Free Practice Questions for the Juniper JNCIS-SEC JN0-336 Exam (2026 Updated)

The correct answer is A. fab. In SRX Series chassis clustering, the fabric interface, shown as fab0/fab1, is the data-plane HA link used between cluster nodes. Juniper states that SRX chassis clusters use the fabric interface for session synchronization and traffic forwarding, and that the fabric link synchronizes dynamic runtime state, including session-state objects created by NAT, ALG, authentication, and IPsec processing. This is what enables stateful failover and session continuity when traffic processing moves between nodes.

Option B, fxp0, is wrong because fxp0 is the out-of-band management interface, not the chassis-cluster synchronization path. Option C, fxp1, is tempting but wrong for this question: fxp1 is the control-link interface used for control-plane cluster functions such as heartbeats and cluster control communication, not the main session-state synchronization path. Option D, swfab, is not the standard SRX chassis-cluster fabric interface name used for this function. Juniper’s clustering configuration examples specifically define fab0 and fab1 as the interfaces used for the fabric connection and data-plane RTO/session synchronization.

The correct answers are C and D. The cSRX is Juniper’s containerized SRX firewall, intended for lightweight virtual and container environments where rapid deployment and high density matter. Juniper’s cSRX documentation lists supported security capabilities including basic firewall policy, NAT, Intrusion Detection and Prevention, content security/UTM functions, ATP Cloud, SSL Proxy, AppID, AppFW, and AppTrack. That supports option C, because cSRX provides SRX security services in a containerized footprint rather than requiring a full VM-based firewall appliance.

Option D is also correct because Juniper identifies the cSRX’s small footprint and minimum resource reservation requirements as key benefits; it is designed to scale more densely than VM-based firewall options. Juniper’s Day One cSRX guide specifically identifies faster deployment, a small footprint, and reduced resource consumption as major benefits. Option A is not the best answer for this exam item because the question asks for cSRX deployment benefits, not merely forwarding-mode support. Option B is wrong because the tested cSRX advantage is not a default three-zone configuration. Reference topics: cSRX container firewall, virtual SRX deployment, firewall/NAT/IPS/UTM services, lightweight resource footprint.

The correct answer is B. by using AppID results. Junos SSL proxy does not identify SSL/TLS sessions by assuming that encrypted traffic always uses TCP/443. That would be technically weak because SSL/TLS can run on nonstandard ports, and non-SSL applications can also use common HTTPS ports. Juniper’s SSL proxy documentation explains that SSL proxy works with application security services and that AppID is used in the encrypted-traffic inspection workflow. In earlier wording from Juniper AppSecure material, SSL proxy uses application identification services to determine whether a session is SSL encrypted; in current Junos documentation, SSL proxy and AppID are tightly linked so encrypted sessions can be identified, decrypted, inspected, and then re-encrypted for enforcement.

Option A is wrong because the URL is inside the HTTP payload, and in HTTPS much of the meaningful HTTP content is encrypted before SSL proxy inspection occurs. Option C is wrong because destination port is only a rough hint, not a reliable detection method. Option D is wrong because certificates are used in the SSL/TLS handshake and proxy trust model, but the service’s traffic classification relies on AppID results, not merely reading the server certificate. Reference topics: SSL Proxy, AppID, encrypted session detection, SSL/TLS inspection, application security services.

The correct answers are B and C. Adaptive Threat Profiling allows SRX Series Firewalls to act either as inline enforcement devices or as tap-based sensors. In an inline deployment, the SRX is directly in the traffic path and can enforce policy actions such as blocking, denying, or adding threat indicators to Security Intelligence feeds for real-time mitigation. In a tap deployment, the SRX observes copied traffic from a TAP/SPAN-style feed and contributes intelligence without being the active forwarding device. Juniper’s ATP Cloud documentation states that Adaptive Threat Profiling enables SRX devices to be deployed as sensors on Tap ports, identifying and sharing intelligence to inline devices for real-time enforcement. It also describes a “Tap-based SRX Series Firewall sensor” and contrasts it with an inline device.

Option A, bridge, is not the deployment mode being tested here. Bridge/transparent forwarding is a firewall deployment style, not the named Adaptive Threat Profiling mode. Option D, promiscuous, is also wrong; promiscuous mode is an interface behavior, not the ATP Adaptive Threat Profiling deployment model. Reference topics: ATP Cloud, Adaptive Threat Profiling, tap sensors, inline enforcement, Security Intelligence feeds.

