PCNSA Practice Test 38 — 15 Questions

Question 1

A company has deployed a pair of PA-5250 firewalls in an Active/Passive HA configuration. The management network uses a separate subnet with addresses 10.0.0.0/24. The active firewall's management IP is 10.0.0.1, passive is 10.0.0.2. They have a virtual router configured with static routes. The HA configuration uses HA1 (backplane) for heartbeat and HA2 for session sync. After a power failure, both firewalls reboot. The active firewall comes up first and becomes active. The passive firewall later joins, but fails to become passive; it remains in 'non-functional' state. The administrator observes the following:
- HA1 link is up on both firewalls.
- HA2 link shows 'waiting for HA2 link' on the active.
- The passive firewall's management IP is reachable.
- The active firewall shows 'peer unreachable' in HA status.
What is the most likely cause?

Accepted Answer

The HA2 cable is faulty or misconfigured. The active firewall shows 'waiting for HA2 link' and 'peer unreachable' despite HA1 being up and the passive management IP being reachable. This indicates that the HA2 link, which is responsible for session synchronization and state propagation, is not functioning. Since HA2 is required for the passive firewall to transition to a passive state, a faulty or misconfigured HA2 cable prevents the passive firewall from becoming operational, leaving it in a 'non-functional' state.

Answer

The management interface on the passive is misconfigured

Answer

The HA1 configuration is missing the peer's management IP

Answer

The passive firewall has a different PAN-OS version

Question 2

An administrator is tasked with centralizing the management of 50 Palo Alto firewalls spread across four geographical regions. The company has a Panorama VM deployed in the data center. Each firewall must receive a common set of security policies and URL filtering profiles, but regional administrators need the ability to add locally required policies. The administrator configures Panorama with device groups: 'Shared' device group for global policies, and four regional device groups (Americas, EMEA, APAC, Oceania). They create a template for basic network settings and use template stacks. After pushing the Device Group and Template configuration, some regional firewalls report that they are not receiving the shared policies. What is the most likely cause?

Accepted Answer

The 'Shared' device group is not included in the device group hierarchy for the regional device groups. The 'Shared' device group is automatically included in the device group hierarchy for all firewalls managed by Panorama, but only if the regional device groups are configured as children of the 'Shared' group. If the regional device groups are created as top-level groups instead of being nested under 'Shared', the firewalls assigned to those regional groups will not inherit the shared policies. This is the most likely cause because the shared policies are not being pushed to the firewalls due to a missing hierarchy relationship.

Answer

The firewalls are not connected to Panorama due to management IP misconfiguration

Answer

Regional administrators created local policies in their own device groups with higher order than shared policies

Answer

The template stack does not include the shared template

Question 3

A healthcare organization uses Palo Alto Networks firewalls to secure patient data. They have strict compliance requirements to log all access to medical records servers. The servers are grouped in an address group "Medical-Servers". The administrator wants to ensure that any security policy that uses this address group as destination also logs the session end. They also want to reduce administrative overhead. What is the best way to enforce logging for all policies referencing this group?

Accepted Answer

Use the address group in a security policy and enable logging at session end in that policy.. Option D is correct because it allows the administrator to enable logging at session end directly on a single security policy that uses the address group 'Medical-Servers' as the destination. This ensures all traffic matching that policy is logged without needing to modify multiple policies, reducing administrative overhead while meeting compliance requirements.

Answer

Create a security policy with a log setting at the end of the rulebase that matches traffic to the group.

Answer

Configure a log forwarding profile and apply it to each policy using the group.

Answer

Use a policy optimizer to automatically add logging to policies.

