JNCIA-SEC Practice Test 26 — 15 Questions

Question 1

An administrator needs to configure basic web filtering on a Juniper SRX Series device using the Integrated Web Filtering feature. Which license is strictly required on the SRX Series device to enable communication with the cloud-based web filtering rating server?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

An Integrated Web Filtering license. Integrated Web Filtering on Juniper SRX devices relies on cloud-based categorization servers, which requires a valid Sophos or Webroot web filtering license installed on the device.

Answer

An IDP (Intrusion Detection and Prevention) license

Answer

An AppSecure license

Answer

An Anti-Virus license

Question 2

Which Junos command displays active alarms on an SRX Series device, helping you quickly identify hardware faults or system errors?

Accepted Answer

show system alarms. The 'show system alarms' command is the standard Junos operational command that displays all active alarms on an SRX Series device, including chassis, hardware, and system-level alarms. It provides a consolidated view of any conditions that require administrative attention, such as fan failures, power supply issues, or temperature thresholds being exceeded. This is the go-to command for quickly assessing device health and identifying faults.

Answer

show fault status

Answer

show active warnings

Answer

show error logs

Question 3

Which TWO actions occur when an Application Layer Gateway (ALG) inspects traffic in Junos OS? (Choose two)

Accepted Answer

The ALG parses application-layer control messages to identify dynamic port negotiations.. ALGs inspect application control channels and dynamically open data sessions for complex protocols.

Answer

The ALG converts all UDP traffic into reliable TCP byte streams.

Answer

The ALG replaces the standard IPsec encryption engine for high-throughput VPN tunnels.

Answer

The ALG blocks all encrypted traffic unconditionally.

Question 4

Which utility or interface provides a browser-based graphical management interface built directly into Junos OS on SRX Series devices?

Accepted Answer

J-Web. J-Web is a browser-based graphical management interface that is built directly into Junos OS on SRX Series devices. It allows administrators to configure, monitor, and manage the device through a web browser without requiring additional software. J-Web is accessed via HTTPS and provides a user-friendly alternative to the CLI.

Answer

Network Director

Answer

Security Director Cloud

Answer

Junos Space

Question 5

An administrator configures a Source NAT pool containing a single public IP address. Multiple internal users browse the web simultaneously. How does Junos OS distinguish between simultaneous sessions originating from different internal private IP addresses destined for the same external web server on port 80?

Accepted Answer

By translating each internal source IP and ephemeral port combination into a unique source port on the single public IP address (PAT).. When a source NAT pool has a single public IP, Junos uses Port Address Translation (PAT) — also called NAT overload — to multiplex multiple internal sessions onto that one IP. Each internal source IP and ephemeral port combination is translated to a unique source port on the public IP, so the SRX can distinguish sessions by the (public IP, source port) tuple and reverse the translation correctly for return traffic.

Answer

By modifying the destination port to a unique value for each internal user session.

Answer

By assigning virtual MAC addresses to each session in the ARP table.

Answer

By queuing sessions and processing them sequentially through the single IP address.

Question 6

Which Junos configuration hierarchy is used to create a UTM Policy Profile that bundles multiple security features?

Accepted Answer

[edit security utm policy-profile ]. The correct Junos hierarchy for creating a UTM policy profile is [edit security utm policy-profile ]. This hierarchy bundles multiple UTM features — antivirus, anti-spam, content filtering, web filtering, and application firewall — into a single profile that can then be referenced in a security policy. The exact path is critical because Junos uses a strict hierarchical configuration model.

Answer

[edit security policies utm-profile <name>]

Answer

[edit utm profile-policy <name>]

Answer

[edit security firewall utm-policy <name>]

Question 7

An administrator configures an application set in Junos OS. What is the primary function of an application set?

Accepted Answer

To combine multiple individual applications into a single group for easier policy management.. An application set allows grouping multiple individual application objects or other application sets into a single logical object for use in security policies.

Answer

To bind specific applications to specific Layer 2 VLAN IDs.

Answer

To translate non-standard ports to standard application ports dynamically.

Answer

To automatically enable ALGs for all bundled protocols.

Question 8

An administrator configures a security zone and enables traceoptions for security flow. Where are these traceoptions configured in the Junos OS hierarchy?

Accepted Answer

[edit security flow traceoptions]. Flow traceoptions are configured under the [edit security flow traceoptions] hierarchy to troubleshoot session and flow processing.

Answer

[edit security zones security-zone trust traceoptions]

Answer

[edit firewall traceoptions]

Answer

[edit system traceoptions security-flow]

Question 9

You are analyzing security flow traceoptions while troubleshooting a failing Source NAT scenario. The trace output indicates: 'NAT error: no available ports in pool'. However, a concurrent check of the pool using operational commands shows that only a fraction of the pool's IP addresses are currently utilized. What is the cause of this behavior?

Accepted Answer

The source IP has exhausted the port allocation on its assigned pool address, and port sharing across multiple pool IPs is not enabled.. The error 'no available ports in pool' means the SRX has exhausted the ephemeral port range on the specific pool IP address currently assigned to that source. Junos source NAT with interface or pool-based translation allocates ports per pool address; if port sharing across multiple pool IPs is not enabled (or the source is pinned to one address), the device will not spill over to other underutilized IPs in the pool. Enabling port sharing or using address-persistent/round-robin allocation allows the SRX to distribute sessions across all pool addresses.

