SD-WAN-Engineer Exam Dumps - Paloalto Networks Network Security Administrator Questions and Answers

In the Prisma SD-WAN ecosystem, the centralized cloud controller provides a robust multi-layered visibility framework to ensure network reliability. To effectively detect critical events like site outages or application performance issues (SLA violations), the controller aggregates several types of operational data. Incidents are the primary mechanism for high-level alerting; they are automatically generated when the system detects significant state changes, such as an ION device going offline (site outage) or a path failing to meet the required performance metrics.

While Incidents provide the "what" and "where," Alerts offer granular notifications for specific events that may not yet have escalated to a full-scale incident. To provide deep context, the controller also utilizes Statistics, which include real-time and historical telemetry regarding bandwidth, latency, jitter, and packet loss. These statistics allow administrators to visualize the specific SLA violation as it occurs. Furthermore, Audit logs are essential for tracking configuration changes or administrative actions that might have preceded an outage, helping engineers correlate human intervention with network behavior.

By combining these four elements—Incidents for major events, Alerts for specific notifications, Statistics for performance validation, and Audit logs for change tracking—a network administrator gains a 360-degree view of the fabric. This comprehensive approach moves beyond simple "up/down" monitoring, allowing for "Day 2" operational excellence where performance degradation is identified and remediated before it impacts the end-user experience.

Comprehensive and Detailed Explanation

In a Prisma SD-WAN Data Center deployment, the operational state of the Secure Fabric VPNs (overlay tunnels) is directly tied to the health of the BGP Core Peer configuration.4

Core Peer Dependency: DC ION devices typically peer with the data center core switch (Core Router) via BGP to learn the subnets (prefixes) for the applications hosted in the DC. The Prisma SD-WAN controller monitors this BGP peering status.5

Controller Logic: If the BGP Core Peer on a DC ION goes down (or is not established), the controller automatically marks the VPN tunnels terminating at that specific ION as "Inactive".6 This is a fail-safe mechanism designed to prevent remote branches from sending traffic to a DC ION that has lost conne7ctivity to the internal data center network (and thus the applications).

Scenario Analysis: In this scenario, DC ION-1 has active VPNs, meaning its BGP Core Peer is UP and it is successfully advertising reachability. DC ION-2 has no active VPNs, which strongly indicates that its BGP Core Peer is down.8 Because the controller sees the peer is down, it suppresses the tunnel establishment or marks existing tunnels as inactive to ensure traffic is only directed to the healthy node (ION-1).

Comprehensive and Detailed Explanation

The Self-Zone is a predefined security zone in the Prisma SD-WAN ZBFW that represents the ION device's own control plane and management traffic.

Default Rule: The security policy contains an implicit, uneditable default rule that Allows traffic originating from the Self-Zone to any destination zone (Internet, Private WAN, etc.).

Rationale: This ensures that the device can always perform essential critical functions—such as connecting to the Cloud Controller, resolving DNS, syncing time via NTP, and establishing VPN tunnels—without the administrator needing to manually create "Allow" rules for the device itself. If this traffic were blocked by a "Deny All" default, the device would become unmanageable (bricked) immediately after applying the policy.

Comprehensive and Detailed Explanation

Dynamic VPNs (also known as ION-to-ION or Branch-to-Branch VPNs) allow Prisma SD-WAN devices to establish direct, on-demand secure tunnels between branch sites to optimize latency for peer-to-peer traffic (e.g., VoIP calls between offices).

To enable this capability, the primary architectural requirement is the configuration of VPN Clusters.

A VPN Cluster defines a logical group of devices that are authorized to communicate with one another.

By default, or if devices are in different clusters without peering, the topology typically defaults to Hub-and-Spoke, where branches only talk to the Data Center.

When two branch ION devices are placed into the same VPN Cluster (or peered clusters), the controller shares the necessary reachability and cryptographic information between them.

Once in the same cluster, the ION devices monitor traffic. If a user at Branch A tries to contact a server at Branch B, the ION devices detect this interest. If a direct path is available (e.g., via public internet), they will dynamically negotiate a direct VPN tunnel, bypassing the Data Center hub. This offloads the hub and reduces latency. Option B is incorrect because SD-WAN eliminates manual GRE config. Option C is incorrect because dynamic VPNs are a performance feature, not just a disaster recovery feature.

Comprehensive and Detailed Explanation

The Prisma SD-WAN (ION) QoS engine utilizes a hierarchical queuing structure designed to provide granular control over application performance. Each WAN interface on an ION device supports a total of 16 QoS queues.

This 16-queue structure is derived from a matrix of 4 Classes (often referred to as Priority Classes) multiplied by 4 Application Criteria (Traffic Types).2

4 Priority Classes: The system defines four high-level business priority categories:3

Platinum (Highest priority)4

Gold

Silver

Bronze (Lowest priority/Best Effort)5

4 Application Criteria (Sub-queues): Within each of the four priority classes, the system further categorizes traffic into four specific application types to ensure proper handling (e.g., ensuring voice doesn't get stuck behind bulk data even within the same priority level):6

Real-Time Video

Real-Time Audio

Transactional

Bulk7

Calculation: 4 Priority Classes × 4 Application Types = 16 Total Queues per interface. This structure allows the scheduler to ensure that a "Platinum" voice call is prioritized over "Platinum" bulk data, and both are prioritized over "Gold" traffic.