Question 4

A company runs a pair of PA-5250 firewalls in active/passive HA controlling the production data center (10 Gbps traffic). The security team needs to upgrade from PAN-OS 10.0 to 10.2 to fix several critical CVEs. The team has a maintenance window of four hours. The lead engineer suggests performing the upgrade in the following order: 1. Download and install the upgrade on the passive firewall, 2. Commit after install, 3. Perform a non-disruptive failover to make the passive active, 4. Upgrade the new passive (former active), 5. Fail back to the original active. A junior engineer points out that the passive firewall takes 30 minutes to boot and join the HA pair after upgrade. The maintenance window is only four hours. What should the team do to ensure the upgrade completes within the window?

Accepted Answer

Pre-stage the software download on both firewalls before the maintenance window begins.. Option C is correct because pre-staging the software download on both firewalls before the maintenance window eliminates the time required for the download step, which can be significant over a WAN or slow management connection. This allows the team to focus the four-hour window solely on the installation, reboot, and HA synchronization steps, which are the time-critical components. Since the passive firewall takes 30 minutes to boot and join the HA pair, pre-staging ensures the download (which could take 30–60 minutes or more) does not consume valuable window time.

Answer

Upgrade both firewalls simultaneously during the window to save time.

Answer

Use the 'request high-availability sync-to-remote' command to speed up the upgrade.

Answer

Perform the upgrade as planned, but skip the final fail-back to save 15 minutes.

Question 5

A company uses a Palo Alto Networks firewall to control outbound access. They have created custom application filters to block social media and streaming. However, they need to allow a specific corporate YouTube channel for training videos. The administrator creates an application group "Corporate-YouTube" containing the "youtube-base" application, and adds a security rule to allow traffic from internal users to the application group. Despite this, users still cannot access the corporate YouTube channel. What is the most likely reason?

Accepted Answer

The firewall's URL filtering profile is blocking the category before application identification can occur.. The most likely reason is that the URL filtering profile is blocking the YouTube category before the firewall can identify the application. Palo Alto Networks firewalls process URL filtering before application identification in the security policy evaluation order. Even though the application group 'Corporate-YouTube' is allowed, the URL filtering profile (which is applied to the rule or as a default) will block the request if the URL category (e.g., 'streaming-media' or 'social-networking') is denied, preventing the traffic from reaching the application identification stage.

Answer

The application group is not correctly associated with the security policy.

Answer

The application "youtube-base" is not recognized by the firewall.

Answer

The security rule allowing the application group is placed after a deny rule that blocks the "streaming" category.

Question 6

A medium-sized enterprise recently deployed a pair of PA-5250 firewalls in an active/passive high-availability configuration. The network team notices that after a failover event, the new active firewall does not pass any traffic for about 30 seconds, even though the session table is synchronized. Users report that existing connections break and need to be re-established. The firewall is configured to use session state synchronization and failover triggers based on link state and ping to the next-hop gateway. Which action should the administrator take to minimize traffic disruption during failover?

Accepted Answer

Configure asymmetric path bypass on the high-availability settings.. Option A is correct because asymmetric path bypass allows the new active firewall to accept and forward packets for existing sessions even before the session table is fully synchronized or the routing converges. In an active/passive HA pair, after failover, the new active firewall may receive packets for flows that were originally processed by the previous active unit; without asymmetric path bypass, these packets are dropped because the firewall does not recognize them as part of an existing session. Enabling this feature ensures that the firewall temporarily bypasses session lookup for such packets, reducing the 30-second traffic blackout.

Answer

Increase the packet buffer size on the firewall to handle burst traffic.

Answer

Reduce the hold timer for path monitoring to the next-hop gateway.

Answer

Enable preemptive mode for the active/passive HA pair.

Question 7

A large financial institution runs a PA-5250 firewall in a virtual wire mode between two core switches. The firewall is configured with multiple virtual wire sub-interfaces to segregate traffic for different VLANs. Recently, the security team noticed that multicast traffic from a critical trading application is not being forwarded across the virtual wire link. The firewall has multicast policies enabled, and the trading application uses IGMPv3. The administrator has verified that the firewall's multicast policy allows the traffic and that the IGMP snooping is enabled on the adjacent switches. However, the multicast stream does not reach the receivers on the other side. Which step should the administrator take to resolve this issue?

