A. The amount of decrypted traffic

Explanation:
The dataplane CPU is responsible for handling traffic processing, which includes:
Session setup and teardown
Security policy enforcement
Content inspection (threat prevention, URL filtering, WildFire analysis, etc.)
SSL/TLS decryption and re-encryption (a very CPU-intensive operation)
🔹 When dataplane CPU is high, one of the first tuning levers is to check how much traffic is being decrypted. SSL/TLS decryption (especially with strong ciphers) can significantly increase load. Reducing the amount of decrypted traffic (by excluding certain trusted traffic or unnecessary categories like streaming or updates) will directly reduce dataplane CPU utilization.

Why the other options are incorrect:
B. The timeout value for admin sessions ❌
Admin sessions (WebUI/CLI) consume management plane CPU, not dataplane CPU.
Adjusting timeout values won’t affect dataplane utilization.
C. The number of mapped User-ID groups ❌
User-ID group mapping impacts management plane memory/processing (handling group lookups from AD/LDAP), not dataplane CPU.
D. The number of permitted IP addresses on the management interface ❌
This affects management plane access (which IPs can reach the management interface).
It has no effect on dataplane CPU load.

Reference:
Palo Alto Networks TechDocs: Monitor Firewall Resources
Best Practices: Reduce SSL Decryption Overhead

A. While troubleshooting

Explanation:
Logging at session start is best used during troubleshooting to gain immediate visibility into traffic as sessions begin. This setting allows the firewall to generate a log entry as soon as a session is initiated, which helps identify whether a rule is matching, what application is detected early, and whether traffic is being allowed or denied.

This is particularly useful when:
Diagnosing rule matching issues
Investigating long-lived sessions (e.g., SSH, RDP)
Monitoring traffic that may not terminate cleanly or quickly
However, enabling session start logging globally or permanently is not recommended. It increases log volume significantly and can place additional load on the management plane, especially in high-throughput environments. Palo Alto Networks recommends using “Log at Session End” for regular logging, as it provides complete session details including bytes transferred, duration, and final application identification.

❌ Why Other Options Are Incorrect:
B. Only on Deny rules While logging deny actions is important, session start logging is not limited to deny rules. It’s more broadly useful for troubleshooting any rule behavior.
C.On all Allow rules Logging at session start on all allow rules is excessive and not a best practice. It can overwhelm log storage and reduce performance.
D. Only when log at session end is enabled Session start and session end logging are independent options. You can enable one or both depending on your visibility needs.

🔗 Valid References:
Palo Alto Networks Knowledge Base: Session Log Best Practices
Reddit Discussion: Log Size After Enabling Log at Session Start

C. Resources Widget on the Dashboard

Explanation:
To view CPU utilization for both the management plane and data plane on a Palo Alto Networks firewall, the administrator should use the Resources widget on the Dashboard. This widget provides real-time visibility into system performance metrics, including:

Management Plane CPU:
Reflects usage by system processes such as routing daemons, authentication services, and the web interface.
Data Plane CPU:
Indicates how much processing power is being used to handle traffic, session management, and packet forwarding.

This widget is accessible via:
Web UI > Dashboard > Widgets > Resources
It offers a quick and centralized view of system health, helping administrators identify performance bottlenecks, excessive load, or potential hardware issues.

❌ Why Other Options Are Incorrect:
A. Support > Resources This section is used for support-related diagnostics and file generation, not for live CPU monitoring.
B. Application Command and Control Center (ACC) ACC provides visibility into traffic patterns, threats, and applications—not system resource usage.
D. Monitor > Utilization This tab shows interface and bandwidth statistics, not CPU metrics for management or data planes.

References:
Palo Alto Networks TechDocs:Dashboard Widgets Overview
LIVEcommunity Discussion: How Management CPU and Data Plane CPU Work Exam4Training PCNSE Practice: Where to View CPU Utilization

A. A secondary DNS server in the DNS proxy is optional, and configuration commit to the firewall will succeed with only one DNS server.

Explanation:
When configuring DNS Proxy for Explicit Proxy (web proxy), the firewall allows you to specify primary and secondary DNS servers. However, the configuration validation only requires a primary DNS server to be defined. The commit operation will succeed with just one DNS server configured.

Why the other options are incorrect:
B. A maximum of two FQDNs can be mapped to an IP address in the static entries for DNS proxy:
This is false. There is no hard-coded limit on the number of FQDNs that can be mapped to a single IP address in the static entries of the DNS proxy configuration.
C. DNS timeout for web proxy can be configured manually, and it should be set to the highest value possible:
This is incorrect and not a best practice. The DNS timeout value should be set appropriately based on network conditions. Setting it to an excessively high value could cause unnecessary delays in DNS resolution and degrade user experience.
D. Adjust the UDP queries for the DNS proxy to allow both DNS servers to be tried within 20 seconds:
This is misleading. The default behavior of the DNS proxy is to query the primary server first, and if no response is received within the configured timeout (default is 2 seconds), it will try the secondary server. The total time for both attempts is not fixed at 20 seconds; it depends on the configured timeout and number of retries.

Reference:
Palo Alto Networks Administrator Guide:
The "DNS Proxy" section confirms that while multiple DNS servers can be configured for redundancy, only one is required for a valid configuration.
PCNSE Exam Blueprint (Domain 2:
Deployment and Configuration): Understanding DNS proxy configuration for explicit proxy deployments is a key objective within the blueprint.

