PCNSE Questions and Answers

https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-networking-admin/nat/nat-configuration-examples/destination-nat-exampleone-to-one-mapping

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.

The best decryption best practice that the administrator should consider is A: Consider the local, legal, and regulatory implications and how they affect which traffic can be decrypted. This is because decryption involves intercepting and inspecting encrypted traffic, which may raise privacy and compliance issues depending on the jurisdiction and the type of traffic1. Therefore, the administrator should be aware of the local, legal, and regulatory implications and how they affect which traffic can be decrypted, and follow the appropriate guidelines and policies to ensure that decryption is done in a lawful and ethical manner1.

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.

External zones are a unique zone type on Palo Alto Networks firewalls that facilitate the movement of traffic between virtual systems on the same physical appliance. These zones are required when multiple virtual systems (vsys) are configured on a single firewall and there is a need to allow inter-vsys traffic without the need for the traffic to leave the firewall and re-enter. An external zone is associated with a specific virtual system and enables traffic to pass from one virtual system to another securely, thereby simplifying traffic management and reducing the need for additional physical interfaces or external routing to handle inter-vsys communication.

Palo Alto Networks Device Telemetry data, collected from firewalls with a device certificate installed, is stored on Palo Alto Networks Update Servers. This telemetry data includes information about threats, device health, and other operational metrics that are crucial for the continuous improvement of security services and threat intelligence. The collected data is anonymized and securely transmitted to Palo Alto Networks, where it is used to enhance the overall effectiveness of threat identification and prevention capabilities across all deployed devices. This collaborative approach helps in keeping the security ecosystem updated and resilient against emerging threats.

For a network security administrator to authenticate and identify a user with a new BYOD-type device that is not joined to the corporate domain, the most effective method is to use an Authentication policy targeting users not yet identified by the system.

A. an Authentication policy with 'unknown' selected in the Source User field:

• An Authentication policy allows the firewall to challenge unidentified users for credentials. By selecting 'unknown' in the Source User field, the policy targets users who have not yet been identified by the firewall, which would include users on new BYOD devices not joined to the domain.
• Once the user provides valid credentials, the firewall can authenticate the user and map their identity to subsequent sessions, enabling the application of user-based policy rules and monitoring.

This approach ensures that new and unknown devices can be properly authenticated and identified without compromising security or requiring the device to be part of the corporate domain.

Based on the snippet of the WildFire submission log provided, it appears that the end user was able to successfully download a file. The key indicator here is that the final action for the web-browsing application and the flash file is set to “allow.” This means that despite any alerts or other actions taken earlier in the process, the ultimate decision was to allow the file to be downloaded.

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://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000PP3ICAW

The CLI command "show system state filter-pretty sys.sl.p8.phy" is used to display detailed physical layer information, which would include the physical media connected to a specific interface such as ethernet1/8. This command is designed to filter the output to show relevant physical layer information for the specified interface.For more information on Palo Alto Networks CLI commands and their outputs, refer to the "PAN-OS® CLI Reference Guide".

For collecting User-ID user mapping information, the most reliable and commonly used source is directory services, with Microsoft Active Directory being the predominant choice in many organizational environments.

C. Microsoft Active Directory:

• Microsoft Active Directory is a directory service used for user authentication and authorization. It provides a comprehensive database of user accounts, groups, and other objects within an organization's network. Palo Alto Networks firewalls can integrate with Active Directory to obtain real-time user mapping information, which is crucial for implementing security policies based on user identity.
• The integration involves monitoring Active Directory domain controllers for security logs that contain user login events, IP address mappings, and other relevant information. This allows the firewall to accurately and dynamically map user identities to IP addresses, enhancing the granularity and effectiveness of security policies.
• Compared to other sources like Syslog Listener, Microsoft Exchange, or GlobalProtect, Active Directory offers direct and comprehensive insights into user activities and is therefore considered the most reliable source for User-ID user mapping in Palo Alto Networks environments.

• 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

Traffic didnt match any other policies and so landed at the implicit "deny all" policy. If it's deny all, the traffic was dropped before the application could be determined. https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClibCAC

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

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

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

In a situation where Panorama and its managed firewalls lack internet access, updating PAN-OS requires a manual upload of the downloaded PAN-OS images. The process involves:

D. Upload the image to Panorama > Device Deployment > Software menu, and deploy it to the firewalls:

• The engineer first uploads the downloaded PAN-OS images to Panorama. This is done through the "Device Deployment" section, specifically under the "Software" menu. This area of Panorama's interface is designed for managing PAN-OS versions and software updates for the managed devices.
• Once the PAN-OS images are uploaded to Panorama, the engineer can then deploy these images to the firewalls directly from Panorama. This process allows for centralized management of software updates, ensuring that all firewalls can be updated to the latest PAN-OS version in a consistent and controlled manner, even without direct internet access.