The correct answers are B and D. In Junos SSL proxy terminology, client protection maps to SSL forward proxy. In a forward-proxy deployment, the SRX sits between internal clients and external SSL/TLS servers. The firewall intercepts the server certificate, generates a substitute certificate, signs it with the configured root CA, decrypts the SSL session for inspection, and then re-encrypts traffic toward the destination server. Juniper’s SSL proxy configuration table shows that a forward-proxy profile uses root-ca configured = Yes and server-certificate configured = No. It also states that configuring neither certificate type fails commit validation, while configuring both root-ca and server-certificate in the same profile is unsupported.

Option A is wrong because a server certificate is required for reverse proxy/server protection, not for client-protection forward proxy. Option C is wrong because without a trusted root CA, client browsers would not trust the certificates generated by the SRX during interception. Juniper separately notes that the root CA certificate is required for client browsers to trust certificates signed by the firewall. Reference topics: SSL Proxy, client protection, SSL forward proxy, root CA, server protection, SSL reverse proxy.

The correct answers are A and D. Juniper provides predefined IDP policy templates to simplify IDP deployment. These templates are supplied by Juniper Networks and include common templates such as client protection, server protection, DMZ services, DNS server, file server, web server, IDP default, and recommended policies. Juniper’s IDP documentation states that predefined templates are available from a secured Juniper Networks website, and the listed templates are explicitly described as being provided by Juniper Networks.

Option D is correct because these templates are not automatically present as usable policies in a factory-default SRX configuration. Juniper’s procedure says that to use predefined IDP policy templates, you download the policy templates and then install them. The CLI process includes request security idp security-package download policy-templates followed by request security idp security-package install policy-templates; committing then makes them available under the IDP policy hierarchy.

Option B is wrong because Juniper specifically says you should customize these templates for your network and recommends using a copied template so you can safely make changes. Option C is wrong because they must be downloaded and installed, so they are not simply available in the factory-default configuration. Reference topics: IDP, predefined IDP policy templates, security-package download, security-package install, active IDP policy.

The correct answers are A and D. A mobile command center using a 5G ISP behind CGNAT is operating behind dynamic address translation. For IPsec to work reliably through NAT, the SRX must support NAT Traversal, which encapsulates IKE and ESP traffic in UDP/4500 after NAT is detected. Juniper states that NAT-T is used when NAT devices exist in the datapath and that NAT keepalives are required because NAT devices age out UDP translations. Juniper’s Security Director VPN workflow also specifically says to enable NAT-T when the dynamic endpoint is behind a NAT device.

DPD is also required because mobile and carrier-grade NAT connections can disappear, roam, or become stale without a clean tunnel teardown. Juniper defines Dead Peer Detection as the method used by IPsec peers to verify whether the remote peer is still present and responsive by sending encrypted IKE notification payloads and waiting for acknowledgements. Option B is not the best answer because IKEv1 aggressive mode is weaker and does not provide identity protection; Juniper also notes that aggressive mode applies only to IKEv1. Option C is invalid because IKEv2 aggressive mode does not exist. Reference topics: IPsec VPN, NAT-T, CGNAT, dynamic endpoints, DPD, IKE peer availability.

The correct answer is D. You have too many domain controllers. The exhibit shows 15 Active Directory domain controllers. Juniper’s integrated Active Directory identity-source configuration for SRX identity-aware firewall supports a limited number of domain controllers; Juniper documentation states that an SRX Series device can configure a maximum of 10 domain controllers for Active Directory identity-source integration. Because this environment has 15 domain controllers, the direct Active Directory identity-source method exceeds the supported scale and JIMS must be used instead.

Option A is wrong because SRX devices can use Active Directory directly as an identity source; JIMS is not the only possible method. Option B is wrong because 1,500 users does not exceed the relevant identity-source scale shown here; Juniper documentation also notes probe functionality support well above this number. Option C is wrong because the issue being tested is not the Windows Server version. JIMS is designed for larger identity-aware deployments and can centralize identity collection from Active Directory, domain controllers, Exchange servers, and syslog sources, then provide identity mappings to SRX firewalls. Juniper’s JIMS datasheet shows much higher scale, including up to 100 active directories, 25 domains, and 500,000 user entries. Reference topics: Identity-Aware Security Policies, Active Directory identity source limits, JIMS scalability, domain controller scale limitations.

The correct answer is B. ESP. In IPsec, the security protocol responsible for encrypting protected traffic is Encapsulating Security Payload (ESP). Juniper defines ESP as the IPsec protocol used for encrypting the IP packet and authenticating its contents. In practical SRX VPN design, ESP is the normal protocol selected when confidentiality is required because it can provide encryption, packet integrity, authentication, and anti-replay protection depending on the configured IPsec proposal.

