PCNSE Palo Alto Networks Certified Security Engineer (PCNSE) PAN-OS 10.2 Question and Answers

The firewall can use three multi-factor authentication methods to authenticate access to the firewall: SMS, user certificate, and one-time password. These methods can be used in combination with other authentication factors, such as username and password, to provide stronger security for accessing the firewall web interface or CLI. The firewall can integrate with various MFA vendors that support these methods through RADIUS or SAML protocols5. Voice and fingerprint are not supported by the firewall as MFA methods. References: MFA Vendor Support, PCNSE Study Guide (page 48)

When configuring Quality of Service (QoS) policies, particularly for traffic going to or from specific IP addresses and involving NAT, it's important to base the rule on how the firewall processes the traffic. For QoS, the firewall evaluates traffic using pre-NAT IP addresses and zones because QoS policies typically need to be applied before the NAT action occurs. This is especially true for inbound traffic, where the goal is to limit bandwidth before the destination IP is translated.

The correct combination for a QoS rule in this scenario, where the aim is to limit bandwidth for downloads from a specific server (implying inbound traffic to the server), would be:

D. Pre-NAT source IP address Pre-NAT source zone:

• Pre-NAT source IP address: This refers to the original IP address of the client or source device before any NAT rules are applied. Since QoS policies are evaluated before NAT, using the pre-NAT IP address ensures that the policy applies to the correct traffic.
• Pre-NAT source zone: This is the zone associated with the source interface before NAT takes place. Using the pre-NAT zone ensures that the QoS policy is applied to traffic as it enters the firewall, before any translations or routing decisions are made.

By configuring the QoS rule with pre-NAT information, the firewall can accurately apply bandwidth limitations to the intended traffic, ensuring efficient use of network resources and mitigating the impact of large file downloads from the specified server.

For detailed guidelines on configuring QoS policies, refer to the Palo Alto Networks documentation, which provides comprehensive instructions and best practices for managing bandwidth and traffic priorities on the network.

The cause of the unsecured website warnings is that the forward trust certificate has not been signed by the self-signed root CA certificate. The forward trust certificate is used by the firewall to generate a copy of the server certificate for outbound SSL decryption (SSL Forward Proxy). The firewall signs the copy with the forward trust certificate and presents it to the client. The client then verifies the signature using the public key of the CA that issued the forward trust certificate. If the client does not trust the CA, it will display a warning message. Therefore, the forward trust certificate must be signed by a CA that is trusted by the client. In this case, the administrator has installed the self-signed root CA certificate in all client systems, so this CA should be used to sign the forward trust certificate. However, as shown in the screenshot, the forward trust certificate has a different issuer than the self-signed root CA certificate, which means it has not been signed by it. This causes the client to reject the signature and show a warning message. To fix this issue, the administrator should generate a new forward trust certificate and sign it with the self-signed root CA certificate12. References: Keys and Certificates for Decryption Policies, How to Configure SSL Decryption

• A and D are the best practice deployment modes for the firewall if the company wants to add threat prevention to the network without redesigning the network routing. This is because these modes allow the firewall to act as a transparent device that does not affect the existing network topology or routing1.
• A: VirtualWire mode allows the firewall to be inserted into any existing network segment without changing the IP addressing or routing of that segment2. The firewall inspects traffic between two interfaces that are configured as a pair, called a virtual wire. The firewall applies security policies to the traffic and forwards it to the same interface from which it was received2.
• D: Layer 2 mode allows the firewall to act as a switch that forwards traffic based on MAC addresses3. The firewall inspects traffic between interfaces that are configured as Layer 2 interfaces and belong to the same VLAN. The firewall applies security policies to the traffic and forwards it to the appropriate interface based on the MAC address table3.

Verified References:

• 1: https://www.garlandtechnology.com/blog/whats-your-palo-alto-ngfw-deployment-plan
• 2: https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-admin/networking/configure-interfaces/virtual-wire.html
• 3: https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-admin/networking/configure-interfaces/layer-2.html

A: https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-web-interface-help/network/network-virtual-routers/more-runtime-stats-for-a-logical-router#id5628a5e4-e908-457e-a2fd-270a476ab752

D: https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-cli-quick-start/cli-cheat-sheets/cli-cheat-sheet-networking

To generate email alerts when decryption rules are changed in a Palo Alto Networks firewall, you would configure email log forwarding based on specific system logs that capture changes to decryption policies. This is done by setting up log forwarding profiles with filters that match events related to decryption rule modifications. These profiles are then applied to the relevant log types within the firewall's log settings.

