The answer is that the client does not trust the certificate authority that signed the portal certificate. This is the most likely cause because a TLS handshake failed error in the GlobalProtect logs, combined with successful network reachability to the portal IP, points directly to a certificate validation problem rather than a connectivity issue. During the SSL/TLS handshake, the GlobalProtect client receives the portal’s certificate and checks whether its issuing CA is in the client’s trusted root store; if the internal CA is not trusted, the client rejects the certificate and aborts the handshake. On the PCNSE exam, this scenario tests your understanding of how certificate trust chains affect GlobalProtect portal authentication, and a common trap is to focus on network misconfigurations when the real issue is client-side trust. Remember the memory tip: “Reachability is fine, handshake fails—check the CA, not the wires.”
PCNSE Troubleshoot Practice Question
This PCNSE practice question tests your understanding of troubleshoot. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
An engineer is troubleshooting an issue where GlobalProtect users are unable to connect to the portal. The portal is configured with a certificate signed by an internal CA. Users can reach the portal's IP address from the internet, but the connection fails. The firewall log shows 'TLS handshake failed'. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The client does not trust the certificate authority that signed the portal certificate
The firewall log shows 'TLS handshake failed', which indicates that the SSL/TLS negotiation between the GlobalProtect client and the portal failed. Since users can reach the portal's IP address from the internet, the issue is not network connectivity but certificate validation. The most common cause is that the client does not trust the internal CA that signed the portal certificate, so the client rejects the certificate during the TLS handshake, causing the failure.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The portal service is not running
Why it's wrong here
If it were not running, the IP would not be reachable.
✗
The portal's IP address is not routable from the internet
Why it's wrong here
Users can reach the IP, so routing works.
✗
The portal certificate's subject name does not match the portal URL
Why it's wrong here
If it matched, but the CA is not trusted, the handshake still fails.
✓
The client does not trust the certificate authority that signed the portal certificate
Why this is correct
The TLS handshake fails because the client cannot verify the server certificate.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse a certificate name mismatch (subject name vs. URL) with a trust issue, but the 'TLS handshake failed' log entry specifically points to a failure in the certificate chain validation, not a name mismatch, which would produce a different error or warning.
Detailed technical explanation
How to think about this question
During the TLS handshake, the server presents its certificate, and the client verifies the certificate chain against its trusted root store. If the client does not trust the issuing CA (e.g., because the CA certificate is not installed in the client's trust store), the client aborts the handshake with a fatal alert, which the firewall logs as 'TLS handshake failed'. In GlobalProtect, the portal certificate must be trusted by the client device; for internal CAs, this often requires deploying the CA certificate via Group Policy or MDM. The firewall log does not differentiate between a certificate chain validation failure and other TLS errors, so the symptom is a generic handshake failure.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the PCNSE exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Troubleshoot — This question tests Troubleshoot — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The client does not trust the certificate authority that signed the portal certificate — The firewall log shows 'TLS handshake failed', which indicates that the SSL/TLS negotiation between the GlobalProtect client and the portal failed. Since users can reach the portal's IP address from the internet, the issue is not network connectivity but certificate validation. The most common cause is that the client does not trust the internal CA that signed the portal certificate, so the client rejects the certificate during the TLS handshake, causing the failure.
What should I do if I get this PCNSE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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