

Global policy (A):Applied universally across zones, not zone-specific. Not the case here.

Inter-zone policy (B):Applies between twodifferentzones (e.g., Trust → Untrust). Not the case here since both zones are Trust.

Intra-zone policy (C):Correct. Applies to traffic within the same zone (Trust → Trust).

Default policy (D):The implicit deny-all policy that applies when no policy matches. Not shown in this exhibit.

Correct Policy Type:Intra-zone policy

Global security policies extend the flexibility of policy enforcement across the SRX. They are not tied to specific source and destination zones:

From-zone and to-zone contexts are not required(Option A). Global policies apply across all zones unless restricted by match conditions.

Global security policies do not require specific zone contexts(Option B is incorrect).

Global policies areprocessed after zone-based policies, not before. This means that zone-based security policies take precedence (Option C is incorrect).

Administrators can configure bothzone-based security policies and global security policies at the same timeon the same device (Option D is correct).

This allows flexible designs where specific policies can be enforced by zone, while general policies can be applied globally without duplicating rules across multiple zones.

Intra-zone traffic:On SRX devices, traffic between interfaces in the same security zone is allowedwithout requiring a security policy(Option C is correct). Policies are only evaluated for inter-zone traffic.

Junos-host functional zone:This zone is a predefined functional zone that allows administrators to apply policies controlling access to the SRX firewall itself, such as SSH, HTTP, or SNMP traffic (Option D is correct).

Null zone:This zone is a predefined discard zone. Interfaces placed in the null zone drop all traffic. It does not allow policy logging of dropped control plane traffic (Option A is incorrect).

Management functional zone:This is used to define management interfaces, not the “functional zone” as stated in Option B (incorrect wording).

Correct Statements:C and D

When a packet enters an SRX interface, aroute lookupis performed:

It determines theegress interface(Option B) by checking the destination IP against the routing table.

Once the egress interface is known, its associatedegress security zone(Option D) is also determined.

Theingress interface (Option A)is already known when the packet arrives, so the route lookup does not determine it.

DNS name (Option C):DNS is unrelated to routing lookups.

Correct Results:egress interface, egress security zone