Juniper JN0-232 Security, Associate (JNCIA-SEC) Exam Practice Test

Screen options are used to detect and prevent attacks such as floods, scans, and malformed packets. In some cases,false positivesmay occur, where legitimate traffic is mistakenly identified as malicious.

To address this, administrators can configure thealarm-without-dropoption (Option D). This setting generates alarms/logs for suspicious traffic without actually dropping it, allowing verification before taking further action.

Enabling all screen options (Option A) may increase false positives further.

Discarding traffic immediately (Option B) risks disrupting legitimate communication.

Increasing sensitivity (Option C) worsens the problem, since false positives would increase.

Correct Action:Use alarm-without-drop to log the traffic without dropping it.

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.

Exception traffic refers to traffic that must be sent from thePacket Forwarding Engine (PFE) to the Routing Engine (RE)for processing, such as routing protocol updates, management traffic, and control-plane destined packets.

Option B:Correct. Exception traffic is rate-limited on the internal connection between the PFE and RE to protect the Routing Engine from denial-of-service attacks.

Option A:Incorrect. Exception traffic is not handled only on the PFE; it requires RE involvement.

Option C:Incorrect. Rejected traffic by security policies is simply dropped, not classified as exception traffic.

Option D:Incorrect. Malformed packets are dropped, not considered exception traffic.

Correct Statement:Exception traffic is rate-limited between the PFE and RE.

In Junos OS, security zones are the foundation of SRX firewall policy enforcement. Logical interfaces must be assigned to zones. This enables:

Separation of traffic by zone boundaries.

Enforcement ofsecurity policiesfor traffic traversing between zones.

Control of traffic across VLANs, subnets, or functional areas (e.g., trust, untrust, DMZ).

Other options:

Zone assignment is not used to simplify interface configuration (A).

Routing protocols and updates (B) are handled by routing instances, not zones.

SNMP monitoring (D) is enabled under system or services configuration, not zones.

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.

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

Themanagement functional zoneon SRX devices is a special predefined zone with unique characteristics:

It isautomatically created(Option C) and cannot be deleted.

It is used specifically formanagement-related traffic(Option A), such as SSH, Telnet, web management (J-Web), SNMP, and other control-plane services.

It does not contain revenue (data) interfaces (Option B is incorrect). Interfaces must be explicitly configured into user-defined zones.

The management zone can be referenced in policies if inter-zone communication involving management traffic is needed (Option D is incorrect).

Correct Statements:A and C

From the exhibit:

The internal host (172.25.11.101) is located in theTrust zone.

The external address (203.0.113.199/30) is used for communication with the ISP.

The requirement is thatsessions can only be initiated from the external device(the ISP or untrust side) toward the internal host.

This requirement matches the behavior ofDestination NAT:

Destination NAT only (Option A):Maps the external/public IP (203.0.113.199) to the internal/private IP (172.25.11.101). This allows inbound connections to be translated and sent to the internal host. The internal host cannot initiate outbound sessions, since the translation only applies to inbound traffic.

Source NAT only (Option B):Used for outbound sessions from internal private IPs to the Internet. This does not meet the requirement.

Static PAT (Option C):Maps a single port of a public IP to a private IP/port. The exhibit does not indicate a port-based translation.

Static NAT and source NAT (Option D):Would provide bidirectional communication, allowing sessions to be initiated in both directions. This contradicts the requirement.

Correct NAT Type:Destination NAT only

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

The packet processing order in SRX with NAT and policies is:

Destination NAT(applies first, for inbound traffic).

Security Policy Evaluation(after destination NAT, before source NAT).

Source NAT(applies last, for outbound traffic).

Option A:Incorrect. Policies are not evaluated before destination NAT.

Option B:Correct. Security policies are evaluatedbefore source NATbut after destination NAT. So in terms of order, policies are processed prior to source NAT.

Option C:Incorrect. Policies are not evaluated before source NAT — they are evaluatedbefore source NAT is applied.

Option D:Correct. Policies are evaluatedafter destination NAT.

Correct Statements:B and D

In Junos OS, traffic is classified into three main categories:

Transit traffic:

Defined as traffic thatenters one interface and exits another interface.

