PCNSA Practice Exam 4 — 20 Questions

Question 1

After a security policy change, users complain that they cannot upload files to a custom web application. The rule allows the custom application 'webapp' and Content-ID is enabled. What is the most likely cause?

Accepted Answer

A file blocking profile is blocking the upload.. The correct answer is C because a file blocking profile, when enabled with Content-ID, can block uploads of specific file types even if the application itself is allowed. In this scenario, the rule permits the custom application 'webapp' and Content-ID is enabled, so the most likely reason for upload failure is that a file blocking profile is configured to block the file type being uploaded, not an issue with App-ID or SSL decryption.

Answer

The application 'webapp' is not allowed due to an application override.

Answer

SSL decryption is not enabled.

Answer

App-ID is not identifying the application correctly.

Question 2

Which TWO of the following are true about App-ID? (Choose two.)

Accepted Answer

App-ID identifies applications regardless of port.. App-ID is designed to identify applications based on their unique traffic behavior, not just port numbers. By using signatures, protocol decoding, and behavioral analysis, App-ID can accurately detect applications even when they are running on non-standard ports, such as SSH on TCP 2222 or HTTP on TCP 8080. This decoupling from port-based identification is a core strength of the Palo Alto Networks next-generation firewall.

Answer

App-ID cannot identify custom applications.

Answer

App-ID can only identify applications on standard ports.

Question 3

A security engineer is troubleshooting why YouTube video streaming is not being identified as 'youtube-streaming' but instead as 'youtube-base'. What could be the reason?

Accepted Answer

The traffic lacks enough signatures to identify the sub-application.. Option C is correct because App-ID uses a multi-layered approach to identify applications, including signatures, SSL decryption, and behavioral analysis. When YouTube traffic is classified as 'youtube-base' instead of the more specific 'youtube-streaming', it indicates that the firewall has identified the base application (YouTube) but lacks sufficient signatures or heuristics to differentiate the streaming sub-application. This typically occurs when the traffic does not contain enough distinct patterns (e.g., specific HTTP headers, TLS SNI, or packet sizes) to trigger the sub-application signature.

Answer

The firewall has not received the latest App-ID update.

Answer

SSL decryption is not configured.

Answer

A security rule is blocking the sub-application.

Question 4

Which THREE factors should be considered when troubleshooting App-ID misidentification? (Choose three.)

Accepted Answer

An application override is configured that misidentifies the app.. Option B is correct because an application override explicitly forces the firewall to classify traffic as a specific application, bypassing App-ID's signature-based identification. If the override is misconfigured, the firewall will consistently misidentify the traffic, leading to incorrect policy enforcement. This is a common cause of App-ID misidentification when administrators manually override the default identification process.

Answer

Packet size exceeds the maximum transmission unit.

Question 5

A global company uses a Palo Alto Networks firewall at its headquarters. They have a security policy that allows 'web-browsing' and 'ssl' for all users. Recently, they deployed a new custom web application for internal use that runs on TCP port 8443 with SSL. The application is not identified by App-ID as 'web-browsing' or 'ssl', but as 'unknown-tcp'. The security team wants to ensure that only this specific application is allowed, and all other unknown traffic is blocked. They have created a custom App-ID for the application using application override. However, after applying the override, the traffic is still shown as 'unknown-tcp' in logs. What is the most likely reason?

Accepted Answer

The security rule that allows the traffic does not include the custom application.. Option C is correct because the security rule that allows 'web-browsing' and 'ssl' does not automatically permit the custom application. Even though an application override was created to identify the custom application on TCP 8443, the security policy must explicitly include that custom application in the rule's 'Application' field. Without that, the firewall still matches the traffic against the existing rule, which only allows 'web-browsing' and 'ssl', so the traffic is denied and logged as 'unknown-tcp'.

Answer

SSL decryption is not enabled for the custom application.

Answer

The custom application needs to be added to the 'ssl' application group.

Answer

The application override was not committed.

Question 6

Which monitoring tool in Palo Alto Networks firewall provides real-time visibility into decryption statistics, such as the number of sessions decrypted and certificate errors?

Accepted Answer

Dashboard. The Dashboard in Palo Alto Networks firewall provides real-time visibility into decryption statistics, including the number of sessions decrypted, certificate errors, and decryption failures. This is accessible via the 'Decryption' widget on the Dashboard, which aggregates live data from the decryption engine without requiring log queries or report generation.

Answer

Policy Optimizer

Answer

Log Viewer

Answer

Reports

Question 7

An organization uses App-ID to allow 'web-browsing' but notices that some web traffic is being blocked. The traffic is HTTP over port 8080. What is a likely cause?

Accepted Answer

The security rule does not have Application set to 'web-browsing' for that traffic.. Option C is correct because if the security rule does not have 'web-browsing' set as the Application, the firewall will not allow HTTP traffic even if the port (8080) is permitted. App-ID identifies the application regardless of port, but the security policy must explicitly allow the application for the traffic to pass. In this case, the traffic is being blocked because the rule either has a different application or no application specified, so the firewall drops it by default.

