PCNSE Practice Question: Managing Troubleshooting and High Availability
A company has deployed two PA-3220 firewalls in an active/passive high availability configuration. During normal operation, the active firewall (FW-A) handles all traffic. The network team notices that after a brief power outage, both firewalls report as active in the HA pair, causing network instability. The administrator needs to resolve this issue and prevent it from recurring. Which course of action should the administrator take?
⚠ Common exam trap
A common mix-up: candidates assume rebooting or resetting the HA state (Option A) is sufficient, but they overlook the need for preemption to automatically resolve the split-brain condition after a power failure, which is a common cause of HA instability in production environments.
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
✓
Configure the HA mode with the 'preemptive' option and set the device priority higher on the intended active firewall.
Configuring the HA mode with the 'preemptive' option ensures that when both firewalls recover from a power outage, the firewall with the higher device priority (the intended active unit) will automatically preempt the other and become active. Without preemption, both firewalls may come up as active if they lose HA heartbeat synchronization during the outage, leading to a split-brain scenario. Setting the device priority higher on FW-A guarantees it is preferred as the active unit upon recovery.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Reboot both firewalls simultaneously to reset the HA state.
Why it's wrong here
Rebooting is a temporary workaround but does not prevent recurrence; the configuration issue remains.
- ✗
Disable link speed and duplex settings on the HA interfaces to force a failover.
Why it's wrong here
Changing link settings can cause interface instability and is not a recommended method to resolve HA state issues.
- ✓
Configure the HA mode with the 'preemptive' option and set the device priority higher on the intended active firewall.
Why this is correct
Preemptive ensures the higher-priority device becomes active after recovery, preventing both firewalls from staying active.
- ✗
Set the HA mode to 'active/active' to allow both firewalls to process traffic.
Why it's wrong here
Active/active mode is not appropriate for this situation and would not resolve the split active issue; it requires different configuration.
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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.