To specifically monitor for changes to decryption rules, you would navigate to the Device > Log Settings section of the firewall's web interface. Here, you can configure log forwarding for system logs, which capture configuration changes among other system-level events. By creating a filter that looks for logs associated with decryption rule changes, and associating this filter with an email server profile, the firewall can automatically send out email alerts whenever a decryption rule is modified.

This setup ensures that the security team is promptly notified of any changes to the decryption policies, allowing for quick review and action if the changes were unauthorized or unintended. It is an essential part of maintaining the security posture of the network and ensuring compliance with organizational policies on encrypted traffic inspection.

The timer that determines the frequency between packets sent to verify that the HA functionality on the other HA firewall is operational is the Hello Interval. The Hello Interval is the interval in milliseconds between hello packets that are sent to check the HA status of the peer firewall. The default value for the Hello Interval is 8000 ms for all platforms, and the range is 8000-60000 ms. If the firewall does not receive a hello packet from its peer within the specified interval, it will declare the peer as failed and initiate a failover12. References: HA Timers, Layer 3 High Availability with Optimal Failover Times Best Practices

How to Configure Ping Interval/Timeout Settings ... - Palo Alto Networks

When managing firewalls with Panorama, configurations can be pushed from Panorama templates to managed firewalls. However, there are scenarios where specific settings need to be overridden on the local firewall level due to unique requirements or exceptions.

B. The modification will not be visible in Panorama:

• When an override is made directly on the firewall, this change is not automatically reflected back in Panorama's templates or device groups. The local configuration on the firewall will take precedence over the Panorama pushed configuration for the overridden settings, but these local changes will not be visible in the Panorama interface. This means that while Panorama maintains central control and visibility over the bulk of the configuration, it does not have visibility into local overrides made directly on the firewalls.

This distinction is crucial for auditors and administrators to understand, as it impacts how configurations are managed and synchronized between Panorama and the individual firewalls. Local overrides provide flexibility but require careful management to ensure consistency and compliance with security policies.

When sizing a decryption firewall deployment, two factors that should be considered are the encryption algorithm and the TLS protocol version. These factors affect the amount of resources and processing power that the firewall needs to decrypt and inspect SSL/TLS traffic.

The encryption algorithm is the method that the server and the client use to encrypt and decrypt the data exchanged in an SSL/TLS session. Different encryption algorithms have different levels of security and performance. For example, AES is a symmetric encryption algorithm that is faster and more efficient than RSA, which is an asymmetric encryption algorithm. However, RSA is more secure than AES because it uses public and private keys to encrypt and decrypt data, while AES uses a single shared key. The firewall must support the encryption algorithms that are used by the servers and clients that it decrypts, and it must have enough CPU and memory resources to handle the decryption workload12.

The TLS protocol version is the standard that defines how the server and the client establish and maintain an SSL/TLS session. Different TLS protocol versions have different features and requirements for encryption algorithms, cipher suites, certificates, handshake messages, etc. For example, TLS 1.3 is the latest and most secure version of TLS, which supports only strong encryption algorithms and cipher suites, such as AES-GCM and ChaCha20-Poly1305, and requires elliptic curve certificates. The firewall must support the TLS protocol versions that are used by the servers and clients that it decrypts, and it must have enough hardware acceleration resources to handle the decryption speed34.

The number of security zones in decryption policies and the number of blocked sessions are not relevant factors for sizing a decryption firewall deployment. The number of security zones in decryption policies only affects how the firewall matches traffic to decryption rules based on source and destination zones, but it does not affect the decryption performance or resource consumption. The number of blocked sessions only indicates how many sessions are denied by the firewall based on security policy or decryption policy rules, but it does not affect the decryption capacity or throughput56.

