B. High Risk

Explanation:
SSL decryption is resource-intensive, so it should be deployed strategically to maximize security ROI. The High Risk category includes sites known for malware, phishing, command-and-control (C2) activity, and other malicious content. Decrypting traffic to these sites first allows the firewall to:
Inspect encrypted threats that would otherwise evade detection.
Block dangerous traffic before it causes harm.
Prioritize limited decryption resources on the highest-risk traffic.
This approach aligns with Palo Alto Networks' best practices for phased decryption rollout, starting with the most critical threats.

Why the other options are incorrect:
A. Online Storage and Backup:
While this category may contain threats, it is not the highest priority. Decrypting storage traffic can raise privacy concerns and may be subject to compliance restrictions. C. Health and Medicine: This category is often sensitive due to privacy regulations (e.g., HIPAA). Decrypting it without careful consideration may violate compliance requirements.
D. Financial Services:
This category is critical for security but often uses certificate pinning or is highly sensitive to user privacy. Decrypting financial traffic can break applications or trigger legal issues if not handled cautiously.

Reference:
Palo Alto Networks Best Practices for SSL Decryption:
Recommends starting decryption with the High Risk category to quickly reduce the attack surface.
PCNSE Exam Blueprint (Domain 3:
Security Policies and Profiles): Understanding decryption strategies and prioritization is key for effective security policy design.

B. ECDHE
D. DHE

Explanation:
The resource consumption during SSL/TLS decryption is primarily driven by the key exchange process. The firewall, acting as a SSL Forward Proxy, must perform the cryptographic computations for both the client and server sides of the connection.

The key differentiator is whether the key exchange uses Ephemeral keys. Ephemeral key exchange methods generate a temporary, unique key for each session, which provides Perfect Forward Secrecy (PFS). This enhanced security comes at the cost of significantly higher computational overhead.

D. DHE (Diffie-Hellman Ephemeral):
This is the classic ephemeral key exchange algorithm. It is very computationally intensive for both the client and the server (in this case, the firewall performing decryption) because it involves complex modular exponentiation calculations for every single new session.

B. ECDHE (Elliptic Curve Diffie-Hellman Ephemeral):
This is the elliptic curve variant of DHE. While ECDHE is more efficient than DHE for the same level of security (it uses smaller key sizes), it is still significantly more resource-intensive than non-ephemeral methods like RSA. The elliptic curve operations, though efficient, must still be performed for every new session, leading to high CPU consumption on the firewall when decrypting a large volume of connections.

Why the other options are incorrect:
A. ECDSA (Elliptic Curve Digital Signature Algorithm):
This is used for authentication (proving the server's identity), not for key exchange. While it does use CPU cycles, its impact is minor compared to the ongoing overhead of ephemeral key exchange algorithms. The question specifically asks about the key exchange process.

C. RSA:
In a key exchange context, RSA is a non-ephemeral method. The server's static RSA private key is used to encrypt the pre-master secret. This operation is computationally expensive, but it is only performed once per session during the handshake and is generally less CPU-intensive than the sustained calculations required by DHE and ECDHE, especially at scale. Modern firewalls often have hardware acceleration for RSA operations.

Reference:
Palo Alto Networks documentation and whitepapers on decryption performance consistently highlight that enabling Perfect Forward Secrecy (PFS), which uses ephemeral key exchanges like DHE and ECDHE, will increase the firewall's CPU utilization and reduce the maximum decryption throughput compared to using non-ephemeral methods like RSA key exchange.

C. SMS
D. User certificate
E. One-time password

Explanation:
The Palo Alto Networks firewall supports several methods for multi-factor authentication (MFA) to enhance the security of administrative access (WebUI, SSH, etc.) and, in some cases, user-based policies. The key is that the MFA method must be integrated and validated by an external authentication server (like a RADIUS server) that the firewall can communicate with.

C. SMS:
This is a common MFA method. The firewall itself doesn't send the SMS. Instead, it forwards the authentication request to a RADIUS server, which is integrated with an SMS gateway service (e.g., Duo, Azure MFA). The server handles sending the code to the user's phone, validating the code entered by the user, and then sending an accept/reject response back to the firewall.

D. User certificate:
User certificates are a strong form of authentication based on public key infrastructure (PKI). The firewall can be configured to require a valid, trusted user certificate to be presented by the client (e.g., the administrator's browser) in addition to a username and password. This constitutes two factors: "something you have" (the private key of the certificate) and "something you know" (the password).

E. One-time password (OTP):
This is a standard and widely supported MFA factor. The firewall uses an authentication server (like RADIUS) that supports time-based one-time passwords (TOTP) or HMAC-based one-time passwords (HOTP). The user has an authenticator app (like Google Authenticator, Microsoft Authenticator, or a hardware token) that generates the code, which the authentication server validates.

Why the other options are incorrect:
A. Voice:
While some advanced MFA providers might offer a voice call-back feature as part of their service, this is not a standard, directly configurable MFA method on the firewall itself. The firewall's authentication mechanism does not have a built-in component to initiate and validate voice calls. The primary communication is with an authentication server using protocols like RADIUS.

