JN0-232 Exam Dumps - Security, Associate (JNCIA-SEC)

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

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).

Destination NAT purpose (Option C):Used to allow external hosts on the Internet to access internal/private resources (such as a web server in the DMZ). Destination NAT changes the destination IP of incoming traffic to match the internal server.

Pool-based NAT (Option D):SRX supports destination NAT pools, allowing multiple public IP addresses or ranges to be translated to internal servers.

Incorrect options:

Option A describessource NAT, not destination NAT.

Option B is incorrect because SRX does not support “interface-based” destination NAT.

Correct Statements:C and 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 troubleshooting packet handling on an SRX Series device, administrators need to understand exactly how theflow moduleis processing traffic. The most effective tool for this is theflow traceoptions feature.

Flow traceoptions:Provides detailed per-packet trace information showing each processing step within the flow module. It reveals how traffic is evaluated against session tables, NAT rules, and security policies. This is the recommended method for in-depth troubleshooting.

Why not the others?

Theflow session table(Option A) shows only active sessions and counters, not detailed step-by-step handling.

Theforwarding table(Option B) relates to routing and forwarding decisions, not flow security processing.

Firewall filters(Option D) can match and log traffic but do not display detailed flow processing steps.

Therefore, the correct method to get detailed information about flow handling is toenable flow traceoptions.