References: Encryption Algorithms, TLS Protocol Versions, Decryption Policy, PCNSE Study Guide (page 60)

Palo Alto Networks recommends following a specific upgrade path when upgrading PAN-OS to ensure compatibility and minimize the risk of issues. The recommended path involves sequential upgrades through major releases.

B. The detailed upgrade path from PAN-OS 10.1 to 11.0.x involves:

• First, upgrading to the latest preferred maintenance release of the current PAN-OS version (10.1) to ensure that all the latest fixes and improvements are applied.
• Next, upgrading to the base version of the next major release (PAN-OS 10.2.0), followed by upgrading to the latest preferred maintenance release of PAN-OS 10.2. This step ensures that the firewall is on a stable and supported version before proceeding to the next major release.
• Finally, upgrading to the base version of PAN-OS 11.0 (11.0.0), followed by the desired PAN-OS 11.0.x version. This step completes the upgrade to the new major version, providing access to new features and improvements, such as TLSv1.3 support for management access.

This sequential upgrade path is designed to ensure a smooth transition between major versions, maintaining system stability and security.

PAN-OS can decrypt and inspect SSL inbound and outbound connections going through the firewall. SSL decryption can occur on interfaces in virtual wire, Layer 2 or Layer 3 mode https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClmyCAC

https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/zone-protection-and-dos-protection/zone-defense/packet-buffer-protection

The type of policy in Palo Alto Networks firewalls that can use Device-ID as a match condition is QoS. This is because Device-ID is a feature that allows the firewall to identify and classify devices on the network based on their characteristics, such as vendor, model, OS, and role1. QoS policies are used to allocate bandwidth and prioritize traffic based on various criteria, such as application, user, source, destination, and device2. By using Device-ID as a match condition in QoS policies, the firewall can apply different QoS actions to different types of devices, such as IoT devices, laptops, smartphones, etc3. This can help optimize the network performance and ensure the quality of service for critical applications and devices.

https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/user-id/map-ip-addresses-to-users/configure-user-id-to-monitor-syslog-senders-for-user-mapping#iddb1a7744-17c6-4900-a2cb-5f3511fef60f

The best description of the Cluster Synchronization Timeout (min) is the maximum time that the local firewall waits before going to Active state when another cluster member is preventing the cluster from fully synchronizing. This is a parameter that can be configured in an HA cluster, which is a group of firewalls that share session state and provide high availability and scalability. The Cluster Synchronization Timeout (min) determines how long the local firewall will wait for the cluster to reach a stable state before it decides to become Active and process traffic. A stable state means that all cluster members are either Active or Passive, and have synchronized their sessions with each other. If there is another cluster member that is in an unknown or unstable state, such as Initializing, Non-functional, or Suspended, then it may prevent the cluster from fully synchronizing and cause a delay in traffic processing. The Cluster Synchronization Timeout (min) can be set to a value between 0 and 30 minutes, with a default of 0. If it is set to 0, then the local firewall will not wait for any other cluster member and will immediately go to Active state. If it is set to a positive value, then the local firewall will wait for that amount of time before going to Active state, unless the cluster reaches a stable state earlier12. References: Configure HA Clustering, PCNSE Study Guide (page 53)

How to Set Session, TCP, and UDP Timeout Values - Palo Alto Networks ...

When a URL matches multiple categories, the category chosen is the one that has the most severe action defined below (block being most severe and allow least severe).

1 block

2 override

3 continue

4 alert

5 allow

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClsmCAC

A syslog listener is the best choice for deploying User-ID to ensure maximum coverage in an environment with multiple forms of authentication. A syslog listener is a feature that enables the firewall or Panorama to receive syslog messages from other systems and parse them for IP address-to-username mappings. A syslog listener can collect user mapping information from a variety of sources, such as network access control systems, domain controllers, MDM solutions, VPN gateways, wireless controllers, proxies, and more2. A syslog listener can also support multiple platforms and operating systems, such as Windows, Linux, macOS, iOS, Android, etc3. Therefore, a syslog listener can provide a comprehensive and flexible solution for User-ID deployment in a large-scale network. References: Configure a Syslog Listener for User Mapping, User-ID Agent Deployment Guide, PCNSE Study Guide (page 48)

When implementing an application override in a Palo Alto Networks firewall, the primary goal is to explicitly define how specific traffic is identified and processed by the firewall, bypassing the regular App-ID process. This is particularly useful for traffic that might be misidentified by App-ID or for applications that require special handling for performance reasons.

