NGFW-Engineer Palo Alto Networks Next-Generation Firewall Engineer Question and Answers

The phases of the Palo Alto Networks AI Runtime Security: Network Intercept solution are designed to help identify and protect against potential threats in real time by using AI to detect and prevent malicious activities within the network.

Discovery: Identifying applications, services, and behaviors within the network to understand baseline activity.

Deployment: Implementing the solution into the network and integrating with existing security measures.

Detection: Monitoring traffic and activities to identify abnormal or malicious behavior.

Prevention: Taking action to stop threats once detected, such as blocking malicious traffic or stopping exploit attempts.

When split tunneling is enabled with the "Both Network Traffic and DNS" option in the GlobalProtect portal configuration, it allows the firewall to control which traffic is sent over the VPN tunnel and which is not. Specifically, it determines which domains are resolved by the VPN-assigned DNS servers (for domains requiring VPN access) and which are resolved by local DNS servers (for domains that can be accessed without the VPN tunnel).

In the Palo Alto Networks architecture, establishing a site-to-site VPN requires a clear understanding of how the Security Policy engine interacts with different traffic flows. According to technical documentation (Step 7 of the IPSec configuration guide), there are two distinct categories of traffic to consider: theControl Plane(negotiation) and theData Plane(transit).

First, the IKE negotiation (UDP 500/4500) and IPSec/ESP packets are directed at the firewall’s own external interface. Because the peer gateway is usually reachable through the same zone as that interface (e.g., 'Untrust'), the traffic is processed asintrazone. By default, PAN-OS includes anintrazone-defaultsecurity policy set to 'Allow'. Consequently, the tunnel can technically establish without an explicit rule, provided no manual 'Deny All' rule precedes it. This confirms that negotiation is allowed by default via the intrazone policy.

Second, regarding the data traffic entering or exiting the tunnel interface, the firewall applies standard zone-based inspection. While the firewall is stateful and policies are unidirectional, the documentation specifies that creating separate rules for each direction (one for inbound and one for outbound) isoptional. An administrator can choose to create two granular rules for tighter control or combine both directions into a single rule by adding both the internal and tunnel zones to the source and destination fields. This flexibility allows for a more streamlined rulebase while still meeting security requirements.

To ensure high availability (HA) across multiple availability zones (AZs) in a cloud service provider (CSP) environment, using a load balancer with health probes is a recommended method. This setup ensures that traffic can be directed to the healthy NGFW instances across multiple availability zones. If one NGFW instance or availability zone goes down, the load balancer can redirect traffic to the available instance(s) in other zones, providing redundancy and maintaining service availability.

In the context of GlobalProtect with certificate-based authentication, certificate profiles are used to ensure proper validation of the certificates. They perform the following functions:

Define trust anchors, which are the root and intermediate Certificate Authorities (CAs) that the firewall trusts to authenticate certificates.

Specify revocation checks, such as CRL (Certificate Revocation List) and OCSP (Online Certificate Status Protocol), to ensure that the certificates being used have not been revoked.

Map certificate attributes, such as the Common Name (CN), which helps in authenticating users and devices based on their certificates.

In a Palo Alto Networks SSL Forward Proxy deployment, theDecryption Profileis the primary policy component used to control how the firewall handles various technical aspects of the decryption process. While the SSL Forward Proxy itself uses a Forward Trust Certificate to resign certificates for the client, the firewall must first perform its own due diligence on the server-side certificate received from the external web server.

The Decryption Profile allows the administrator to define granular security checks for the session. Specifically, within theSSL Decryption Settingstab of the profile, there are options for "Certificate Revocation Checking." Here, the engineer can enable and define how the firewall performsOnline Certificate Status Protocol (OCSP)andCertificate Revocation List (CRL)checks. These mechanisms are used to verify that the external server's certificate has not been revoked by its issuing CA before the firewall proceeds with the decryption and re-signing process.

Failure to configure these settings within the Decryption Profile would mean the firewall might trust and proxy a connection to an external site that has a technically valid but revoked certificate, creating a significant security hole. Unlike an SSL/TLS Service Profile (which is used for trafficterminatingat the firewall) or the Forward Trust Certificate (used for theclient-sidetrust), the Decryption Profile specifically dictates thevalidation behaviorfor outgoing proxied sessions.

Local firewall rules are evaluated after Panorama pre-rules (those applied before the firewall’s local policies) and before Panorama post-rules (those applied after the firewall’s local policies). This ensures that the local firewall rules do not override the central Panorama policy and are only applied in the appropriate order within the policy evaluation sequence.

When configuring link monitoring for high availability (HA) on a Palo Alto Networks NGFW, the following interface types are supported:

Virtual Wire: Used when you have a transparent mode firewall deployment, where the firewall operates at Layer 2 to monitor traffic between two network segments.