It is handledentirely in the forwarding plane (Packet Forwarding Engine).

Example: User data packets moving between trust and untrust zones.

Correct →Option A.

Exception traffic:

Traffic requiring processing by theRouting Engine (control plane), such as routing updates or management traffic.

MatchesOption C/D, but that is not transit traffic.

Control traffic:

Management or routing-related, handled by the control plane.

Rate-limiting (Option B):

This applies specifically toexception trafficto protect the Routing Engine, not to transit traffic.

Correct Statement:Transit traffic is traffic that is processed solely through the forwarding plane.

The antivirus feature on SRX relies on signature definition files that must be regularly updated. To check the status of these updates, the correct operational command is:

show security utm anti-virus status(Option D). This displays details such as:

Antivirus engine status

Last update time of virus definitions

Version of the signature database

Other options:

Content-filtering statistics (Option A) shows counters for file-type filtering, not antivirus updates.

Anti-spam status (Option B) shows spam filtering engine connectivity.

Web filtering status (Option C) shows SBL/web filter server connection details.

Correct Command:show security utm anti-virus status

The SRX Series devices support third-party antivirus scanning engines such asAvira. To use the Avira antivirus engine, administrators must explicitly enable the engine and ensure that the required components are properly loaded.

Enable in configuration mode:

The Avira antivirus engine must be enabled under UTM configuration mode. This step ensures the SRX device uses the Avira scanning engine for antivirus inspection.

Example:

set security utm feature-profile anti-virus avira-engine enable

Reboot the SRX device:

A system reboot is required after enabling the Avira engine to load the Avira antivirus components into memory.

Without a reboot, the Avira engine will not become active.

Why not the others?

Restarting themgdprocess (Option A) only reloads the management daemon and does not load antivirus engines.

Enabling inoperational mode(Option B) is not supported; the configuration must be applied in configuration mode.

Therefore, the correct actions to use Avira Antivirus are:Enable the Avira engine in configuration mode (Option D) and reboot the SRX device (Option C).

From the exhibit output:

Policy Information:

Policy: https-access, action-type: permit

From zone: Trust, To zone: Untrust

Application: junos-https

IP protocol: tcp, Destination port: 443

Inactivity timeout: 1800

Sequence number: 1

Analysis:

Option A:Correct. The default inactivity timeout for flow sessions is60 seconds for TCP without activity. This policy shows aninactivity timeout of 1800 seconds, which is non-default.

Option B:Incorrect. The policy shows Sequence number: 1, which means it is thefirst policy, not the second.

Option C:Correct. The policy explicitly matches application junos-https (TCP port 443) and has an action of permit. Therefore, it allows HTTPS traffic.

Option D:Incorrect. This is clearly azone-based policy, but the question asks for two correct statements. Between the four options, the explicitly correct ones are A and C.

Correct Statements:This security policy uses a non-default inactivity timeout, and this security policy permits HTTPS traffic.

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

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

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.

Unified security policies (USPs) provide integrated application-aware controls usingAppIDand extend traditional zone-based policy enforcement.

Option A:Correct. If traffic matches a unified security policy, it is not re-evaluated by traditional security policies. Unified policies take precedence for matched flows.

Option B:Incorrect. Traditional policies rely on Layer 3/4 attributes. Unified policies go deeper by leveraging AppID, which inspects traffic up to Layer 7.

Option C:Incorrect. Traffic matching a traditional policy is unaffected by unified policy unless unified mode is explicitly configured for those flows.

Option D:Correct. Dynamic application recognition in unified policies usesLayer 7 (application-layer) inspectionvia AppID.

Correct Statements:A and D

Security Director (Option B):A Junos Space application that provides a centralized interface for managing, monitoring, and maintaining multiple SRX firewalls.

Juniper Secure Analytics (Option A):Focuses on SIEM/log analysis, not centralized firewall management.

Identity Management Service (Option C):Provides user identity integration for policy enforcement, not a management UI.

Secure Connect (Option D):A VPN client solution, not a firewall management platform.

Correct UI:Security Director