To successfully implement application override, the following items must be configured:

B. Application override policy rule:This is a specialized policy rule that you create to specify the criteria for the traffic you want to override. In this rule, you define the source and destination zones, addresses, and ports. Instead of relying on the App-ID engine to identify the application, the firewall uses the criteria defined in the application override policy to classify the traffic.

C. Security policy rule:After defining an application override policy, you must also configure a security policy rule to allow the overridden traffic through the firewall. This rule specifies the action (allow, deny, drop, etc.) for the traffic that matches the application override policy. It's essential to ensure that the security policy rule matches the traffic defined in the application override policy to ensure that the intended traffic is allowed through the firewall.

For detailed guidance on configuring application override and the necessary security policies, refer to the official Palo Alto Networks documentation. This resource provides step-by-step instructions and best practices for effectively managing traffic using application overrides.

SSL/TLS profile is only the TLS versions, not ciphers. Decryption Profile is for SSL Inbound and Forward Proxy applications, not mgmt of the PANW Firewall. There's also KB articles to strengthen SSH, but I couldn't find any for HTTPS, on the mgmt interface: https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA14u0000004OOQCA2 &lang=en_US%E2%80%A9

https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-admin/high-availability/ha-concepts/ha-timers

Recommended: Use for typical failover timer settings. Unless you’re sure that you need different settings, the best practice is to use the Recommended settings.

Aggressive: Use for faster failover timer settings.

Advanced: Allows you to customize the values to suit your network requirement for each of the following timers:

https://live.paloaltonetworks.com/t5/panorama-discussions/panorama-force-template-value-option/td-p/496620 "- Force Template Value will as the name suggest remove any local configuratio and apply the value define the panorama template. But this is valid only for overlapping configuration" "You need to be careful, what is actually defined in the template. For example - if you decide to enable HA in the template, but after that you decide to not push it with template and just disable it again (remove the check from the "Enable HA" checkbox). This still will be part of the template, because now your template is explicitely defining HA disabled. If you made a change in the template, and later decide that you don't want to control this setting with template, you need to revert the config by clicking the green bar next to the changed value"

For HIP match logs to be visible on the data center firewall, the following conditions must be met:

• HIP profiles added to security rules: HIP profiles must be applied to security rules on the data center firewall to enforce access restrictions based on the received HIP reports. If the HIP profiles are not associated with the security rules, the firewall will not evaluate traffic against these profiles, and consequently, no HIP match logs will be generated.
• User-ID enabled on the incoming zone: User-ID must be enabled on the zone where the users are located in the data center firewall. The User-ID feature is responsible for mapping IP addresses to user names, which is critical for applying policies based on user identity and, by extension, for HIP-based policy enforcement.

The other options (A and D) are related to logging and log forwarding but would not directly impact the generation or visibility of HIP match logs on the data center firewall itself.

https://docs.paloaltonetworks.com/compatibility-matrix/ipv6-support-by-feature/ipv6- support-by-feature-table

In the second image, VW ports mentioned are 1/5 and 1/7. Hence it can not be a part of any other routing. So if any traffic coming as ingress from 1/7, it has to go out via 1/5.

The egress interface for the traffic with ingress interface ethernet1/7, source 192.168.111.3, and destination 10.46.41.113 will be ethernet1/5. This is because the traffic will match the virtual wire with interfaces ethernet1/5 and ethernet1/7, which is configured to allow VLAN-tagged traffic with tags 10 and 201. The traffic will also match the security policy rule that allows traffic from zone Trust to zone Untrust, which are assigned to ethernet1/7 and ethernet1/5 respectively2. Therefore, the traffic will be forwarded to the same interface from which it was received, which is ethernet1/53.

In a High Availability (HA) configuration, particularly in an active-passive setup, it's crucial that the passive unit is kept up to date with the current state of the active unit. This ensures a seamless transition in the event of a failover. The HA4 interface is dedicated to this synchronization task.

