PCNSE Deploy and Configure Firewalls Practice Question
A global company uses a pair of PAN-220 firewalls in an active/passive HA configuration at its headquarters. The firewalls have multiple virtual routers and dozens of zones. Recently, a network upgrade changed the physical topology: a new switch was placed between the firewalls and the ISP routers. After the upgrade, the passive firewall continuously shows 'suspended' state. The HA control link (HA1) and data link (HA2) are on separate dedicated interfaces. The Active firewall logs show: 'HA monitor peer unreachable' every few seconds. The engineer has verified IP connectivity between the HA interfaces using ping from the active to the passive HA1 IP. What is the most likely cause of the HA state issue?
⚠ Common exam trap
Test-takers frequently assume ping success between HA interfaces guarantees HA keepalive success, but HA keepalives are more sensitive to jitter and latency than ICMP, and the 'suspended' state specifically indicates a keepalive timeout rather than a link or encryption failure.
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
✓
The new switch introduces latency or jitter that exceeds the HA keepalive timeout
The 'HA monitor peer unreachable' log combined with a 'suspended' passive firewall, despite confirmed IP connectivity on HA1, points to a failure in the HA keepalive mechanism. The new switch introduces latency or jitter that causes keepalive packets to arrive outside the default 2-second hello interval and 8-second dead-interval, triggering the active firewall to declare the peer unreachable. This is a classic issue when a switch is inserted into the HA path without adjusting the HA keepalive timers or ensuring the switch provides low-latency forwarding.
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 HA2 link is misconfigured or unplugged
Why it's wrong here
HA2 is for data; the 'suspended' state is driven by HA1 heartbeat failures.
- ✓
The new switch introduces latency or jitter that exceeds the HA keepalive timeout
Why this is correct
HA keepalives are time-sensitive; a switch can add latency that makes the passive appear dead, even if basic connectivity exists.
- ✗
The session table on the active firewall is full, preventing HA keepalives
Why it's wrong here
Session table fullness may cause performance issues but does not directly stop HA keepalive packets.
- ✗
The HA1 encryption setting is mismatched between the two firewalls
Why it's wrong here
Mismatched encryption would show a different log, not simply 'peer unreachable'.
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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.