PCNSE Split Brain Practice Question
A network engineer is troubleshooting an HA pair where both firewalls show as 'active' in the HA state. What is this condition called?
⚠ Common exam trap
The trap is that candidates may think both firewalls being active indicates Active/Active mode, but in an active/passive pair, this is a split-brain failure condition.
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
✓
Split brain
In a Palo Alto Networks active/passive HA configuration, if the heartbeat fails, both firewalls assume the other is down and both transition to 'active' state. This unintended condition is called split brain. It is not a valid configuration like Active/Active, which is intentionally configured and requires separate virtual routers or security zones.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Link failure
Why it's wrong here
Link failure is when a monitored link goes down, triggering failover, not both firewalls being active.
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Active/Active
Why it's wrong here
Active/Active is a valid configuration where both firewalls are active by design, not a troubleshooting condition.
- ✗
Passive/Passive
Why it's wrong here
Passive/Passive would mean both are passive, which is not the scenario described.
- ✓
Split brain
Why this is correct
Correct. When both firewalls in an active/passive pair show active due to loss of heartbeat, this is called split brain.
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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.