D. Perform synchronization of sessions, forwarding tables, and IPSec security associations between firewalls in an HA pair:

• The HA4 interface is responsible for the synchronization of critical stateful information between the active and passive units in an HA pair. This includes session information, ensuring that the passive unit can continue existing sessions without interruption if it needs to become active.
• In addition to session information, HA4 also synchronizes forwarding tables, which contain information on how to route packets, and IPSec security associations, which are necessary for maintaining secure VPN tunnels.

This synchronization ensures that both units in an HA pair have identical information regarding the current state of the network, sessions, and security associations, enabling a smooth and immediate transition to the passive unit in case the active unit fails.

When building Security rules in a Device Group that need to allow traffic to specific users and groups defined in Active Directory, it's essential to have user and group information available in Panorama to select these entities for the rules.

D. A master device with Group Mapping configured must be set in the device group where the Security rules are configured:

• The concept of a "master device" in Panorama refers to a specific firewall that is designated to provide certain settings or information, such as user and group mappings from Active Directory, to Panorama. This information can then be used across other firewalls within the same device group.
• By configuring Group Mapping on a master device, Panorama can leverage this information to populate user and group objects. These objects can then be used in Security rules within the device group, allowing for the creation of policies that are based on user identity and group membership, as defined in Active Directory.
• This setup ensures that Panorama has the necessary context to apply user- and group-based policies accurately across the managed firewalls, facilitating centralized management and consistency in policy enforcement.

Hover over an attribute in the table below the chart and click the arrow icon to the right of the attribute. https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-admin/monitoring/use-the-application-command-center/interact-with-the-acc#id5cc39dae-04cf-4936-9916-1a4b0f3179b9

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000PNGFCA4

https://docs.paloaltonetworks.com/best-practices/10-2/data-center-best-practices/data-center-best-practice-security-policy/how-to-create-data-center-best-practice-security-profiles/create-the-data-center-best-practice-anti-spyware-profile

The Palo Alto Networks Best Practices for Anti-Spyware Profiles recommend enabling single-packet captures (PCAP) for medium, high, and critical severity threats. This allows for capturing the first packet of the malicious traffic for further analysis and investigation. PCAP should not be enabled for low and informational severity threats, as they generate a relatively high volume of traffic and are not particularly useful compared to potential threats2. References: Create the Data Center Best Practice Anti-Spyware Profile, Security Profile: Anti-Spyware, PCNSE Study Guide (page 57)

https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-web-interface-help/panorama-web-interface/panorama-device-deployment/manage-software-and-content-updates

https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-web-interface-help/panorama-web-interface/panorama-device-deployment/panorama-dynamic-updates-revert-content

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClhwCAC

https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-networking-admin/nat/source-nat- and-destination-nat/source-nat

'Implicitly Uses' has web-browsing listed. This means that if you allow facebook-posting, that it will also be allowing the web-browsing application implicitly.. In our case, we dont know which APP the question referes too but 'Implicitly means already uses HTTP.

ttps://www.kareemccie.com/2021/05/palo-alto-firewall-packet-flow.html

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClGJCA0

The engineer should adjust the TCP maximum segment size (MSS) value on ethernet1/1 to remedy this problem. This is because the MTU on an upstream router interface is set to 1400 bytes, which is causing the return traffic from the web servers to not reach the users behind the firewall. By adjusting the TCP MSS value, the engineer can ensure that the return traffic is able to reach the users without any issues.

The TCP MSS is the maximum amount of data that can be transmitted in a single TCP segment, excluding the TCP and IP headers. The TCP MSS is usually derived from the MTU of the underlying network, which is the maximum packet size that can be transmitted without fragmentation. For example, if the MTU is 1500 bytes, which is the default value for ethernet interfaces, then the TCP MSS is 1460 bytes (1500 - 20 bytes for IP header - 20 bytes for TCP header). However, if there are intermediate devices or networks that have a lower MTU than the end-to-end path, then the TCP MSS may need to be adjusted accordingly to avoid packet loss or fragmentation1.