This method streamlines the update process for environments with strict security requirements, allowing for the efficient deployment of necessary PAN-OS updates to maintain security and functionality.

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

To enable XML API access to a firewall for automation from a network segment routed through a Layer 3 sub-interface, the most straightforward approach is to use an Interface Management profile.

C. This can be achieved by:

• Configuring an Interface Management profile and enabling HTTPS access on it. This profile defines management services that are permitted on the interface, including HTTPS, which is required for XML API access.
• Applying this Interface Management profile to the desired Layer 3 sub-interface. This action enables HTTPS access (and thus XML API access) on the sub-interface, allowing devices on the connected network segment to communicate with the firewall for automation purposes.

This solution allows for the secure extension of management capabilities to network segments without direct access to the dedicated management interface, facilitating automation and operational efficiency without necessitating changes to existing access configurations.

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

• 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

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

For an application that is currently identified as unknown-tcp and has sessions that often remain idle for long periods, creating a custom application and using an application override rule is the most time-efficient solution.

C. The process involves:

• Creating a custom application in the Palo Alto Networks firewall and configuring it with specific timeouts to accommodate the application's idle session behavior. This step ensures that the firewall does not prematurely close the application's sessions due to inactivity.
• Next, creating an application override rule that references the custom application. This rule directs the firewall to identify traffic matching the rule criteria (such as source, destination, and port information) as the custom application, bypassing the App-ID engine's regular identification process.

This approach allows for the quick implementation of a solution that ensures the application is properly identified in traffic logs without undergoing threat scanning, meeting the requirements for both identification and reporting.

The three authentication types that can be used to authenticate users are:

• A: Local database authentication. This is the authentication type that uses the local user database on the firewall or Panorama to store and verify user credentials1.
• C: Cloud authentication service. This is the authentication type that uses a cloud-based identity provider, such as Okta, PingOne, or PingFederate, to authenticate users and provide SAML assertions to the firewall or Panorama2.
• E: Kerberos single sign-on. This is the authentication type that uses the Kerberos protocol to authenticate users who are logged in to a Windows domain and provide them with seamless access to resources on the firewall or Panorama3.

When the peer device will act as the initiator and none of the peer addresses are known, the administrator can enable Passive Mode to establish the VPN connection. Passive Mode tells the firewall to wait for the peer device to initiate the VPN connection. The other options are incorrect. Option A, setting up certificate authentication, would require the administrator to know the peer device's certificate. Option C, using the Dynamic IP address type, would require the administrator to know the peer device's dynamic IP address. Option D, configuring the peer address as an FQDN, would require the administrator to know the peer device's fully qualified domain name.

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClIGCA0

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

'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.

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClETCA0

A device group is a logical grouping of firewalls that share the same security policy rules. A device group can contain multiple vsys and firewalls, including multi-vsys firewalls. A multi-vsys firewall can have each vsys in a different device group, depending on the desired security policy for each vsys. This allows for granular control and flexibility in managing multi-vsys firewalls with Panorama1. References: Device Group Push to a Multi-VSYS Firewall, Configure Virtual Systems, PCNSE Study Guide (page 50)

The engineer is configuring a DoS Protection profile to defend specific endpoints and resources against malicious activity. A DoS Protection profile is a feature that enables the firewall to detect and prevent denial-of-service (DoS) attacks that attempt to overwhelm network resources or disrupt services. A DoS Protection profile can provide granular defense against targeted flood attacks for specific critical systems that are accessed by users from the internet, such as web servers, DNS servers, or VPN gateways. A DoS Protection profile can be applied to a security policy rule that matches the traffic to and from the protected systems, and can specify the thresholds and actions for different types of flood attacks, such as SYN, UDP, ICMP, or other IP floods12. References: DoS Protection, PCNSE Study Guide (page 58)

To prevent the import from affecting ongoing traffic when you import the configuration of an HA pair into Panorama, you should disable config sync on both firewalls. Config sync is a feature that enables the firewalls in an HA pair to synchronize their configurations and maintain consistency. However, when you import the configuration of an HA pair into Panorama, you want to avoid any changes to the firewall configuration until you verify and commit the imported configuration on Panorama. Therefore, you should disable config sync before importing the configuration, and re-enable it after committing the changes on Panorama12. References: Migrate a Firewall HA Pair to Panorama Management, PCNSE Study Guide (page 50)

https://docs.paloaltonetworks.com/pan-os/11-0/pan-os-admin/virtual-systems/customize-service-routes-for-a-virtual-system/customize-service-routes-to-services-for-virtual-systems

The Exceptions settings allows you to change the response to a specific signature. For example, you can block all packets that match a signature, except for the selected one, which generates an alert. The Exception tab supports filtering functions.