B. High
C. Critical
E. Medium

Explanation:
Palo Alto Networks publishes Threat Prevention Best Practices that define recommended settings for Security Profiles (Vulnerability, Anti-Spyware, AV, URL, etc.).

For Anti-Spyware Profiles, best practices include:
Enable single-packet capture for severities Medium, High, and Critical
→ This allows administrators to analyze malicious sessions more effectively without capturing unnecessary benign traffic.
Do NOT enable packet capture for Low or Informational severities
→ These typically represent lower-risk or informational events that would unnecessarily consume disk space and processing.
🔹 So, Medium + High + Critical = the three severity levels where single-packet capture should be enabled.

Why not the others?
A. Low ❌ → Too much noise, not best practice.
D. Informational ❌ → Only logs metadata, doesn’t require packet capture.

Reference:
Palo Alto Networks TechDocs: Anti-Spyware Profile Best Practices
Best Practice Guidance: Enable Single-Packet Capture for medium, high, and critical severities.

B. > show system state filter-pretty sys.sl.p8.phy

Explanation:
The question asks for the CLI command that displays the physical media connected to ethernet1/8 on a Palo Alto Networks firewall. This requires identifying a command that provides detailed interface information, specifically related to the physical layer (e.g., media type, connection status). Let’s evaluate the options to determine the correct one.

Why > show system state filter-pretty sys.sl.p8.phy?
Purpose:
The show system state filter-pretty command is used to display detailed system state information in a human-readable format, filtered by specific parameters. The filter sys.sl.p8.phy targets the physical layer details of slot 1, port 8 (corresponding to ethernet1/8, where "p8" denotes port 8). This command provides information about the physical media, such as the type of cable or connection (e.g., copper, fiber) and its status.
Output:
The command will display details like the media type, link state, and speed/duplex settings for ethernet1/8. This is useful for troubleshooting physical connectivity issues.
Syntax Breakdown:
sys: System state.
sl: Slot (typically 1 for most firewalls, as ethernet1/8 is in slot 1).
p8: Port 8 (matching ethernet1/8).
phy: Physical layer information.
Reference:
Palo Alto Networks CLI Reference Guide indicates that show system state filter-pretty sys.sl.pX.phy is used to view physical media details for a specific port, where pX is the port number.

Why Not the Other Options?
A. > show system state filter-pretty sys.si.p8.stats:
Explanation:
The filter sys.si.p8.stats likely refers to interface statistics (e.g., packet counters) for port 8 in slot 1. While this provides performance data, it does not specifically display physical media details (e.g., cable type or connection status).
Why Incorrect: This command focuses on statistics, not physical media.
C. > show system state filter-pretty sys.sl.p8.med:
Explanation:
The filter sys.sl.p8.med appears to be a typo or incorrect syntax. There is no standard med parameter in the show system state command for physical media; the correct term is phy for physical layer details. This command would likely return no meaningful output or an error.
Why Incorrect: Invalid filter syntax makes this option non-functional.
D. > show interface ethernet1/8:
Explanation:
The show interface ethernet1/8 command displays operational status and configuration details for the specified interface, including IP address, speed, duplex, and link state. While it provides some physical layer information (e.g., link up/down), it is less detailed than the show system state filter-pretty sys.sl.p8.phy command for physical media specifics (e.g., media type).
Why Incorrect: This command is broader and less targeted to physical media details compared to the correct option.

Additional Context:
Interface Naming: On Palo Alto Networks firewalls, ethernet1/8 refers to slot 1, port 8. The CLI uses this notation to identify physical interfaces.
Troubleshooting Tip: To verify physical connectivity, use > show system state filter-pretty sys.sl.p8.phy alongside > show interface ethernet1/8 for a comprehensive view. Best Practices:
Check cable type and compatibility (e.g., copper vs. fiber) using the physical media details. Ensure the interface is administratively up (> configure; set interface ethernet1/8 enable yes).
PCNSE Exam Relevance: This question tests your knowledge of CLI commands for interface troubleshooting, a key skill in the PCNSE exam. It requires understanding the nuances of show system state filters.

Conclusion:
The CLI command that displays the physical media connected to ethernet1/8 is > show system state filter-pretty sys.sl.p8.phy, as it specifically targets the physical layer details for that port.

References:
Palo Alto Networks CLI Reference Guide: System State Commands
Palo Alto Networks Documentation: Interface Management
ExamTopics PCNSE Discussion: CLI Interface Commands

B. The firewall evaluates the profiles in top-to-bottom order until one Authentication profile successfully authenticates the user.

Explanation:
When you configure Authentication Sequences on a Palo Alto firewall:
You first create individual Authentication Profiles (e.g., Kerberos, LDAP, TACACS+).
Then you create an Authentication Sequence, which lists those profiles in a top-to-bottom order.

During authentication:
The firewall checks the first profile in the list.
If it fails (e.g., user not found or authentication denied), it moves to the next profile in the sequence.
The process continues until one profile succeeds, or all fail.
📘 Reference:
Palo Alto Networks – Configure Authentication Sequences

❌ Why not the other options?
A. Alphabetical order
→ Incorrect. The order is explicitly defined by the admin in the Authentication Sequence, not by profile name.
C. Priority assigned
→ Incorrect. There is no numeric priority setting; the list order defines priority.
D. No further attempts if first times out
→ Incorrect. If the first method times out or fails, the firewall continues to the next profile in the sequence.