Option A, SHA-1, is incorrect because SHA-1 is an authentication/hash algorithm, not an IPsec security protocol and not a payload encryption mechanism. Option C, AH, is incorrect because Authentication Header validates packet source and integrity but does not encrypt payload data. AH is therefore unsuitable when the requirement explicitly says payload data must be encrypted. Option D, PFS, is incorrect because Perfect Forward Secrecy is a key-exchange property used during Phase 2 rekeying; it strengthens key independence but does not itself encrypt packets. In Junos IPsec configuration logic, the security protocol decision is between ESP and AH, and encryption requires ESP. Reference topics: IPsec VPN, ESP, AH, IPsec security protocols, payload confidentiality, IPsec proposal design.

The correct answer is D. exempt. In Junos IDP, the exempt rulebase is specifically used to prevent selected traffic from triggering known false-positive detections. Juniper’s IDP documentation explains that exempt rules can be configured when an IDP policy generates false positives for a particular attack object, source, destination, or traffic pattern. The exempt rulebase lets the administrator exclude matching traffic from attack detection while still allowing the rest of the IDP policy to inspect other traffic normally.

Option A, IPS, is wrong because the IPS rulebase is the main inspection rulebase used to detect and act on attacks. It is where attack objects and actions are commonly applied, but it is not the rulebase designed to eliminate false positives. Option B, monitor, is not the correct false-positive elimination mechanism. Monitoring can help observe behavior, but it does not exempt traffic from matching an attack object. Option C, signature, is wrong because signatures are attack-detection patterns, not a rulebase type used to suppress false positives. The operational correction for noisy or irrelevant matches is to create an exempt rule for the specific trusted source, destination, or attack object. Reference topics: IDP rulebases, exempt rulebase, false-positive tuning, attack objects, IPS inspection.

The correct answers are A and B. In an SRX chassis cluster, the cluster ID identifies the chassis cluster, and valid operational cluster IDs are nonzero values. Juniper’s chassis cluster command documentation states that the system uses the chassis cluster ID and node ID to apply the correct node-specific configuration, and the command writes the chassis cluster ID and node ID to EPROM. When the cluster ID is set to 0, clustering is disabled; therefore, the HA cluster configuration is effectively ignored because the device is no longer operating as a chassis-cluster member.

Option B is also correct because Juniper states that chassis cluster ID and node ID changes take effect only after the system is rebooted. That is why the operational command format includes the reboot behavior when setting cluster-id and node. Option C is wrong because node ID 0 is valid; it identifies node0 in the two-node cluster. Option D is wrong because SRX chassis clusters use node IDs 0 and 1 only; the 1–255 range applies to cluster IDs, not node IDs. Reference topics: HA Clustering, cluster ID, node ID, EPROM, chassis cluster enablement, node-specific configuration.

The correct answers are B and D. In VPN cryptography, hashing is used for authentication and integrity checking, not confidentiality. Juniper’s IPsec documentation describes MD5 as producing a 128-bit hash, also called a digital signature or message digest, from a message of arbitrary length. It also describes SHA as producing a 160-bit hash from a message of arbitrary length. That directly supports option B because a hash function takes variable-length input and produces a fixed-size digest.

Option D is also correct because Juniper states that the resulting hash is used like a fingerprint of the input to verify content and source authenticity and integrity. Juniper’s IPsec overview further explains that Junos compares the calculated message digest against the expected digest to verify that the message has not been tampered with.

Option A is wrong because hashing is not compression; it is one-way digest generation. Option C is wrong because encryption protects confidentiality, while hashing validates integrity and authenticity. In IPsec, algorithms such as AES, DES, and 3DES provide encryption, while MD5, SHA-1, and SHA-2 provide hashing/HMAC-based authentication. Reference topics: IPsec VPN, hashing, HMAC, MD5, SHA, message digest, data integrity.

The correct answers are A and B. In an SRX chassis cluster, the cluster ID identifies the chassis cluster itself, while the node ID identifies the individual SRX device inside that two-node cluster. Juniper states that a cluster is identified by a cluster-id value from 1 through 255, and that setting the cluster ID to 0 is equivalent to disabling clustering. Therefore, option A is correct and option C is wrong.

