Paloalto Networks SD-WAN-Engineer Practice Test Questions Answers

Comprehensive and Detailed Explanation

The stability of VPN tunnels in the Prisma SD-WAN + Prisma Access integration relies on standard IPSec mechanisms.

Dead Peer Detection (DPD): The CloudBlade configuration automatically enables DPD on the IPSec tunnels it provisions.

Mechanism: DPD is a standard keepalive mechanism where the ION device sends periodic "R-U-THERE" messages to the Prisma Access gateway (and vice versa). If no acknowledgment is received after a specific count/timer, the ION marks the tunnel as down and attempts to re-key or switch to a backup path.

Synthetic Probes (B): While Synthetic Probes (part of ADEM or Path Quality monitoring) can be configured to measure latency/loss, the fundamental mechanism that keeps the IPSec security association (SA) active and detects link failure is DPD, not an application-layer probe.

Comprehensive and Detailed Explanation

The CloudBlade platform is a distinguishing architectural component of the Prisma SD-WAN solution. It is not a physical piece of hardware, nor is it software that runs directly on the branch ION device's CPU.

Instead, the CloudBlade platform is a cloud-based API integration layer hosted by Palo Alto Networks. It functions as an intelligent broker or "translator" between the Prisma SD-WAN Controller and external third-party services (such as Prisma Access, Amazon Web Services, Azure, ServiceNow, or Zscaler).

When an administrator configures the Prisma Access CloudBlade, for example, they input their API credentials and intent (e.g., "Connect all US branches to US West"). The CloudBlade engine then:

Communicates with the Prisma Access API to provision the remote IPSec termination nodes (Security Processing Nodes).

Translates this configuration into specific instruction sets for the Prisma SD-WAN Controller.

The Controller then pushes the necessary VPN tunnel configurations, IKE parameters, and routing rules to the relevant ION devices.

This architecture eliminates the need for manual IPSec configuration on every branch device. It ensures that if the third-party service changes its IP addresses or settings, the CloudBlade can detect the change via API and automatically update the branch fleet, maintaining connectivity without manual administrator intervention.

Comprehensive and Detailed Explanation

The transition from "Claimed" to "Online" depends entirely on the ION device's ability to establish a secure, persistent management tunnel to the Prisma SD-WAN Controller.

Connectivity Requirements: The ION device initiates an outbound connection to the controller on TCP Port 443 (HTTPS). It also requires accurate time synchronization to validate SSL certificates, necessitating access to NTP (UDP Port 123).

Scenario Analysis: Since the installer can browse the internet from the LAN, we know the physical link and basic routing/NAT are functional. The issue is specific to the management plane traffic.

Root Cause: If an upstream firewall (e.g., a corporate edge firewall or ISP filter) is inspecting SSL traffic or blocking specific FQDNs/Ports required by the ION, the device cannot complete the handshake. Consequently, it remains "Claimed" (registered in the database) but cannot go "Online" (active management session). Options A, C, and D prevent provisioning (configuration push) but generally do not prevent the device from initially checking in and going "Online" if the pipe is open.

Comprehensive and Detailed Explanation

The best practice for managing upgrades in a large-scale Prisma SD-WAN environment is the Canary or Phased Rollout approach, utilizing Site Tags.

Risk Mitigation: Upgrading all sites simultaneously (Option B) is highly risky. If the new software version has an unforeseen bug or compatibility issue with a specific circuit type, the entire network could face an outage.

Tag-Based Management: Administrators should create tags such as "Upgrade-Phase-1" (Pilot sites) or "Region-North". By assigning the specific Software Version to the Tag (rather than the individual site or the global default), the controller pushes the update only to that subset of devices.

Procedure:

Apply update to "Pilot" tag (5 sites). Monitor for 24-48 hours.

Apply update to "Region-1" tag (50 sites). Monitor.

Eventually, update the Global default once confidence is high.

Option A is unscalable, and Option D is incorrect as the administrator retains full control over when upgrades occur; they are not forced automatically without policy configuration.

Comprehensive and Detailed Explanation

To achieve strict regional isolation where branch sites only form VPN tunnels with Data Centers in their specific region (e.g., EU branches to EU DCs only), the correct architectural feature to utilize is VPN Clusters.

In Prisma SD-WAN (CloudGenix), a Cluster defines a logical security and topology boundary for the overlay network. By default, devices may be placed in a "Default" cluster where they attempt to form a mesh or hub-and-spoke topology with all other reachable devices in that context.

To enforce the new policy:

Logical Partitioning: The administrator should create separate VPN Clusters for each region (e.g., "Cluster-NA", "Cluster-EU", "Cluster-Asia").

Assignment: The Regional Data Center IONs and their corresponding Branch IONs must be moved into their respective clusters.

Result: The Prisma SD-WAN controller dictates that devices can only establish Secure Fabric (VPN) tunnels with other devices within the same cluster. This effectively segments the global network, ensuring that an Asian branch never attempts to build a tunnel to a North American DC, satisfying the compliance requirement without complex access lists or manual tunnel configuration.

Option B (Manual Tunnels) is administratively unscalable and negates the benefits of SD-WAN automation.

Option C (Circuit Labels) is primarily for path selection and traffic steering, not for hard topology segmentation.

Option D (VRFs) is used for local Layer 3 segmentation (routing isolation) within a device, not for controlling WAN overlay tunnel formation scope.