Layer 2: Also used in transparent mode, where the firewall operates as a Layer 2 device and can be configured for link monitoring.

Layer 3: Used in routed mode, where the firewall is involved in routing traffic and can also be configured to monitor links.

In a Multi-VSYS (Virtual System) architecture, Palo Alto Networks firewalls require a specific logical construct to facilitate communication that stays within the physical device. While traditional Layer 3 zones must be bound to physical interfaces, sub-interfaces, or aggregate groups,inter-VSYS communicationrelies on a specialized zone configuration known as theExternalzone type.

When traffic is routed between virtual routers using the next-vr command, the firewall needs a logical "hand-off" point to pass the session from one VSYS context to another. To achieve this, an engineer must create a zone in each VSYS and explicitly set itsType to External. These External zones do not attach to physical ports; instead, they serve as the entry and exit points for the internal backplane.

If the engineer attempts to use a standard Layer 3 zone for this purpose without an associated physical interface, the traffic will fail to egress the source VSYS or ingress the destination VSYS. Even if theSecurity PolicyandVirtual Routersettings are technically accurate, the session cannot be established because the logical path is incomplete. Therefore, assigning theExternal zone typeis a mandatory architectural requirement to bridge the gap between two logically separated virtual systems within the same hardware chassis.

When building a custom report on a Palo Alto Networks NGFW, you can select detailed logs that provide specific insights into various aspects of firewall activity. The available options for detailed logs typically include:

Traffic logs: These provide information on the network traffic passing through the firewall.

Threat logs: These logs capture data related to identified security threats, such as malware or intrusion attempts.

Data filtering logs: These logs capture events related to data filtering policies, such as preventing the transfer of sensitive data.

User-ID logs: These logs associate user identities with the traffic and activities observed on the firewall, enabling user-based policy enforcement.

For a mission-critical network, it is recommended to configure the content update threshold to 8 hours. This ensures that the network is protected with the latest threat intelligence, updates to signatures, and other critical content, minimizing the exposure to newly discovered vulnerabilities and threats.

Regular content updates are crucial in mission-critical environments to ensure the firewall is up-to-date with the latest protections. 8 hours is considered an optimal balance between timely updates and network performance.

Palo Alto Networks Panorama provides a centralized management platform that allows administrators to manage firewalls through two primary constructs:TemplatesandDevice Groups. When working directly within the Panorama UI (without switching to the firewall's context), an administrator interacts with these constructs to push configurations down to the managed devices.

The tasks listed inOption Crepresent the core functionality of Panorama's hierarchical management:

Edit a post-rule:Security policies are managed withinDevice Groups. Post-rules are specific rules that appear after any locally defined rules on the firewall, allowing Panorama to enforce a "bottom-line" security posture across all managed devices.

Create a new certificate profile:Object management, including certificate profiles, is handled within Templates or Device Groups (depending on scope) and can be easily defined at the Panorama level.

Configure the firewall's hostname:System-level settings, such as hostnames, DNS, and NTP, are managed viaTemplates.

Conversely, the other options include tasks that generally require a direct connection or a "Context Switch" to the specific firewall's management plane. For example, viewingreal-time session details(Option A) or thelocal ACC(Option B) requires querying the specific firewall's dataplane. While Panorama can trigger a software update, performing adevice reboot(Option A) or managinglocal administrator accounts(Option D) are typically performed either locally or through the context switch to ensure the administrator is interacting with the device's specific local database rather than the global Panorama template.

Before a firewall administrator can define policy rules based on users and groups, the Group Mapping settings must be configured. These settings enable the firewall to map users to their respective Active Directory (AD) groups. This mapping allows the firewall to use user and group information to create policy rules based on group membership.

In a Palo Alto Networks Layer 2 deployment, the firewall acts as a transparent bridge between network segments. To facilitate this, the engineer must first create aVLAN objectand assign the physical Layer 2 interfaces to it. While the VLAN object handles the MAC-address learning and switching logic, the firewall’s security engine still requires that these interfaces be assigned toSecurity Zonesto enforce traffic inspection.

The reason clients cannot communicate in the described scenario is rooted in the firewall’szone-based policy architecture. Even if multiple interfaces belong to the same logical VLAN, if those interfaces are assigned to different security zones (e.g., "L2-Finance" and "L2-HR"), the firewall treats the traffic as inter-zone. By default, theinterzone-defaultsecurity policy is set toDeny. Therefore, even though the traffic is staying within the same broadcast domain (VLAN), the firewall will drop the packets unless a specific Security Policy is created to permit traffic between those zones.

Option C is the correct resolution because it acknowledges that "appropriate" zone assignment often involves segmentation for security purposes. Once segmented, explicit policies are mandatory. Options A and D are incorrect becauseIP routingis a Layer 3 function and is not used for Layer 2 interfaces, which do not have IP addresses assigned to the physical interfaces themselves.