Accepted Answer

Enable IGMP snooping on the virtual wire sub-interfaces of the firewall.. In a virtual wire deployment, the firewall does not participate in Layer 2 protocols like IGMP snooping by default. Even if multicast policies are enabled, the firewall must explicitly perform IGMP snooping on its virtual wire sub-interfaces to track multicast group memberships and forward the traffic correctly. Enabling IGMP snooping on the sub-interfaces allows the firewall to intercept IGMPv3 membership reports and build the necessary forwarding state for the multicast stream.

Answer

Increase the multicast traffic bandwidth limit in the QoS policy.

Answer

Change the virtual wire mode to layer 3 mode and configure PIM.

Answer

Configure a static multicast MAC address mapping on the firewall.

Question 8

A small business uses a single PA-220 firewall for internet access and has three internal zones: Trust, DMZ, and Guest. Users in the Trust zone report intermittent connectivity to a public cloud application. The firewall administrator checks the traffic logs and sees that sessions to the cloud application show "Application: ssl" and "Action: allow". The administrator suspects the issue might be related to decryption. The firewall currently has a decryption policy that decrypts all outbound HTTPS traffic for threat inspection. The cloud application uses certificate pinning and breaks when decrypted. What is the best solution to allow this application to function while still decrypting other traffic?

Accepted Answer

Create a decryption exclusion rule for the specific cloud application by source or URL category.. Option B is correct because creating a decryption exclusion rule for the specific cloud application (by source IP, URL category, or destination) allows the firewall to bypass decryption for that traffic while continuing to decrypt all other outbound HTTPS traffic. This resolves the certificate pinning issue without compromising security for other traffic. Decryption exclusion rules are a standard feature in PAN-OS for handling applications that break under decryption.

Answer

Upgrade the firewall to a model that supports certificate key protection.

Answer

Disable SSL decryption entirely.

Answer

Change the decryption policy to decrypt only inbound traffic.

Question 9

A company has two Palo Alto Networks firewalls in an active/passive HA pair (PA-5250) running PAN-OS 10.1. The HA configuration uses dedicated HA1 (control link) and HA2 (data link) interfaces. The network team recently replaced a failed switch that connected the HA1 interfaces. After the switch replacement, the HA pair is not forming. The administrator logs into the active firewall and runs 'show high-availability state' which shows the local state as 'active' and the peer state as 'unknown'. The HA1 interface status shows 'link down'. The administrator checks the physical connections and confirms the cables are connected and the switch ports are up. What is the most likely cause and the best course of action?

Accepted Answer

Verify that the HA1 interfaces are on the same VLAN and can ping each other using the configured HA1 IP addresses. The correct answer is D because the HA1 interfaces must be on the same Layer 2 domain (VLAN) and able to communicate via ICMP to form the control link. The 'link down' status on the HA1 interface, despite physical connectivity, indicates a Layer 2 misconfiguration (e.g., VLAN mismatch or port mode issue) on the replaced switch. Verifying that the HA1 IP addresses can ping each other confirms Layer 3 reachability, which is essential for HA1 heartbeats and state synchronization.

Answer

Ensure that the HA2 interfaces are also connected and configured correctly

Answer

Change the HA2 IP addresses to be on the same subnet as HA1

Answer

Enable HA ping on the HA1 interface to test connectivity

Question 10

A medium-sized enterprise has deployed a Palo Alto Networks firewall in a branch office. They use App-ID to control access to cloud applications. Recently, they migrated from on-premises Exchange to Office 365. They have a security rule that allows 'office365-base' for all users. However, users report that they cannot access their Office 365 email via Outlook client, although web access works fine. The firewall logs show that the traffic is being allowed as 'office365-base' but no other Office 365 sub-applications are seen. The IT team suspects that App-ID is not fully identifying the Outlook client traffic. What should they do to resolve this issue?