Option B is also correct because Juniper states that a cluster node is identified by a node ID specified as a number from 0 through 1. A normal SRX chassis cluster has two nodes: node0 and node1. The two devices must use the same nonzero cluster ID so they belong to the same cluster, but each device must use a different node ID so Junos can apply node-specific configuration, interface numbering, redundancy-group ownership, and management settings correctly. Option D is wrong because node IDs do not range from 1 through 255; that range applies to cluster IDs, not node IDs. Reference topics: HA Clustering, cluster ID, node ID, chassis cluster formation, node0/node1 identification.

The correct answers are A and D. In IKEv1-based IPsec VPNs, there are two distinct negotiation phases. IKEv1 Phase 1 establishes the secure and authenticated IKE channel between peers. That means the IKE SA is built during Phase 1. Juniper describes Phase 1 as the negotiation of proposals for how to authenticate and secure the channel, including encryption algorithms, authentication algorithms, Diffie-Hellman group, and authentication method.

IKEv1 Phase 2 then uses that secure channel to negotiate the IPsec SAs that protect actual user traffic through the VPN. Juniper states that Phase 2 negotiates security associations to secure the data traversing the IPsec tunnel, and that the Phase 2 proposal includes the security protocol, such as ESP or AH, plus the selected encryption and authentication algorithms. Option B is wrong because IKEv1 SAs are not established in Phase 2; Phase 2 creates IPsec SAs. Option C is wrong because Phase 1 does not create the data-plane IPsec SA; it creates the secure IKE control channel used for Phase 2 negotiation. Reference topics: IPsec VPN, IKEv1 Phase 1, IKE SA, IKEv1 Phase 2, IPsec SA, ESP/AH proposals.

The correct answer is A. the action taken is defined in the IDP policy that includes this attack object. The exhibit defines a custom attack object named BGP-DEFEND under the security idp custom-attack hierarchy. The custom object includes metadata such as recommended-action drop, severity critical, and signature match conditions such as BGP update AS-path context and pattern 65501. However, an attack object by itself does not determine the final enforcement behavior. The attack object defines what to match; the IDP policy rule that references the object defines what action to take when that match occurs. Juniper describes attack objects as objects used inside IDP rules to identify malicious activity, while IDP rules include rule actions such as drop-packet, drop-connection, close-client, close-server, recommended, and others.

Option B is wrong because the firewall security policy enables IDP inspection by applying an IDP policy, but the IDP action is not selected directly by the normal security policy. Options C and D are too absolute. Even though the custom object shows recommended-action drop, that is only used if the IDP rule action invokes recommended behavior. Without seeing the IDP policy rule action, you cannot conclude reject or drop. Reference topics: IDP custom attack objects, IDP policy rule actions, recommended action, signature-based attack matching.

The correct answers are A and B. In SRX chassis clustering, the fabric link, represented by fab interfaces, is the data-plane connection between the two cluster nodes. Juniper describes the fabric as the back-to-back data connection used when traffic on one node must be processed on the other node or must exit through an interface on the other node; session-state information also passes over the fabric. This is especially visible in active/active clustering, where ingress and egress interfaces can reside on different nodes and transit traffic must cross the fabric link.

Option B is also correct because the fabric link still exists in active/passive clustering for cluster data-plane synchronization and inter-node state handling, even though active/passive designs minimize fabric transit traffic because only one node normally forwards traffic at a time. Juniper specifically states that active/passive mode minimizes traffic over the fabric link, not that the fabric link is unused.

Options C and D are not the intended answers. The cluster is identified by a configured cluster ID, and each chassis is identified by a node ID, but the fabric interface names themselves are not where the cluster ID is reflected. Reference topics: HA Clustering, fabric link, active/active clustering, active/passive clustering, session synchronization, inter-node traffic.

The correct answers are B and C. Juniper IDP uses attack objects as match conditions inside IDP policy rules. Juniper states that IDP attack objects represent known and unknown attacks and that the predefined attack object database is periodically updated by Juniper Networks. The main IDP attack object types include signature attack objects, protocol anomaly attack objects, and compound attack objects.

Option C is correct because signature attack objects detect known attacks using stateful attack signatures. Juniper defines a signature as a pattern that exists within a specific section of an attack and includes protocol, service, direction, flow, and context information to reduce false positives.

Option B is correct because protocol anomaly attack objects detect abnormal protocol behavior. Juniper explains that protocol anomaly objects identify unusual or ambiguous traffic that violates protocol specifications, RFCs, or common RFC extensions.

Option A is wrong because “statistic-based” is not one of the IDP attack object database types being tested here. Option D is wrong because “vector-based” is not a Juniper IDP attack object type. Reference topics: IDP, attack object database, signature-based attack objects, protocol anomaly attack objects, predefined attack objects.