JNCIA-SEC Monitoring And Troubleshooting — 20 Questions

Question 1

An engineer needs to troubleshoot asymmetric routing issues where return traffic bypasses the SRX firewall. Which flow option can be enabled to handle asymmetric paths?

Accepted Answer

set security flow tcp-session no-syn-check. Enabling syn-flood-protection or stateless-flow options can help, but flow-based setting 'tcp-session no-syn-check' allows sessions to establish without seeing the initial SYN packet.

Answer

set security flow asymmetric-routing permit

Answer

set routing-options instance-type virtual-router

Answer

set security policies bypass-reverse-path

Question 2

An administrator wants to view log messages generated by security policies. Which syslog facility is typically used by Junos security policies for logging event messages?

Accepted Answer

local0 through local7. Security policies log events to the user facility or daemon facility depending on configuration, but security-specific log messages are typically directed to security-related facilities like RT_FLOW.

Answer

kernel

Answer

auth

Answer

security

Question 3

When troubleshooting screen options (DoS/attack protection) dropping legitimate traffic, which TWO commands or configurations should you inspect? (Choose three) Wait, the prompt says HALF use Which THREE. This is a Which THREE question. Which THREE commands or configurations should you inspect? (Choose three)

Accepted Answer

show log messages or check syslog for screen drop entries. Screen options drop counters, zone screen configuration, and system logs provide insight into screen drops.

Answer

show security flow session detail

Answer

show security ike security-associations

Question 4

An administrator needs to view active sessions matching a specific destination port on an SRX Series device. Which command syntax is correct?

Accepted Answer

show security flow session destination-port 443. The show security flow session destination-port command allows filtering sessions based on destination port numbers.

Answer

show security policy match-port 443

Answer

show route protocol bgp port 443

Answer

show firewall filter port 443

Question 5

You are troubleshooting a packet drop issue on an SRX Series device and need to trace packets for a specific source IP address. Which feature should you configure to capture detailed packet flow logs?

Accepted Answer

set security flow traceoptions file flow-debug. Security flow traceoptions allow administrators to track packet processing steps through the security engine, capturing drop reasons and state changes.

Answer

set system syslog file packet-log

Answer

request security app-firewall log clear

Answer

set firewall filter debug term 1 then count

Question 6

While inspecting the security session table using 'show security flow session', you notice a session in the 'P' state. What does this state indicate?

Accepted Answer

The session is pending and waiting for a TCP synchronization or return packet to be fully established.. In Junos OS SRX session management, the 'P' flag indicates a pending session waiting for a return packet or complete three-way handshake before becoming active.

Answer

The session is prioritized for quality of service (QoS).

Answer

The session is operating in passive FTP mode.

Answer

The session is permanently blocked due to a security policy violation.

Question 7

You need to verify the operational status of an IPsec VPN tunnel on an SRX Series device. Which command provides detailed tunnel status including Phase 1 and Phase 2 associations?

Accepted Answer

show security ipsec security-associations. The show security ike security-associations and show security ipsec security-associations commands are used to inspect VPN tunnels.

Answer

show security flow vpn-status

Answer

show security ike sa-detail

Answer

show vpn ipsec active

Question 8

Where are system log messages related to security policies typically directed when default logging configurations are used?

Accepted Answer

To the local log file configured under system syslog, such as interactive-commands or security-log. Security policy logs are sent via security daemon (secd) and flow module to the local syslog utility, usually directed to a file or remote collector.

Answer

Directly to the active user terminal screen by default

Answer

To the kernel crash dump utility

Answer

To the boot-time NVRAM partition

Question 9

You suspect that Network Address Translation (NAT) is misconfigured for a server pool. Which command should you use to examine active NAT translation entries?

Accepted Answer

show security nat translation. The show security nat source rule-all or show security flow session with NAT details provides insight into active translations, but show security nat translation is the dedicated command for viewing current NAT mappings.

Answer

show route forwarding-table destination-nat

Answer

show security alg status

Answer

show security flow active-nat

Question 10

An administrator notices that traffic between two trusted security zones is being dropped unexpectedly. Which command should be used first to verify if the security policy is matching the traffic?

Accepted Answer

show security policies hit-count. The show security policies hit-count command displays the number of times a specific security policy has matched traffic, confirming if the policy evaluation is occurring as expected.

Answer

show system alarms

Answer

show security flow session

Answer

show route

Question 11

How can an administrator check the active Junos OS version running on an SRX Series device?

Accepted Answer

show version. The show version command displays the active software version and hardware model details.

Answer

show system software-status

Answer

show chassis version

Answer

show system package installed

Question 12

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.. CLOSE-WAIT is a standard TCP state indicating that the local endpoint has received a connection termination request (FIN) from the remote side and is waiting for the local application to close.

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 13

Which command allows an administrator to view real-time interface throughput and error statistics on an SRX Series firewall?

Accepted Answer

show interfaces statistics. The show interfaces command displays interface traffic rates, drops, and error statistics.

Answer

show system interface status

Answer

show chassis hardware

Answer

show security flow statistics

Question 14

Which command is used to display current CPU and memory utilization on an SRX Series services gateway?

Accepted Answer

show system processes summary. The show system्ह resource or show system processes command family provides resource utilization, with show system information or show chassis routing-engine being standard.

Answer

show security resource-utilization

Answer

show route summary-statistics

Answer

show chassis cpu-memory

Question 15

An administrator wants to monitor security screening checks such as SYN flood protection counters. Which operational command should be used?

Accepted Answer

show security screen statistics. Screen options protect against attacks, and their statistics are viewed using show security screen statistics.

Answer

show system screening-counters

Answer

show security attack-mitigation status

Answer

show security flow flood-protection

Question 16

An administrator configures traceoptions for security policies. Where can they find the resulting log output file?

Accepted Answer

/var/log/. Security policy traceoptions log files are written by default to /var/log/ directory on the Routing Engine.

Answer

/config/trace/

Answer

/tmp/

Answer

/var/db/

Question 17

You need to verify whether application identification (AppID) is successfully classifying traffic within security policies. Which command displays AppID session details?

Accepted Answer

show security flow session extensive. The show security alg status or show security flow session extensive commands show application details associated with active sessions.

Answer

show application-firewall status

Answer

show security policies app-id-hits

Answer

show security app-tracking summary

Question 18

An administrator enables traceoptions for IKE to troubleshoot a failing VPN negotiation. Where are these trace files stored by default on the SRX Series device?

Accepted Answer

/var/log/. Traceoptions files are stored in the /var/log/ directory by default on Junos OS devices.

Answer

/var/tmp/traces/

Answer

/etc/log/ike/

Answer

/config/sec/

Question 19

Which command displays the current active security policies applied on an SRX Series device?

Accepted Answer

show security policies. The show security policies command displays configured security policies and their rules.

Answer

show security zone policies

Answer

show route security-policy

Answer

show firewall security-rules

Question 20

What is the purpose of the 'show security zones' command?

Accepted Answer

To display configured security zones and their associated interfaces and properties. The show security zones command displays security zones, associated interfaces, and zone-level screen/policy settings.

Answer

To show routing table partitions

Answer

To list all active IPsec VPN tunnels

Answer

To monitor firewall CPU load per zone