SCS-C02 Infrastructure Security Practice Question
A security engineer is designing a VPC with public and private subnets. The application must be able to send outbound traffic to the internet, but inbound traffic from the internet must be blocked except for a single HTTP load balancer. The application also needs to access an S3 bucket in the same AWS region. Which combination of VPC components meets these requirements? (Choose two.)
⚠ Common exam trap
Many exam-takers choose an Internet Gateway (Option D) thinking it can be restricted via security groups or NACLs, but an Internet Gateway itself does not filter traffic—it simply enables bidirectional routing, and blocking inbound traffic requires additional controls like a NAT Gateway or a stateful firewall, which is not the intended design for private subnets.
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
✓
NAT Gateway in a public subnet
A NAT Gateway in a public subnet allows instances in private subnets to initiate outbound traffic to the internet (e.g., for software updates or API calls) while blocking unsolicited inbound connections. This satisfies the requirement for outbound internet access without exposing private instances directly.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
S3 Interface Endpoint in the VPC
Why it's wrong here
S3 does not support Interface Endpoints; only Gateway Endpoints are used.
- ✗
VPC Peering to a shared services VPC
Why it's wrong here
Not required for S3 access.
- ✓
NAT Gateway in a public subnet
Why this is correct
Allows outbound internet to EC2 instances in private subnets.
- ✗
Internet Gateway attached to the VPC
Why it's wrong here
Would allow inbound from internet, which is not desired.
- ✓
S3 Gateway Endpoint in the VPC
Why this is correct
Provides private connectivity to S3 without internet.
Visual reference
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
Go deeper
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SCS-C02 practice question is part of Courseiva's free Amazon Web Services 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 SCS-C02 exam.