Answer

The 'web-browsing' application does not include HTTP.

Answer

A custom application must be created for port 8080.

Answer

App-ID cannot identify HTTP over non-standard ports.

Question 8

Which TWO are capabilities of Content-ID? (Choose two.)

Accepted Answer

Blocking files by type (e.g., .exe, .pdf).. Content-ID is a Palo Alto Networks technology that extends App-ID by inspecting the actual content of traffic. It includes a file blocking capability that can block files by type (e.g., .exe, .pdf) based on the file's signature, not just its extension, providing granular control over file transfers. This is a core feature of Content-ID for data filtering.

Answer

Identifying the application regardless of port.

Answer

Applying QoS policies to applications.

Question 9

What is the most likely reason the traffic is being denied?

Accepted Answer

A threat prevention profile is blocking the application due to its 'evasive-behavior' characteristic.. Option B is correct because the question describes a scenario where traffic is denied despite the application being identified by App-ID. A threat prevention profile can block applications that exhibit 'evasive-behavior' characteristics, such as using non-standard ports or encryption to evade detection. This is a common security control in Palo Alto Networks firewalls to prevent malicious or evasive applications from bypassing policy.

Answer

The application is not actually matching the rule.

Answer

A DoS protection policy is blocking the traffic.

Answer

App-ID is incorrectly identifying the traffic.

Question 10

A company implements SSL Forward Proxy decryption. Users report that some internal applications fail to load after deployment. The firewall is configured with a CA-signed certificate for decryption. What is the most likely cause of the application failures?

Accepted Answer

The firewall's CA certificate is not installed in the trusted root store on user endpoints.. Option C is correct because SSL Forward Proxy decryption requires the firewall's CA certificate to be trusted by client endpoints. When the firewall generates a new certificate for the internal application's server, the client must trust the firewall's CA to avoid certificate validation errors. Without the CA in the trusted root store, browsers and applications will reject the connection, causing failures for internal applications that rely on SSL/TLS.

Answer

The decryption policy uses 'No Decrypt' for the internal application's URL category.

Answer

The decryption policy is set to 'Decrypt' for all traffic, causing performance bottlenecks.

Answer

The firewall is configured to decrypt traffic from the internal zone, but not the external zone.

Question 11

During a security audit, it is discovered that some internal hosts are using TLS 1.0, which is deprecated. The firewall is configured to decrypt SSL traffic. How can the administrator use the firewall to detect and report these connections without breaking them?

Accepted Answer

Configure a decryption policy rule with action 'Decrypt' and enable 'TLS Version Check' with action 'alert'.. Option A is correct because the firewall can decrypt TLS 1.0 traffic (action 'Decrypt') while using the 'TLS Version Check' feature set to 'alert' to detect and log the deprecated protocol without disrupting the connection. This allows the administrator to identify hosts using TLS 1.0 for reporting and remediation, while maintaining business continuity.

Answer

Configure a decryption policy rule with action 'No Decrypt' for TLS 1.0 traffic.

Answer

Use a Security policy rule to block TLS 1.0 traffic.

Answer

Configure a decryption policy rule with action 'Decrypt' and enable 'TLS Version Check' with action 'block'.

Question 12

Refer to the exhibit. An administrator notices a large number of decryption sessions. What is a valid conclusion based on the output?

Accepted Answer

There are a few sessions failing due to TLS version mismatch.. The exhibit shows decryption sessions with a 'TLS version mismatch' error, which indicates that the firewall is failing to establish a decryption session because the client and server are attempting to use different TLS versions (e.g., TLS 1.0 vs. TLS 1.2). This is a specific failure reason logged in the decryption session table, and the large number of such sessions confirms that many are failing due to this mismatch, not due to certificate errors or policy issues.

Answer

The firewall is rejecting many sessions due to certificate errors.

Answer

The decryption policy is not being hit because of low policy hits.

Answer

The current decryption session count is at its peak.

Question 13

Refer to the exhibit. A user in the trust zone accesses a banking site (category: financial-services). What action will the firewall take on this HTTPS session?

Accepted Answer

No Decrypt (bypass decryption). The firewall is configured with a decryption policy that matches the banking site (financial-services category) and has the action set to 'No Decrypt'. This action explicitly bypasses SSL/TLS decryption for the session, allowing the HTTPS traffic to pass through without inspection. The user in the trust zone accessing the site will therefore have the session proceed without decryption.

Answer

Error due to rule conflict

Answer

Block

Answer

Decrypt

Question 14

A company has a decryption policy that decrypts all outbound SSL traffic. Recently, users accessing a partner website receive a certificate warning. The partner uses a self-signed certificate. The firewall is configured with a CA-signed certificate for decryption. Which action should the firewall take?