Comprehensive and Detailed Explanation

The CLI command debug controller reachability (e.g., debug controller reachability 1) is the specific diagnostic tool designed to verify the entire connectivity chain required for management plane availability.

Unlike a simple ICMP ping (Option A), which only tests Layer 3 connectivity to an IP address, the debug controller reachability command performs a sequential set of tests:

DNS Resolution: It attempts to resolve the specific Locator service URL (locator.cgnx.net or region-specific FQDN) to verify DNS functionality.

TCP Connectivity: It tests the ability to establish a TCP connection to the controller on port 443 (HTTPS).

SSL/TLS Handshake: It validates that the device can successfully negotiate the secure tunnel required for authentication.

If this command fails at the DNS step, the issue is likely a missing DNS server in the interface config. If it fails at the TCP step, it implies an upstream firewall is blocking outbound port 443. This targeted output allows the engineer to pinpoint exactly why the device is offline in the portal.

Comprehensive and Detailed Explanation

The RMA replacement process in Prisma SD-WAN is designed to be seamless, leveraging the decoupling of logical configuration from physical hardware.

Replace Device Workflow: The administrator should use the "Replace Device" (or RMA) function within the portal. This workflow allows you to select the "Defective" device (old serial) and the "Replacement" device (new serial).

Configuration Transfer: Once executed, the system automatically binds the existing Device Shell (which contains all interface configs, routing policies, and site associations) to the new hardware's serial number. The new device, once connected to the internet, will "call home," identify itself, and download the exact configuration of the previous unit.

License Transfer: While the configuration moves automatically, the Support License transfer typically requires a specific step in the Customer Support Portal (CSP) or happens automatically if processed as a formal RMA order. Options A and D are incorrect because they involve manual reconfiguration, which is unnecessary and error-prone. Option C is incorrect as the ION platform relies on cloud-based config management, not local USB backups for hardware swaps.

Comprehensive and Detailed Explanation

Prisma SD-WAN utilizes Link Quality Monitoring (LQM) to maintain a real-time health score for every WAN path.

To ensure the system knows the quality of a path before sending critical user traffic onto it, the ION device uses Active Probing.

Mechanism: The ION sends synthetic probe packets (typically UDP) across the Secure Fabric (VPN tunnels) and Direct Internet paths to its peers. These probes measure Latency, Jitter, and Packet Loss.

Active vs. Passive: While the system does use Passive Monitoring (observing actual user flows) when traffic is present to reduce overhead, Active Probes are essential for idle links or backup paths. Without active probing, the ION would have no data to make an intelligent steering decision for the first packet of a new video call. This ensures that "Real-Time" policies always have up-to-date metrics to select the best path immediately.

Comprehensive and Detailed Explanation

In the Prisma SD-WAN Data Center (DC) model, the terminology for BGP peers defines their role in the topology and how the system generates route maps.

Core Peer: This peer type is designated for the LAN-side connection (facing the DC Core Switch or internal Routers). Its primary purpose is to learn the subnets/prefixes hosted in the data center so the ION can advertise them to the remote branches. The system automatically creates route maps to facilitate this redistribution into the fabric.

Edge Peer: This peer type is designated for the WAN-side connection (facing the Edge Router or MPLS PE). Its primary purpose is to provide reachability to the underlay network.

Distinction: Selecting the correct type affects the default Route Maps and Prefix Lists generated by the controller. Configuring a Core Peer correctly ensures that the DC's internal subnets are properly learned and propagated to the overlay, whereas an Edge Peer configuration focuses on WAN next-hop reachability.

In a Prisma SD-WAN deployment, the routing of traffic between branches and Data Centers (DCs) relies on the proper synchronization between the AppFabric (the overlay) and the local routing protocols (the underlay/LAN side). In this scenario, the branch can successfully reach DC1, indicating the branch ION is correctly participating in the fabric. However, traffic to DC2 (10.2.2.22) is failing.

The DC2 site has the site prefix 10.2.2.0/23 configured. In Prisma SD-WAN, defining a site prefix informs the Controller that this specific subnet "belongs" to that site, causing the Controller to advertise reachability for this prefix to all other ION devices in the fabric. Consequently, when the branch ION (192.168.1.123) attempts to reach 10.2.2.22, it correctly identifies DC2 as the destination and encapsulates the traffic toward the DC2 ION.

The bottleneck occurs once the packet arrives at the DC2 ION. While the ION is advertising the branch subnet (192.168.1.0/24) to the DC Core (ensuring the return path), the ION itself must know how to forward the incoming traffic from the branch to the internal DC network. If the DC2 ION does not have a specific route in its local routing table for the 10.2.2.0/23 subnet pointing to the DC Core's internal interface, the packet will be dropped.

According to Palo Alto Networks best practices for Data Center ION deployment, a static default route (0.0.0.0/0) should be configured on the ION device pointing toward the DC Core’s next-hop IP address. This ensures that any traffic received from the AppFabric destined for internal DC resources—which are not directly connected to the ION—is successfully handed off to the core switching fabric for final delivery. Adding this default route (Option A) resolves the reachability issue by providing the "last-hop" routing instruction within the DC.