- A
The firewall's asymmetric routing detection is dropping traffic; disable asymmetric routing enforcement.
Why wrong: Asymmetric routing detection affects return traffic, not outbound path selection.
- B
The HA configuration has ECMP disabled; enable ECMP in the dataplane settings on the active firewall.
ECMP allows the firewall to use multiple equal-cost routes for load balancing; it must be enabled.
- C
The BGP configuration on the passive firewall is not identical to the active one; apply the same BGP configuration to both.
Why wrong: The passive firewall's BGP config does not impact the active firewall's routing table.
- D
The passive firewall is not advertising routes to the ISPs because HA state synchronization is not enabled; enable state synchronization.
Why wrong: State sync does not affect route advertisement; BGP peers on the passive firewall are independent.
PCNSE Deploy and Configure Firewalls Practice Question
This PCNSE practice question tests your understanding of deploy and configure firewalls. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company has deployed a Palo Alto Networks firewall in an active/passive high-availability (HA) pair. The firewall uses BGP for dynamic routing with two upstream ISPs to provide load-balanced internet connectivity. After an HA failover event, the network team notices that outbound traffic from internal hosts is now using only one of the two ISPs, even though BGP sessions are established on both firewalls and the passive firewall has learned the same routes as the active one. The security policy permits all outbound traffic. No changes were made to the BGP configuration. Which of the following is the most likely cause of this behavior, and what is the appropriate solution?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 HA configuration has ECMP disabled; enable ECMP in the dataplane settings on the active firewall.
Option C is correct because ECMP (Equal Cost Multi-Path) routing must be enabled on the active firewall to use multiple BGP-learned default routes for load balancing. After failover, if ECMP is disabled, only one best path is installed, causing traffic to use a single ISP. Option A is incorrect because state synchronization deals with session state, not routing decisions. Option B is incorrect because the passive firewall's BGP configuration does not affect routing on the active firewall unless it becomes active. Option D is incorrect because asymmetric routing detection would affect return traffic, not the outbound path selection.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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 firewall's asymmetric routing detection is dropping traffic; disable asymmetric routing enforcement.
Why it's wrong here
Asymmetric routing detection affects return traffic, not outbound path selection.
- ✓
The HA configuration has ECMP disabled; enable ECMP in the dataplane settings on the active firewall.
Why this is correct
ECMP allows the firewall to use multiple equal-cost routes for load balancing; it must be enabled.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
- ✗
The BGP configuration on the passive firewall is not identical to the active one; apply the same BGP configuration to both.
- ✗
The passive firewall is not advertising routes to the ISPs because HA state synchronization is not enabled; enable state synchronization.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Got this wrong? Here's your next step.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related PCNSE NAT questions on configuration and troubleshooting.
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FAQ
Questions learners often ask
What does this PCNSE question test?
Deploy and Configure Firewalls — This question tests Deploy and Configure Firewalls — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: The HA configuration has ECMP disabled; enable ECMP in the dataplane settings on the active firewall. — Option C is correct because ECMP (Equal Cost Multi-Path) routing must be enabled on the active firewall to use multiple BGP-learned default routes for load balancing. After failover, if ECMP is disabled, only one best path is installed, causing traffic to use a single ISP. Option A is incorrect because state synchronization deals with session state, not routing decisions. Option B is incorrect because the passive firewall's BGP configuration does not affect routing on the active firewall unless it becomes active. Option D is incorrect because asymmetric routing detection would affect return traffic, not the outbound path selection.
What should I do if I get this PCNSE question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related PCNSE NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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Last reviewed: Jun 24, 2026
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.
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