- A
Set up VPC peering with the instance's VPC.
Why wrong: VPC peering allows connectivity between VPCs, but the instance still has no external IP and SSH would require a bastion host without IAP.
- B
Create a Cloud NAT to allow inbound SSH.
Why wrong: Cloud NAT is for outbound traffic only.
- C
Add a firewall rule allowing SSH from any IP.
Why wrong: Without an external IP, traffic cannot reach the instance from the internet even with firewall rules.
- D
Use Identity-Aware Proxy (IAP) TCP forwarding.
IAP TCP forwarding establishes an encrypted tunnel to the instance via the IAP service.
Question 323 of 1,000
easyMultiple ChoiceObjective-mapped
Secure SSH Access to Compute Engine Instances Without Public IP Using IAP
This PCSE practice question tests your understanding of pcse exam topics. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 security engineer needs to provide secure SSH access to a Compute Engine instance that has no external IP address. What is the recommended method?
Quick Answer
The answer is Identity-Aware Proxy (IAP) TCP forwarding, which enables secure SSH access to a Compute Engine instance that has no external IP address. IAP TCP forwarding works by establishing a secure tunnel through Google’s edge network, allowing you to connect to the instance using its internal IP without exposing it to the public internet. This is the recommended method because it eliminates the need for a public IP, bastion host, or VPN, while integrating with Cloud IAM for fine-grained access control. On the Google Professional Cloud Security Engineer exam, this question tests your understanding of secure remote access patterns and common misconfigurations—a frequent trap is confusing Cloud NAT (which only supports outbound traffic) with inbound SSH, or assuming firewall rules alone can reach an instance with no external IP. Remember the key distinction: IAP TCP forwarding is for inbound administrative access, while Cloud NAT is strictly for outbound internet. A simple memory tip: “IAP In, NAT Out.”
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
✓
Use Identity-Aware Proxy (IAP) TCP forwarding.
Option D is correct because Identity-Aware Proxy (IAP) TCP forwarding allows SSH access to instances without external IP addresses. Option A is incorrect because VPC peering connects VPC networks, not provide SSH access. Option B is incorrect because Cloud NAT is for outbound internet access, not inbound SSH. Option C is incorrect because a firewall rule allowing SSH from any IP would still require the instance to have an external IP address.
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.
- ✗
Set up VPC peering with the instance's VPC.
Why it's wrong here
VPC peering allows connectivity between VPCs, but the instance still has no external IP and SSH would require a bastion host without IAP.
- ✗
Create a Cloud NAT to allow inbound SSH.
Why it's wrong here
Cloud NAT is for outbound traffic only.
- ✗
Add a firewall rule allowing SSH from any IP.
Why it's wrong here
Without an external IP, traffic cannot reach the instance from the internet even with firewall rules.
- ✓
Use Identity-Aware Proxy (IAP) TCP forwarding.
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 company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
Visual reference
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 PCSE NAT questions on configuration and troubleshooting.
Related practice questions
Related PCSE practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Configuring Access Within a Cloud Solution Environment practice questions
Practise PCSE questions linked to Configuring Access Within a Cloud Solution Environment.
Ensuring Data Protection practice questions
Practise PCSE questions linked to Ensuring Data Protection.
Managing Operations in a Cloud Solution Environment practice questions
Practise PCSE questions linked to Managing Operations in a Cloud Solution Environment.
Configuring Network Security practice questions
Practise PCSE questions linked to Configuring Network Security.
Supporting Compliance Requirements practice questions
Practise PCSE questions linked to Supporting Compliance Requirements.
PCSE fundamentals practice questions
Practise PCSE questions linked to PCSE fundamentals.
PCSE scenario practice questions
Practise PCSE questions linked to PCSE scenario.
PCSE troubleshooting practice questions
Practise PCSE questions linked to PCSE troubleshooting.
Practice this exam
Start a free PCSE practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this PCSE question test?
Static NAT maps one inside address to one outside address.
What is the correct answer to this question?
The correct answer is: Use Identity-Aware Proxy (IAP) TCP forwarding. — Option D is correct because Identity-Aware Proxy (IAP) TCP forwarding allows SSH access to instances without external IP addresses. Option A is incorrect because VPC peering connects VPC networks, not provide SSH access. Option B is incorrect because Cloud NAT is for outbound internet access, not inbound SSH. Option C is incorrect because a firewall rule allowing SSH from any IP would still require the instance to have an external IP address.
What should I do if I get this PCSE 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 PCSE NAT questions on configuration and troubleshooting.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Keep practising
More PCSE practice questions
- Match each encryption scope to its description.
- Drag and drop the steps to set up a Private Google Access for on-premises hosts using Private Service Connect in the cor…
- A company is designing a CI/CD pipeline using Cloud Build. Security requirements mandate that the pipeline deploy only t…
- A company must implement data residency requirements that prohibit storing data outside the European Union. They are usi…
- A company wants to allow employees to access a web application running on Google Kubernetes Engine (GKE) using their cor…
- A company is deploying a multi-tier application on Google Cloud. The web tier must be accessible from the internet, whil…
Last reviewed: Jun 24, 2026
This PCSE 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 PCSE exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.