PCNSE Practice Question: Managing Troubleshooting and High Availability
A large enterprise uses a pair of PA-5250 firewalls in an active/passive high availability configuration to protect their data center. The firewalls are connected to two upstream switches via aggregate Ethernet (AE) interfaces. The network team recently replaced the upstream switches, and since then, the passive firewall has gone into a 'non-functional' state. The active firewall shows no issues. The HA1 link is a direct cable connection between the firewalls, and HA2 is an out-of-band dedicated link. The administrative status of both firewalls is 'active-active' in the HA monitoring, but only one firewall is actually forwarding traffic. The team needs to restore proper HA operation. Which action should the team take first?
⚠ Common exam trap
Candidates often assume the passive firewall's 'non-functional' state is caused by HA link issues (HA1 or HA2) or session synchronization failures, when in fact it is typically due to path monitoring detecting a failed interface on the passive node.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Review the path monitoring configuration on both firewalls to ensure that the AE link to the new switches is correctly monitored for failover.
Path monitoring is used in active/passive HA to detect failures of monitored interfaces (like the AE links to the new switches). If the passive firewall's path monitoring configuration does not match the new switch interfaces or if the monitored AE link is down, the passive firewall will enter a 'non-functional' state to prevent it from becoming active with a broken path. The active firewall remains unaffected because it is already forwarding traffic and its path monitoring status is healthy.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Verify the physical connectivity and configuration of the HA2 link, as session synchronization failure can cause the passive node to be non-functional.
Why it's wrong here
HA2 is for session sync; its failure typically causes sync issues but not a 'non-functional' state. The link is a dedicated out-of-band connection, so it is unlikely to be the cause.
- ✗
Reboot the passive firewall to attempt to re-establish HA communication.
Why it's wrong here
Rebooting is disruptive and does not address the underlying configuration issue that caused the non-functional state.
- ✗
Check the logs on the passive firewall for new critical events during the switch replacement.
Why it's wrong here
While logs are useful, this is a secondary step; the most likely issue is path monitoring misconfiguration triggered by the switch replacement.
- ✓
Review the path monitoring configuration on both firewalls to ensure that the AE link to the new switches is correctly monitored for failover.
Why this is correct
Path monitoring checks data plane connectivity; if the monitored interface is down or misconfigured, the passive firewall goes non-functional. The switch replacement likely altered link characteristics, making the monitored path appear failed.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCNSE practice question is part of Courseiva's free Palo Alto Networks certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCNSE exam.