B. Fingerprint:
Biometric authentication like a fingerprint is a form of "something you are." The firewall's operating system (PAN-OS) does not have built-in support for biometric readers or the software to validate fingerprints. This factor cannot be used directly to authenticate to the firewall's management interface.

Reference:
The Palo Alto Networks Administrator's Guide section on "Multi-Factor Authentication" explains that the firewall relies on external authentication servers (e.g., RADIUS) to perform the actual validation of the second factor. The supported methods are those that these standard servers can process, such as OTP, SMS via a gateway, and certificate-based authentication.

C. Use ECDSA instead of RSA for traffic that isn't sensitive or high-priority.

Explanation:

Why ECDSA Over RSA?
1.Performance Impact:
ECDSA (Elliptic Curve Cryptography) is less CPU-intensive than RSA for decryption, especially for bulk traffic.
RSA relies on large prime numbers, requiring more computational power for key exchanges and signing operations.
Switching non-sensitive traffic to ECDSA reduces decryption overhead while maintaining security.
2.Resource Optimization:
The firewall is near capacity, so optimizing decryption efficiency is critical.
ECDSA provides comparable security to RSA with shorter key lengths (e.g., 256-bit ECDSA ≈ 3072-bit RSA)

. Why Not the Other Options?
A. Use RSA
Increases load (RSA is more resource-intensive than ECDSA).
B. Highest TLS version
TLS 1.3 improves security but doesn’t reduce decryption load (may even increase it).
D. SSL Forward Proxy
Irrelevant—this is for outbound decryption, not reducing resource usage.

Additional Optimization Tips:
Exclude low-risk traffic from decryption (e.g., public websites).
Use Session Timeouts to limit long-lived decrypted sessions.
Monitor Decryption Profiles to fine-tune policies.

Reference:
Palo Alto Networks Decryption Best Practices:
"ECDSA is recommended for reducing CPU load during decryption, particularly for non-critical traffic."

B. show routing route type service-route

Explanation:
When certain services (like Dynamic Updates, WildFire, or URL Filtering) are not working, the issue often lies in service route configuration. These routes determine how the management plane reaches external services.

To verify that service routes are correctly installed and active, use:
bash show routing route type service-route

This command displays:
The destination IPs for services
The interface and next-hop used
Whether the route is active
📚 Reference:
Palo Alto Networks – Service Route Configuration

❌ Why Other Options Are Wrong:
A & D. debug dataplane internal vif route:
These are low-level dataplane diagnostics — not relevant to management plane service routes.
C. show routing route type management:
Displays routes for management traffic — not service-specific routes.

A. External zones with the virtual systems added.
D. Add a route with next hop next-vr by using the VR configured in the virtual system
E. Ensure the virtual systems are visible to one another.

Explanation:
For virtual systems (vSys) on a Palo Alto Networks firewall to communicate with each other, especially when separate virtual routers (VRs) are used for each vSys, the configuration must facilitate proper routing and security policy enforcement. The key aspects to focus on include:
A. External zones with the virtual systems added:
External zones are special types of zones that are used to facilitate traffic flow between virtual systems within the same physical firewall. By adding virtual systems to an external zone, you enable them to communicate with each other, effectively bypassing the need for traffic to exit and re-enter the firewall.
D. Add a route with next hop next-vr by using the VR configured in the virtual system:
When using separate VRs for each vSys, it's essential to configure inter-VR routing. This is done by adding routes in each VR with the next hop set to 'next-vr', specifying the VR of the destination vSys. This setup enables traffic to be routed from one virtual system's VR to another, facilitating communication between them.
E. Ensure the virtual systems are visible to one another:
Visibility between virtual systems is a prerequisite for inter-vSys communication. This involves configuring the virtual systems in a way that they are aware of each other's existence. This is typically managed in the vSys settings, where you can specify which virtual systems can communicate with each other.
By focusing on these configuration details, the network security engineer can ensure that the virtual systems can communicate effectively, maintaining the necessary isolation while allowing the required traffic flow.

A. Set DNS and Palo Alto Networks Services to use the ethernet1/1 source interface.

Explanation:

Why This Option?
1.Service Route Configuration Purpose:
Determines which interface is used for outbound management traffic (e.g., DNS, updates, license checks).
By default, the MGT interface is used, but this can be overridden to use a data plane interface (e.g., ethernet1/1).
2.Key Requirements:
Dynamic updates (e.g., threat updates, PAN-DB URL filtering) require internet access.
The edge router-connected interface (ethernet1/1) is the logical choice for internet-bound traffic.
3.Configuration Steps:
Navigate to: Setup > Services > Service Route Configuration.
Set DNS and Palo Alto Networks Services to use ethernet1/1 as the source interface.

Why Not Other Options?
B (ethernet1/2)
Visualization network likely lacks internet access.
C/D (MGT)
Defeats the goal of using a data plane interface for updates.
D (DDNS)
Dynamic DNS is irrelevant for threat/update traffic.

Reference:
Palo Alto Admin Guide (Service Routes):
"Service routes allow dynamic updates to use data plane interfaces for internet access."