PCNSE Practice Question: Managing Troubleshooting and High Availability
A firewall in an HA pair is being upgraded. The administrator wants to minimize traffic loss. What is the recommended procedure for upgrading the passive firewall in an active/passive pair?
⚠ Common exam trap
It's easy for candidates to assume upgrading the active firewall first is safer because it is the primary device, but this ignores the fact that the passive firewall must be upgraded and ready to take over before the active firewall is touched to avoid traffic loss.
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
✓
Upgrade the passive firewall, failover to it, then upgrade the original active
In an active/passive HA pair, the passive firewall is upgraded first while the active firewall continues to handle traffic. After the passive firewall is upgraded and rebooted, an administrative failover is performed to make it the new active firewall, minimizing traffic loss. The original active firewall is then upgraded, ensuring there is always a firewall processing traffic during the upgrade process.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Upgrade the active firewall first, then failover to the passive
Why it's wrong here
Upgrading the active node first takes down the only forwarding device, causing the traffic loss the administrator wants to avoid. Active-first suits maintenance windows with accepted downtime. Upgrading the passive node first keeps the active firewall serving traffic until failover.
- ✓
Upgrade the passive firewall, failover to it, then upgrade the original active
Why this is correct
Upgrading the passive node first keeps the active firewall forwarding traffic, then a failover promotes the upgraded unit so it carries sessions while the original active is upgraded. This staged approach satisfies the minimise-traffic-loss constraint without taking both nodes offline simultaneously.
- ✗
Suspend HA, upgrade both, then re-enable HA
Why it's wrong here
Suspending HA and upgrading both nodes leaves no peer to absorb traffic, so an outage is unavoidable. This suits isolated pairs with no service commitment. The passive-first approach keeps the active node forwarding while its peer is upgraded.
- ✗
Upgrade both firewalls simultaneously after disconnecting HA links
Why it's wrong here
Disconnecting HA links removes the redundancy that protects traffic during the upgrade, guaranteeing an outage window. Simultaneous upgrades suit lab rebuilds where no live traffic exists. The passive-first sequence preserves the active node's forwarding throughout.
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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.