In this case, the firewall has an MTU of 1500 bytes on ethernet1/1, which is connected to a WAN link. However, an upstream router has an MTU of 1400 bytes on its interface, which means that any packet larger than 1400 bytes will be either dropped or fragmented by the router. This can cause problems for the return traffic from the web servers, which may have a TCP MSS of 1460 bytes or higher, depending on their MTU settings. If these packets have the Don’t Fragment (DF) bit set in their IP header, which is common for TCP packets, then they will be dropped by the router and never reach the firewall or the users behind it. If they do not have the DF bit set, then they will be fragmented by the router and reassembled by the firewall, which can cause performance degradation and overhead2.

To avoid these problems, the engineer should adjust the TCP MSS value on ethernet1/1 to match or be lower than the MTU of the upstream router. This can be done by using the CLI command set network interface ethernet ethernet1/1 tcp-mss , where is an integer between 64 and 15003. For example, if the engineer sets the TCP MSS value to 1360 bytes (1400 - 20 - 20), then this will ensure that any TCP packet sent or received by ethernet1/1 will not exceed 1400 bytes in total size, and thus will not be dropped or fragmented by the router. This will allow the return traffic from the web servers to reach the users behind the firewall without any issues4.

References: TCP Maximum Segment Size (MSS), Configure Session Settings, TCP MSS Adjustments, PCNSE Study Guide (page 59)

Regardless of whether you generate Forward Trust certificates from your Enterprise Root CA or use a self-signed certificate generated on the firewall, generate a separate subordinate Forward Trust CA certificate for each firewall. The flexibility of using separate subordinate CAs enables you to revoke one certificate when you decommission a device (or device pair) without affecting the rest of the deployment and reduces the impact in any situation in which you need to revoke a certificate. Separate Forward Trust CAs on each firewall also helps troubleshoot issues because the CA error message the user sees includes information about the firewall the traffic is traversing. If you use the same Forward Trust CA on every firewall, you lose the granularity of that information.

https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/decryption/configure-ssl-forward-proxy

 The correct packet-flow sequence is C. PBF > Static route > Security policy enforcement. This sequence describes the order of operations that the firewall performs when processing a packet. PBF stands for Policy-Based Forwarding, which is a feature that allows the firewall to override the routing table and forward traffic based on the source and destination addresses, application, user, or service. PBF is evaluated before the static route lookup, which is the default method of forwarding traffic based on the destination address and the longest prefix match. Security policy enforcement is the stage where the firewall applies the security policy rules to allow or block traffic based on various criteria, such as zone, address, port, user, application, etc12. References: Policy-Based Forwarding, Packet Flow Sequence in PAN-OS

• B is the best choice for an SSL Forward Untrust certificate because a self-signed certificate generated on the firewall is not trusted by any client browsers by default1. This means that if the firewall observes an invalid or untrusted security certificate from the server, it will present the self-signed certificate to the client, which will trigger an untrusted certificate warning2. This way, the security admin can ensure that users are aware of any potential risks when accessing HTTPS sites with untrusted certificates.
• A web server certificate signed by the organization’s PKI (A) or a subordinate Certificate Authority certificate signed by the organization’s PKI © are not good choices for an SSL Forward Untrust certificate because they are trusted by the client browsers that have the organization’s root CA installed1. This means that if the firewall observes an invalid or untrusted security certificate from the server, it will present the web server or subordinate CA certificate to the client, which will not trigger an untrusted certificate warning2. This way, the security admin cannot ensure that users are aware of any potential risks when accessing HTTPS sites with untrusted certificates.
• A web server certificate signed by an external Certificate Authority (D) is not a good choice for an SSL Forward Untrust certificate because it is trusted by most client browsers that have the external CA in their trust store1. This means that if the firewall observes an invalid or untrusted security certificate from the server, it will present the web server certificate to the client, which will not trigger an untrusted certificate warning2. This way, the security admin cannot ensure that users are aware of any potential risks when accessing HTTPS sites with untrusted certificates.

Verified References:

• 1: How to Configure SSL Decryption - Palo Alto Networks Knowledge Base
• 2: How to Implement and Test SSL Decryption - Palo Alto Networks Knowledge Base

Policy-Based Forwarding (PBF) on Palo Alto Networks firewalls allows administrators to define forwarding decisions based on criteria other than the destination IP address, such as the application, source address, or user. It can address scenarios like:

A. Routing FTP to a backup ISP link to save bandwidth on the primary ISP link: PBF can be configured to identify FTP traffic and route it through a different ISP, preserving bandwidth on the primary link for other critical applications.

