Pass the Paloalto Networks Network Security Administrator NGFW-Engineer Questions and answers with CertsForce

To successfully implement an IPSec VPN on a Palo Alto Networks NGFW, the security architect must account for two distinct types of traffic:Control Plane(tunnel negotiation) andData Plane(traffic through the tunnel).

First, for the tunnel to establish, the firewall must permit negotiation traffic. While IKE (UDP 500/4500) is the protocol used, Palo Alto Networks uses theIPSec container applicationto represent the underlying encrypted tunnel traffic. This traffic is typically destined for the firewall's own "Local" zone (the management/loopback or physical interface IP). Therefore, a policy must exist to allow theipsec-esp-udpor the broaderIPSecapplication between the external-facing zone and theLocal zone.

Second, once the tunnel is active, the decrypted traffic emerges from theTunnel Interface. This interface must be assigned to a security zone (often a dedicated "VPN" zone or an existing internal zone). Because the NGFW is a stateful, zone-based firewall, theinterzone-defaultpolicy is "Deny" by default. Consequently, a pair of security policies is required to allow data to flow: one for traffic entering the tunnel (e.g., Trust to VPN) and one for traffic exiting the tunnel (e.g., VPN to Trust). Without these specific rules, the tunnel may show as "Up" (Phase 1 and 2 complete), but no production data will pass through it.

When implementing a new self-signed root certificate authority (CA) for SSL decryption on a Palo Alto Networks firewall, the subordinate CA certificate (which is generated by the firewall) must be imported into the trust stores of all client devices. This ensures that client devices trust the firewall as a valid certificate authority, enabling the firewall to decrypt and re-encrypt SSL traffic.

Importing the subordinate CA certificate into the client devices' trust stores is necessary for those devices to trust the new self-signed root CA and properly handle SSL decryption traffic.

The Proxy IDs (or Traffic Selectors) define the local and remote subnets that are allowed to communicate over the IPSec tunnel. If the Proxy IDs on the Palo Alto Networks firewall do not match the configuration on the Cisco ASA, the tunnel will fail to establish because the firewalls won't agree on which traffic to encrypt. Ensuring that the Proxy IDs match between the Palo Alto Networks firewall and the Cisco ASA will resolve the issue.

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.

In the context of a Zone Protection profile, Protocol Protection is the section used to configure protections against activities such as spoofed IP addresses and split handshake session establishment attempts. These types of attacks typically involve manipulating protocol behaviors, such as IP address spoofing or session hijacking, and are mitigated by the Protocol Protection settings.

The Transient zone type is used to allow traffic between zones in different virtual systems (VSYS) on a Palo Alto Networks firewall without the traffic leaving the firewall. It provides a way for virtual systems to communicate with each other by acting as a temporary or intermediary zone. Traffic can pass through the firewall between the virtual systems without requiring physical interfaces or leaving the device.

When configuring a Multi-VSYS environment on a Palo Alto Networks firewall, the administrator can manage and restrict the consumption of hardware resources by individual virtual systems usingResource Quotas. This is a critical architectural step to prevent a single VSYS (tenant) from exhausting the firewall's capacity, which could impact other virtual systems on the same physical chassis.

On theResource tabwithin the Virtual System configuration (found underDevice > Virtual Systems), administrators can set specific limits for various policy types and session counts. Valid configurable limits include:

Sessions Limit(to control the total number of concurrent sessions per dataplane).

Security Rules, NAT Rules, andDecryption Rules.

DoS Protection, QoS, and Application Override rules.

VPN Tunnel limits (Site-to-Site and Concurrent SSL VPN tunnels).

Option B is correct becauseDecryption Rulesare specifically listed as a configurable quota. It is important to note that the firewall does not support limitingCPU utilization(Option A) orMemoryon a per-VSYS basis; these resources are dynamically shared based on traffic demand. While you can assign aVirtual Router(Option C) to a VSYS, it is not treated as a "quota" that you limit by quantity in the resource settings. Similarly,Disk space allocation(Option D) is typically managed at the log database level for the entire device or directed to external collectors, rather than being partitioned as a VSYS resource quota.

In a multi-vsys (Virtual System) architecture on a Palo Alto Networks firewall, communication between two virtual systems can occur internally through the firewall's backplane without requiring the traffic to exit through a physical interface to an external switch or router. To facilitate this internal routing, a specialized zone type is required.

While Layer 3 zones are used for standard routed traffic and are bound to physical or logical interfaces, theExternalzone type is specifically designed for inter-vsys communication. When an engineer configures two virtual systems to talk to one another, they must create a zone in each VSYS and set the Type toExternal. These zones act as the logical "entry" and "exit" points for traffic crossing the VSYS boundary.

For the traffic flow to be successful, the Virtual Router in the source VSYS must have a route (typically a next-vr route) pointing to the Virtual Router in the destination VSYS. However, from a security policy perspective, the firewall sees the traffic as egressing the External zone of the source VSYS and ingressing the External zone of the destination VSYS. Without defining these zones asExternal, the firewall cannot logically associate the session with the internal backplane hand-off, and the traffic will be dropped despite having correct routing entries. This architectural requirement ensures that even internal virtual traffic remains subject to the firewall's zone-based security inspection.