Pass the Juniper Associate JNCIA-SEC JN0-232 Questions and answers with CertsForce

Default assignment:All logical interfaces are placed in thenull zone by defaultuntil explicitly assigned to a user-defined security zone (Option A is correct).

Removal from null zone:Once an interface is assigned to a security zone, it is removed from the null zone (Option D is correct).

No traffic acceptance:The null zone is a discard zone; it cannot be configured to accept any traffic (Option C is incorrect).

Policy behavior:Traffic rejected by a security policy is dropped according to the policy action. It is not forwarded to the null zone for logging (Option B is incorrect).

Correct Statements:A and D

Security policies in Junos OS match traffic based on specific criteria:

Source and destination addresses(Option B).

Application(Option D), which may be defined as services (e.g., tcp/80) or recognized through AppID.

Other options:

MAC addresses(Option A) are not used in policy matching; policies operate at Layer 3/4.

Interface name(Option C) is used in firewall filters, not in security policy definitions.

Correct Criteria:Source address and Applications

License Requirement (Option B):NextGen Web Filtering (NGWF) is a licensed feature on SRX devices. Without a license, the service cannot operate.

Local vs. Cloud Lists (Option C):NGWF checkslocal block/allow lists first. If the URL does not match locally, the request is then checked against the Juniper cloud database.

Option A:Incorrect, since the cloud is only consulted if the URL is not in the local list.

Option D:Incorrect, as NGWF requires a valid subscription/license.

Correct Statements:NGWF requires a license, and it checks local lists before cloud lookup.

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.

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.

By default, SRX 300 Series Firewalls come with predefined security policies:

Trust-to-Untrust (Option B):A default policy exists to permit all traffic from thetrust zone to the untrust zone.

Trust-to-Trust (Option D):Intra-zone traffic is permitted by default; hence, a trust-to-trust policy is installed automatically.

Untrust-to-Trust (Option A):Not allowed by default, since external traffic must be explicitly permitted by an administrator.

Management-to-Trust (Option C):No such default policy exists.

Correct Policies:Trust-to-Untrust and Trust-to-Trust

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.

Transit traffic is defined as traffic that passesthroughthe SRX (not destined to the Routing Engine). To capture transit traffic:

Sampling and port mirroring (Option D)are the correct supported methods for capturing or exporting transit traffic. Sampling allows captured packets to be sent to a file or collector, while port mirroring sends a copy to a monitoring interface.

Option A:Firewall filters on an egress interface cannot directly capture packets; they can only count, accept, discard, or sample. Sampling itself is separate.

Option B:Loopback interface (lo0) is for control-plane traffic, not transit traffic.

Option C:tcpdump is not supported on SRX as a tool for capturing transit packets; the operational command monitor traffic interface is used, but sampling/port mirroring is the recommended scalable approach.

Correct Method:Sampling and port mirroring

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