Accepted Answer

Modify the existing rule to allow 'office365-base' and other Office 365 sub-applications like 'office365-outlook' and 'office365-exchange'.. Option B is correct because the 'office365-base' App-ID only provides basic identification for Office 365 traffic, but Outlook client traffic requires more specific sub-applications like 'office365-outlook' and 'office365-exchange' to be explicitly allowed in the security rule. Without these sub-applications, the firewall may allow the traffic as 'office365-base' but fail to fully identify and permit the Outlook client's proprietary protocols, such as MAPI over HTTP or RPC over HTTPS, which are necessary for email functionality.

Answer

Enable SSL decryption to allow App-ID to identify the Outlook traffic.

Answer

Create a new rule that allows 'outlook' application specifically.

Answer

Change the rule to allow 'office365-base' and set Action to 'allow' with a QoS policy.

Question 11

A mid-sized enterprise has deployed a Palo Alto Networks firewall with SSL Forward Proxy decryption for outbound traffic. The firewall uses a CA-signed certificate from a public CA, and the certificate is installed on all corporate-managed endpoints. Recently, the security team noticed that a few users are unable to access a specific external SaaS application (app.example.com) over HTTPS. Other users can access it without issues. The firewall logs show that for these users, the session is being decrypted and no threat is detected. The application uses a valid certificate from a public CA. The affected users are in the same IP subnet and use the same browser version. Which is the most likely cause?

Accepted Answer

The firewall's CA certificate is not installed or trusted on the affected users' endpoints.. Option C is correct because SSL Forward Proxy decryption requires the firewall to generate a new certificate on-the-fly for the destination server, signed by the firewall's own CA certificate. If the CA certificate is not trusted on the affected users' endpoints, the browser will display a certificate warning or block the connection entirely, even though the decryption policy is applied and no threats are detected. Since other users in the same subnet can access the application, the issue is isolated to the trust store on the affected machines, not the network or decryption policy.

Answer

The decryption policy is set to 'No Decrypt' for the affected users' source IP range.

Answer

The firewall is performing SSH proxy instead of SSL decryption for those users.

Answer

The SaaS application's certificate has expired for those users due to time zone differences.

Question 12

A security administrator manages a Palo Alto Networks firewall in a large enterprise. The company has multiple remote sites connected via IPSec VPNs. Each site has its own subnet (e.g., Site A: 10.10.1.0/24, Site B: 10.10.2.0/24). The administrator needs to create a security policy that allows all inter-site traffic but blocks all traffic to and from the internet except for specific services. The administrator wants to use address groups to simplify management. Currently, there are address groups for each site (e.g., 'Site-A-Networks', 'Site-B-Networks') containing the respective subnets. The administrator also has an address group 'Internet-Allow' for allowed external IPs. The policy should have a rule that permits traffic from any site to any other site, and a rule that permits traffic from internal networks to the 'Internet-Allow' group for destination ports 80 and 443. Which of the following approaches best achieves this with minimal administrative overhead?

Accepted Answer

Create a dynamic address group with filter "'Site-*-Networks'" to automatically include all site groups that follow the naming convention. Use this group in the rule.. Option D is correct because dynamic address groups with tag-based or name-based filters automatically include all matching objects, eliminating manual updates when new sites are added. By using a filter like 'Site-*-Networks', the group dynamically incorporates any address group whose name matches the pattern, reducing administrative overhead. This approach aligns with the PCNSA objective of using dynamic objects to simplify policy management in a scalable environment.

Answer

Create a static address group called 'All-Site-Networks' and manually add each site's address group as a member. Then use this group in the inter-site rule.

Answer

Create a security rule using the 'any' zone for source and destination, and rely on the existing site groups in the rule's source/destination fields.

Answer

Assign a tag 'Site-Network' to each site address object, then create a dynamic address group with filter "'Site-Network'". Use this group in the rule.