If you not believed, then login the firewall go to Vulnerability > Exceptions and select "Show all signatures". From there you will see all threat information including specific actions.

More detail: https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000Cm4yCAC

The GlobalProtect VPN solution by Palo Alto Networks is designed to provide secure remote access to users. It primarily attempts to establish a VPN tunnel using the IPSec protocol for optimal security and performance. However, in cases where IPSec cannot be used due to network restrictions or other issues, GlobalProtect has a fallback mechanism.

C. It tries to establish a tunnel to the GlobalProtect gateway using SSL/TLS:

• If the GlobalProtect app fails to establish an IPSec tunnel with the GlobalProtect gateway, the default behavior is to fallback to SSL/TLS for tunnel establishment. This ensures that the VPN connection can still be established, maintaining secure remote access for the user even in environments where IPSec is not feasible. SSL/TLS provides a secure tunnel, albeit generally with slightly less efficiency than IPSec.

This fallback mechanism is part of the GlobalProtect app's design to ensure reliability and continuous secure access for remote users under various network conditions.

Set the Action to take when matching a packet:

Forward—Directs the packet to the specified Egress Interface.

Forward to VSYS (On a firewall enabled for multiple virtual systems)—Select the virtual system to which to forward the packet.

Discard—Drops the packet.

No PBF—Excludes packets that match the criteria for source, destination, application, or service defined in the rule. Matching packets use the route table instead of PBF; the firewall uses the route table to exclude the matched traffic from the redirected port.

https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-admin/policy/policy-based-forwarding/create-a-policy-based-forwarding-rule#ideca3cc65-03d7-449d-b47a-90fabee5293c

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

Virtual Desktop Infrastructure (VDI) and Virtual Machine (VM) environments, such as Citrix XenApp and XenDesktop or VMWare Horizon and Vcenter, support access natively through HTML5. You can RDP, VNC, or SSH to these machines through Clientless VPN without requiring additional third-party middleware. In environments that do not include native support for HTML5 or other web application technologies supported by Clientless VPN, you can use third-party vendors, such as Thinfinity, to RDP through Clientless VPN. Reference: https://docs.paloaltonetworks.com/globalprotect/10-1/globalprotect-admin/globalprotect-clientless-vpn/supported-technologies

https://networkwiki.blogspot.com/2017/03/palo-alto-networks-clientless-vpn-and.html

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://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/vpns/set-up-site-to-site-vpn/interpret-vpn-error-messages

The VPN peer on one end is using policy-based VPN. You must configure a Proxy ID on the Palo Alto Networks firewall. https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-admin/vpns/set-up-site-to-site-vpn/interpret-vpn-error-messages.html

When an administrator needs to evaluate recent policy changes that were committed and pushed to a firewall device group in Panorama, the most direct approach is to use the "Preview Changes" feature.

A. Click Preview Changes under Push Scope:

• The "Preview Changes" option is available under the "Push Scope" in Panorama. This feature allows administrators to see a detailed comparison of the changes that are about to be pushed to the managed firewalls or that have been recently pushed. It highlights the differences between the current configuration and the previous one, making it easier to identify exactly what changes were made, including modifications to policies, objects, and other settings.
• This is particularly useful for auditing and verifying that the intended changes match the actual changes being deployed, enhancing transparency and reducing the risk of unintended configuration modifications.

This approach provides a clear and concise way to review configuration changes before and after they are applied, ensuring that policy modifications are intentional and accurately reflect the administrator's objectives.

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClRdCAK

https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/url-filtering/configure-url-filtering

https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/url-filtering/allow-password-access-to-certain-sites#id7e63ce07-8b30-4506-a1e3-5800303954e8

If the DNS response matches the Original Destination Address in the rule, translate the DNS response using the same translation the rule uses. For example, if the rule translates IP address 1.1.1.10 to 192.168.1.10, the firewall rewrites a DNS response of 1.1.1.10 to 192.168.1.10. https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-admin/networking/nat/source-nat-and-destination-nat/destination-nat-dns-rewrite-use-cases#id0d85db1b-05b9-4956-a467-f71d558263bb

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.