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.

Content filtering on SRX devices inspects and controls specific file types transferred across certain application protocols:

SMTP (Option A):Supported. Content filtering can block specific file attachments in emails.

HTTP (Option D):Supported. Content filtering can block downloads of specific file types over web traffic.

SNMP (Option B):Not supported; SNMP is a management protocol, not a content delivery protocol.

TFTP (Option C):Not supported by content filtering.

Correct Protocols:SMTP and HTTP

Inbound Flow (before NAT):Source =10.20.30.40(internal private IP)Destination =203.0.113.1(public DNS server)

Outbound Flow (after NAT):Source =192.0.2.1(translated IP)Destination =203.0.113.1(unchanged)

Analysis:

Thesource IP (10.20.30.40)was translated to192.0.2.1. This indicatesSource NATwas applied →Option B is correct.

Thedestination IP changedbetween the inbound and outbound view. Inbound it was203.0.113.1, and outbound it is still203.0.113.1in appearance, but notice the reversal: the session entry shows it as the outbound "source" side. This confirmsDestination NAT translation has occurredfor return flow consistency →Option D is correct.

Option A:Incorrect. The original source IP was indeed translated.

Option C:Incorrect. The destination IP did change in the flow processing.

Correct Statements:

The original source IP address was translated to a new source IP address.

The original destination IP address was translated to a new destination IP address.

On SRX Series Firewalls, Junos OS automatically createssystem-defined zonesthat have special functions:

Null zone (Option A):A predefined discard zone. By default, all interfaces belong to the null zone until assigned to a user-defined zone. Traffic destined to the null zone is dropped.

Junos-host zone (Option B):A predefined functional zone that allows security policies to control traffic directed to the SRX device itself (management traffic, such as SSH, HTTP, SNMP).

Management zone (Option C):There is a predefinedmanagement functional zone, but it is not called "management" as a system-defined security zone.

DMZ (Option D):A DMZ zone must be explicitly created by the administrator, it is not system-defined.

Correct Zones:null, junos-host

Static NAT:Provides a one-to-one bidirectional mapping between internal and external IP addresses. When configured, the translation automatically applies in both directions (Option A is correct). It does not use Port Address Translation (Option C is incorrect).

Destination NAT:Allows external clients to access internal resources by translating the destination address. It supportsport forwardingso specific services (e.g., HTTP on port 80) can be forwarded to an internal host (Option D is correct). It does not require equal-sized address ranges (Option B is incorrect).

Correct Characteristics:Static NAT is bidirectional, and Destination NAT supports port forwarding.

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

SSH Access (Option B):Host-inbound-traffic controls traffic destined to the SRX device itself (management/control plane). If host-inbound-traffic is not configured to allow SSH, then SSH access to the firewall is blocked.

Explicit Zone Configuration (Option D):For user-defined security zones, host-inbound-traffic must be explicitly configured to allow specific services (SSH, ICMP, SNMP, etc.).

Console Access (Option A):Console access is not controlled by host-inbound-traffic. Console access is always available directly.

Management Zone (Option C):In the management functional zone, host-inbound-traffic is implicitly allowed for management services, so this is not explicitly required.

Correct Statements:B and D

NAT rule processing on SRX devices follows a deterministic order:

Top-to-bottom order (Option C):NAT rules are always evaluated in the order they appear in the configuration, starting at the top.

First-match wins (Option B):Once a packet matches a NAT rule, processing stops.

Option A:Incorrect. Not all rules are processed; evaluation stops at the first match.

Option D:Incorrect. NAT rules are never processed bottom-to-top.

Correct Statements:NAT rule processing stops at the first match, and NAT rules are processed top-to-bottom.

Juniper SRX evaluatessecurity policiessequentially from top to bottom. Once a policy match is found, no further policies are evaluated. In this exhibit:

First Policy (FTP, deny):

Source: 172.25.11.0/24

Destination: 10.1.0.0/16

Application: FTP

Action: deny⇒Any FTP traffic from 172.25.11.0/24 to 10.1.0.0/16 isdenied.

Second Policy (SSH, permit):

Same source/destination but application = SSH

Action = permit⇒SSH traffic from 172.25.11.0/24 to 10.1.0.0/16 ispermitted.

Third Policy (HTTPS, permit):⇒HTTPS from the same source/destination ispermitted.

Fourth Policy (Ping, permit):

Source: 172.25.11.0/24 to any destination

Application: ping

Action: permit⇒ICMP echo requests (ping) from 172.25.11.0/24 to any destination arepermitted.

Fifth Policy (any → any, deny):⇒Serves as a defaultdeny allat the end.

Now checking each option:

Option A:SSH from 172.25.11.10 → 10.1.0.10 matches theSSH permit rule(second policy).✅Correct.

Option B:Ping from 172.25.11.100 → 10.1.0.10 matches theping permit rule(fourth policy). This traffic is permitted, not denied.❌Incorrect.

Option C:FTP from 10.1.0.10 → 172.25.11.100 isreverse traffic (untrust to trust). The table applies onlytrust → untrust, so this policy does not apply.❌Incorrect.

Option D:FTP from 172.25.11.11 → 10.1.0.10 matches the first policy (FTP deny rule).✅Correct.

Correct Statements:A, D

From the exhibit:

The user attempted to access https://www.wikipedia.org.

The block page indicates:

CATEGORY: NG_Reference

REASON: BY_PRE_DEFINED

The header states:“Juniper Web Filtering has been set to block this site.”

Analysis of options:

Option A:Correct. The log shows “REASON: BY_PRE_DEFINED,” which means the site was blocked because it matched apredefined categoryin the Web filtering database.

Option B:Correct. The category “NG_Reference” indicates that theNextGen (Enhanced/Cloud-based) Web Filtering typeis being used.

Option C:Incorrect. The exhibit does not provide any information about SSL proxy configuration; it only shows that the HTTPS site was blocked.

Option D:Incorrect. The block page shown is the standard Juniper default block page, not a custom message.

Correct Statements:The URL matches a predefined Web filtering category, and the NextGen Web Filtering type is being used.

When two networks use the same private IP address ranges, conflicts occur. The solution is to use address translation techniques on the SRX:

NAT (Network Address Translation):Translates private IP addresses to another IP range, enabling connectivity between overlapping private networks.

PAT (Port Address Translation):Extends NAT by allowing multiple private IPs to share one or a few public IPs using different port numbers. This is especially useful when there is a limited pool of public IP addresses.

Other options:

IDP (Option A):Intrusion Detection and Prevention, unrelated to address overlap.

BGP (Option C):A routing protocol, but it does not solve overlapping IP addressing problems.

Correct Features:NAT and PAT