Question 13

A university uses a Palo Alto Networks firewall to protect its network. They have implemented SSL Forward Proxy decryption for all student traffic. Recently, the IT helpdesk has received complaints from students that some websites (e.g., online banking, healthcare portals) are not loading properly. The firewall logs show that these sites are being decrypted, and no threats are detected. The university's legal team has advised that decryption of financial and healthcare sites may violate regulations. The network team wants to quickly resolve the issue while ensuring compliance. What is the best course of action?

Accepted Answer

Create a decryption policy rule with action 'No Decrypt' for URL categories 'Financial Services' and 'Health and Medicine', placed above the existing decrypt rule.. Option D is correct because it creates a decryption policy rule with action 'No Decrypt' for the specific URL categories 'Financial Services' and 'Health and Medicine', placed above the existing decrypt rule. This ensures that traffic to these sensitive categories is excluded from SSL Forward Proxy decryption, resolving the loading issues caused by certificate pinning or regulatory violations, while still decrypting all other student traffic. The rule order is critical because Palo Alto Networks decryption policies are evaluated top-down, and the first match determines the action.

Answer

Modify the existing decrypt rule to decrypt all categories except those two.

Answer

Disable decryption entirely for all student traffic.

Answer

Create a security policy rule to allow traffic to those URL categories without inspection.

Question 14

A company has a Palo Alto Networks firewall in production. They recently configured a new security policy rule to allow outbound HTTPS traffic from the internal network (10.0.0.0/8) to the internet. The rule is placed after a block rule that denies all traffic from 10.0.0.0/8 to any external destination. After committing, users report that HTTPS access is still blocked. The administrator checks the firewall logs and sees that the traffic is being denied by the block rule. The administrator verifies the rule order: the new allow rule is at position 5, and the block rule is at position 3. The administrator also checks that the source zone (Trust) and destination zone (Untrust) are correct. What is the most likely cause of the issue?

Accepted Answer

The allow rule is placed below the block rule, so the block rule is evaluated first.. The Palo Alto Networks firewall evaluates security policy rules in sequential order from top to bottom. Since the block rule at position 3 is evaluated before the allow rule at position 5, traffic matching the block rule is denied immediately, and the allow rule is never reached. This is the most likely cause of the issue, as the rule order directly determines which rule is applied first.

Answer

There is a NAT policy that is interfering with the allow rule.

Answer

The allow rule has an incorrect application (e.g., ssl instead of web-browsing).

Answer

The allow rule has the wrong source address (e.g., 10.0.0.0/8 is correct).

Question 15

Your organization has deployed a Palo Alto Networks PA-5250 firewall in a high-availability active/passive configuration. The firewall is connected to two ISPs for redundancy. The internal network uses OSPF with the firewall as an ASBR redistributing a default route. Recently, users reported intermittent connectivity to external resources. During troubleshooting, you notice that the active firewall's management interface has high CPU usage, and the show session all command displays many sessions in the 'active' state but with minimal data transfer. The passive firewall shows no such issues. The OSPF neighbor relationships are stable. What is the most likely cause of the intermittent connectivity?

Accepted Answer

Asymmetric routing is occurring due to a misconfiguration in the active/passive HA setup.. In an active/passive HA configuration, only the active firewall processes traffic. If asymmetric routing occurs—where traffic from the internal network to the internet uses one ISP link on the active firewall, but return traffic arrives via the other ISP link—the active firewall may see the return traffic as a new session or a non-symmetric flow. This causes the firewall to create sessions that remain in 'active' state with minimal data transfer, as the firewall attempts to match return packets to existing sessions but fails due to path asymmetry. The high CPU on the management interface results from the control plane processing these mismatched sessions, while the passive firewall is unaffected because it does not handle traffic.

Answer

OSPF is flapping and causing route instability.

Answer

A DDoS attack is overwhelming the management plane.

Answer

The firewall's licenses have expired, causing feature degradation.