B. Providing application connectivity when the primary circuit fails: PBF can be used for failover purposes, directing traffic to an alternate path if the primary connection goes down, ensuring continuous application availability.

PBF is not designed to bypass Layer 7 inspection or forward traffic based solely on source port, as these tasks are managed through different mechanisms within the firewall's operating system.

If an administrator wants to apply QoS to traffic based on source, they must specify the post-NAT source address in a QoS policy rule. This is because QoS is enforced on traffic as it egresses the firewall, and the firewall applies NAT rules before QoS rules. Therefore, the firewall will match the QoS policy rule based on the translated source address, not the original source address. If the administrator uses the pre-NAT source address in the QoS policy rule, the firewall will not be able to identify the traffic correctly and apply the desired QoS treatment. References:

• QoS Policy
• Configure QoS

The Advanced Routing Engine in Palo Alto Networks firewalls enhances the capabilities of routing functionalities, allowing for more complex and robust routing configurations. To enable the Advanced Routing Engine on a Palo Alto Networks firewall, an administrator needs to navigate to the Network tab, select Virtual Routers, and then access the settings for the specific virtual router they wish to configure. Within the Router Settings under the General tab, there's an option to enable Advanced Routing features. After enabling this option, the administrator must commit the changes and perform a system reboot for the changes to take effect. This process allows the firewall to utilize advanced routing protocols and features, enhancing its ability to manage and route traffic more efficiently across different network segments.

https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/policy/use-address-object-to-represent-ip-addresses/address-objects

https://live.paloaltonetworks.com/t5/blogs/what-is-application-dependency/ba-p/344330

To create an application-based Security policy rule to allow Evernote, the administrator only needs to add the Evernote application to the Security policy rule. The Evernote application is a predefined App-ID that identifies the traffic generated by the Evernote client or web interface. The Evernote application implicitly uses SSL and web browsing as dependencies, which means that the firewall automatically allows these applications when the Evernote application is allowed. Therefore, there is no need to add HTTP, SSL, or web browsing applications to the same Security policy rule. Adding these applications would broaden the scope of the rule and potentially allow unwanted traffic12. References: App-ID Overview, Create a Security Policy Rule

The compare option for a specific rule in the New App Viewer under Policy Optimizer allows an administrator to compare the applications configured in the rule with the applications seen from traffic matching the same rule. This helps the administrator to identify any new applications that are not explicitly defined in the rule, but are implicitly allowed by the firewall based on the dependencies of the configured applications. The compare option also shows the usage statistics and risk levels of the applications, and provides suggestions for optimizing the rule by adding, removing, or replacing applications12. References: New App Viewer (Policy Optimizer), PCNSE Study Guide (page 47)

Why use Security Policy Optimizer and what are the benefits?

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClEiCAK

https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-web-interface-help/network/network-network-profiles/network-network-profiles-monitor.html

https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/decryption/configure-ssl-forward-proxy

https://live.paloaltonetworks.com/t5/general-topics/wildfire-submission-entries-with-severity-high-showing-action/td-p/143516

Decryption Mirror is a feature that allows a Palo Alto Networks firewall to send a copy of decrypted traffic to an external security device or tool for further analysis. The potential risk associated with Decryption Mirror is that if the firewall administrator's credentials are compromised, a malicious user could potentially access sensitive decrypted information. Hence, it's advised to be cautious and ensure proper handling of this feature.

Additionally, laws and regulations regarding the decryption, storage, inspection, and use of SSL/TLS encrypted traffic vary by country and industry. It is crucial to ensure compliance with relevant laws and best practices when using Decryption Mirror. This often requires consultation with corporate legal counsel to understand the implications and ensure that the use of such features does not violate privacy laws or regulatory requirements.

The need for administrative consent and the legal implications of using Decryption Mirror features are outlined in Palo Alto Networks' "PAN-OS® Administrator’s Guide" and best practice documentation. It is not specifically required to have a tap interface to use Decryption Mirror, which eliminates option A. Option C is incorrect because it is not just management consent but legal compliance that needs to be considered.