- A
One VPC has a custom route for 0.0.0.0/0 pointing to a NAT gateway.
Why wrong: This is common and does not directly cause asymmetric routing between the peered VPCs.
- B
One VPC has a static route pointing to the peering connection, and the other has a static route pointing to a VPN tunnel.
This mismatch in next hops causes asymmetric routing.
- C
Dynamic routing mode is set to regional on both sides.
Why wrong: Regional routing mode does not cause asymmetric routing by itself.
- D
Both VPCs have default internet gateways.
Why wrong: Default internet gateways do not affect inter-VPC routing.
Question 474 of 1,000
PCNE Practice Question: Managing, Monitoring, and Optimising Network Operations
This PCNE practice question tests your understanding of managing, monitoring, and optimising network operations. 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 two VPC networks connected via VPC Network Peering. They observe asymmetric routing causing connectivity issues. Which configuration is most likely to be the root cause?
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
✓
One VPC has a static route pointing to the peering connection, and the other has a static route pointing to a VPN tunnel.
Asymmetric routing in VPC peering often occurs when both sides have overlapping or conflicting routes, such as custom static routes that point to different next hops. VPC peering requires symmetric routing.
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.
- ✗
One VPC has a custom route for 0.0.0.0/0 pointing to a NAT gateway.
Why it's wrong here
This is common and does not directly cause asymmetric routing between the peered VPCs.
- ✓
One VPC has a static route pointing to the peering connection, and the other has a static route pointing to a VPN tunnel.
Why this is correct
This mismatch in next hops causes asymmetric routing.
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.
- ✗
Dynamic routing mode is set to regional on both sides.
Why it's wrong here
Regional routing mode does not cause asymmetric routing by itself.
- ✗
Both VPCs have default internet gateways.
Why it's wrong here
Default internet gateways do not affect inter-VPC routing.
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 healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
Quick reference
Asymmetric Encryption Algorithm Comparison
| Algorithm | Key Exchange | Signatures | Equivalent Security Key | Notes |
|---|---|---|---|---|
| RSA-3072 | Yes | Yes | 128-bit | Widely deployed; slow for bulk data |
| ECDSA P-256 | No | Yes | 128-bit | Fast signatures; standard TLS certs |
| ECDH / ECDHE | Yes | No | 128-bit | Perfect forward secrecy in TLS 1.3 |
| DH / DHE | Yes | No | 128-bit (3072-bit key) | Replaced by ECDHE in modern TLS |
| Ed25519 | No | Yes | ~128-bit | SSH keys, modern PKI |
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 PCNE NAT questions on configuration and troubleshooting.
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Managing, Monitoring, and Optimising Network Operations — study guide chapter
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FAQ
Questions learners often ask
What does this PCNE question test?
Managing, Monitoring, and Optimising Network Operations — This question tests Managing, Monitoring, and Optimising Network Operations — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: One VPC has a static route pointing to the peering connection, and the other has a static route pointing to a VPN tunnel. — Asymmetric routing in VPC peering often occurs when both sides have overlapping or conflicting routes, such as custom static routes that point to different next hops. VPC peering requires symmetric routing.
What should I do if I get this PCNE 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 PCNE 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: Jul 4, 2026
This PCNE practice question is part of Courseiva's free Google Cloud 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 PCNE exam.
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