Answer

Interface-based NAT is overriding the pool-based NAT configuration due to a rule-set ordering conflict.

Answer

The SRX device has reached its maximum global session limit across all security contexts.

Answer

Proxy ARP is blocking additional port allocation from the upstream gateway.

Question 10

Which TWO actions can help an administrator troubleshoot why a security policy is not matching expected traffic? (Choose two)

Accepted Answer

Check policy hit counts using 'show security policies hit-count'. Option B is correct because 'show security policies hit-count' displays the per-policy match counters, allowing the administrator to verify whether the expected policy is actually being evaluated and matched by the traffic in question. Option D is correct because flow traceoptions (configured under 'security flow traceoptions') capture detailed packet-processing information, including which policy, zone, and rule the security engine evaluates for a given flow, which is the definitive way to see why traffic does or does not match a policy. Option A is incorrect because clearing the BGP routing table only affects route reachability and does not influence security policy matching logic. Option C is incorrect because resetting physical interface duplex settings addresses Layer 1/2 link issues, not policy evaluation. Option E is incorrect because restarting rpd only reloads routing protocol state and has no bearing on how the security engine matches traffic against policies.

Answer

Clear the BGP routing table

Answer

Reset physical interface duplex settings

Answer

Restart the routing protocol daemon (rpd)

Question 11

Which THREE checks should be performed when troubleshooting source NAT translation failures? (Choose three)

Accepted Answer

Verify that the source NAT rule is active and correctly applied to the traffic zone. Option A is correct because a source NAT rule must be enabled and matched to the correct traffic zone (source/destination zone and interface) for translation to occur; an inactive or misapplied rule causes translation failures. Option B is correct because security policies must allow the traffic from the source zone to the destination zone before NAT processing can succeed; a denied policy prevents the session and thus the NAT translation. Option D is correct because if the source NAT pool is exhausted (all addresses in use), new sessions cannot be translated and will fail. Option C is not correct because IKE Phase 1 authentication keys relate to IPsec VPN tunnel establishment, not source NAT translation. Option E is not correct because static route metrics affect path selection, not whether source NAT translation itself succeeds.

Answer

Check IKE Phase 1 authentication keys

Answer

Verify that static routing table metrics are set to preferred values

Question 12

Which statement best describes an Application Layer Gateway (ALG) in Junos OS?

Accepted Answer

An ALG inspects application traffic and dynamically opens data sessions for protocols that use multiple ports.. ALGs inspect application payloads, handle dynamic port negotiation, and assist the security flow module in tracking complex protocols.

Answer

An ALG is a functional zone used for isolating guest wireless traffic.

Answer

An ALG replaces the need for security policies on transit traffic.

Answer

An ALG is a hardware-based chip on SRX platforms used exclusively for IPsec encryption acceleration.

Question 13

You are troubleshooting a high-throughput SRX deployment using Pool-based Source NAT with PAT. Users report random connection drops during peak business hours. You run 'show security nat pool' and see that pool utilization is low, but traceoptions show 'resource allocation failure: port limit exceeded'. What is the most precise explanation for this condition?

Accepted Answer

Individual source IP port limits have been reached on the assigned pool address, requiring port-sharing or dynamic allocation adjustments.. The error 'resource allocation failure: port limit exceeded' indicates that the individual source IP port limits have been reached on the assigned pool address. Even though pool utilization is low, a single IP in the pool may have exhausted its available ports, requiring port-sharing or dynamic allocation adjustments. This is a common issue in high-throughput NAT scenarios.

Answer

Proxy ARP is rate-limiting the ARP reply frequency for source NAT public IPs.

Answer

The SRX control plane CPU is throttling NAT session creation due to security policy evaluation lag.

Answer

Destination NAT rules are consuming source NAT pool ports.

Question 14

During session troubleshooting, you notice sessions entering the 'CLOSE-WAIT' state and lingering. What does this indicate in the Junos session table?

Accepted Answer

The local application has not yet issued a close command after receiving a FIN from the remote peer.. The 'CLOSE-WAIT' state in the Junos session table indicates that the local application has received a FIN from the remote peer but has not yet issued its own close command. This means the local side is waiting for the application to close the connection. It is a normal part of the TCP connection termination process, but lingering sessions may indicate an application not properly closing sockets.

Answer

The SRX security policy is actively dropping packets for this session.

Answer

IPsec Phase 2 re-keying is in progress.

Answer

The session is awaiting NAT port reallocation.

Question 15

An administrator is analyzing session table output using 'show security flow session' and notices a session in the 'NSRC' (NAT Source) state. What does this specific state indicate about the session?

Accepted Answer

The session is waiting for source NAT translation allocation to be completed.. The NSRC (NAT Source) state indicates that the session is waiting for source NAT translation allocation to complete. This occurs when the SRX is in the process of selecting a NAT source port and IP for the outbound packet, typically during the first-packet processing before the session becomes fully established.

Answer

The session has failed security screening checks and is dropped.

Answer

The session has been closed and is waiting for the TCP TIME-WAIT purge timer.

Answer

The packet is destined for the routing engine control plane.