Accepted Answer

The firewall will present the server's self-signed certificate to the client, causing a warning.. When a firewall is configured for SSL decryption with a CA-signed certificate, it acts as a man-in-the-middle. For outbound traffic to a server using a self-signed certificate, the firewall cannot validate the server's certificate against a trusted CA. It will present the server's self-signed certificate to the client, which the client's browser does not trust, causing a certificate warning.

Answer

The firewall will block the connection and generate an alert.

Answer

The firewall will decrypt the traffic using its own certificate and re-encrypt with the partner's certificate.

Answer

The firewall will automatically trust the self-signed certificate and pass traffic without decryption.

Question 15

A security engineer notices that HTTPS traffic to a critical business application is being decrypted and re-encrypted, causing performance issues. The application uses a certificate from a public CA. The engineer wants to minimize decryption overhead while still inspecting for threats. Which decryption policy configuration best achieves this?

Accepted Answer

Create a decryption policy rule with action 'No Decrypt' and enable 'Forward Trust Certificate' and 'Forward Untrust Certificate' with certificate status check.. Option C is correct because setting the action to 'No Decrypt' with a Forward Trust Certificate and Forward Untrust Certificate enabled, along with certificate status check, allows the firewall to validate the server certificate and forward the original encrypted traffic without decrypting it. This minimizes decryption overhead while still performing certificate inspection to detect threats like revoked or untrusted certificates, which is ideal for traffic from a public CA where decryption is not required for threat detection.

Answer

Create a decryption policy rule with action 'Decrypt' and a custom URL category for the application.

Answer

Create a decryption policy rule with action 'No Decrypt' and disable certificate status check.

Answer

Create a decryption policy rule with action 'Decrypt' and source zone set to 'Untrust'.

Question 16

An organization deploys SSL Forward Proxy decryption. They want to ensure that traffic to financial websites is not decrypted due to compliance requirements. Which decryption policy configuration should be used?

Accepted Answer

Create a decryption rule with action 'No Decrypt' for the URL category 'Financial Services'.. SSL Forward Proxy decryption rules are evaluated in order, and the first matching rule determines the action. To exclude financial websites from decryption, you must create a rule with action 'No Decrypt' that matches the 'Financial Services' URL category. This ensures traffic to those sites is not decrypted, meeting compliance requirements.

Answer

Create a decryption rule with action 'Decrypt' and destination zone 'Untrust'.

Answer

Create a decryption rule with action 'No Decrypt' for all traffic, then a rule above it to decrypt all other traffic.

Answer

Create a decryption rule with action 'Decrypt' for the URL category 'Financial Services'.

Question 17

A network administrator wants to monitor traffic that is not decrypted due to a 'No Decrypt' policy rule. Which log type would show that decryption was bypassed?

Accepted Answer

Tunnel Inspection logs. Tunnel Inspection logs are specifically designed to record traffic that bypasses decryption due to a 'No Decrypt' policy rule. When a decryption policy is set to 'No Decrypt', the firewall does not inspect the encrypted payload, but Tunnel Inspection logs capture metadata about the bypassed session, including the reason for bypass. This allows administrators to monitor and audit traffic that was not decrypted, ensuring visibility into policy exceptions.

Answer

URL Filtering logs

Answer

Threat logs

Answer

Traffic logs

Question 18

A company uses SSL Forward Proxy decryption. The firewall's decryption certificate expires. What immediate impact does this have on traffic?

Accepted Answer

Users receive certificate warnings when accessing HTTPS sites.. When the firewall's SSL Forward Proxy decryption certificate expires, the firewall can no longer present a valid certificate to clients during the SSL/TLS handshake. Browsers and applications will detect the expired certificate and display certificate warnings or errors to users, but the firewall may still attempt to decrypt traffic using the expired certificate, causing trust failures. This is the immediate impact because the firewall does not block traffic by default; it continues to proxy the connection, but the client rejects the invalid certificate.

Answer

The firewall logs a critical system alert.

Answer

Decryption stops working and all SSL traffic is blocked.

Answer

The firewall automatically renews the certificate from the CA.

Question 19

Which THREE of the following are valid actions for a decryption policy rule? (Choose three.)

Accepted Answer

No Decrypt. Option A is correct because 'No Decrypt' is a valid action in a decryption policy rule that explicitly excludes traffic from decryption, often used for traffic that cannot be decrypted (e.g., certificate pinning) or should not be inspected for compliance reasons. This action ensures the firewall forwards the traffic without attempting SSL/TLS interception.

Answer

Block

Answer

Forward

Question 20

Which TWO of the following are types of decryption supported by Palo Alto Networks firewalls? (Choose two.)

Accepted Answer

SSL Forward Proxy. SSL Forward Proxy is correct because it allows the firewall to decrypt outbound SSL/TLS traffic from internal clients to external servers, enabling inspection of encrypted content for threats and data filtering. This is a core decryption feature in Palo Alto Networks firewalls, distinct from inbound inspection.

Answer

SSH Proxy

Answer

TLS 1.3 Decryption

Answer

SSL Reverse Proxy