Networking is one of the most important pillars of any AWS architecture. Whether you’re designing a secure cloud environment or building large-scale applications, having a clear understanding of AWS networking services such as transit gateway, PrivateLink, VPC peering, and hybrid connectivity is crucial. These topics are regularly covered in technical interviews, so being confident in them can make a major difference in your success.
In this blog, you’ll find a complete set of AWS networking interview questions and answers written in a simple and easy-to-understand format. The focus is on real interview-style responses that help you explain concepts clearly. This guide is great for both beginners and professionals looking to strengthen their AWS networking knowledge.
AWS Networking Interview Questions and Answers
Question 1. What is AWS Transit Gateway?
Answer: AWS transit gateway is a network transit hub that enables you to connect multiple VPCs and on-premises networks using a central gateway. Instead of creating multiple VPC peering connections, transit gateway simplifies connectivity with a hub-and-spoke model. It also supports routing controls, scalability, and inter-region attachments, making it a preferred choice for multi-VPC architectures.
Question 2. How is Transit Gateway different from VPC Peering?
Answer: VPC peering creates a direct connection between two VPCs but does not scale well with many VPCs. Transit gateway provides centralized routing and can connect thousands of VPCs and on-premises networks. Another difference is that VPC peering does not support transitive routing, whereas transit gateway allows traffic to pass between networks through itself.
Question 3. What is AWS PrivateLink and when should you use it?
Answer: AWS PrivateLink allows private connectivity between VPCs and AWS services or third-party applications without exposing traffic to the public internet. It’s useful for securing communication, reducing attack exposure, and supporting compliance requirements. PrivateLink uses interface endpoints powered by elastic network interfaces inside your VPC.
Question 4. How does PrivateLink differ from VPC Peering?
Answer: PrivateLink enables access to services through private endpoints but does not allow full VPC-to-VPC communication. VPC peering, on the other hand, allows bidirectional communication across entire VPC networks. So, PrivateLink is best for consuming services privately, while peering is useful for broader connectivity between two VPCs.
Question 5. What is hybrid connectivity in AWS?
Answer: Hybrid connectivity is the ability to connect on-premises environments with AWS networks. It enables enterprises to extend their physical infrastructure into the cloud. AWS offers services like VPN, Direct Connect, transit gateway, and SD-WAN integrations to ensure secure and reliable hybrid connections.
Question 6. When should you use AWS Direct Connect over a VPN connection?
Answer: Direct Connect provides a dedicated physical connection with better bandwidth performance and lower consistent latency. VPN connectivity uses the public internet, making it easier to set up but less reliable for high-traffic workloads. Organizations choose Direct Connect when they need secure, stable, high-speed hybrid connectivity.
Question 7. What are the main advantages of AWS Transit Gateway?
Answer:
- Centralized network management
- Supports thousands of VPCs
- Enables inter-region routing
- Allows hybrid connectivity with Direct Connect/VPN
- Reduces complexity by eliminating multiple peering links
Question 8. Can Transit Gateway be used for inter-region connectivity?
Answer: Yes, transit gateway supports inter-region attachments. This helps create a globally connected network with consistent control using a central hub, improving the architecture for distributed applications.
Question 9. What is a VPC Endpoint and how does it improve security?
Answer: A VPC endpoint provides private access to AWS services like S3 and DynamoDB without sending traffic over the public internet. This enhances both security and compliance by preventing exposure to external networks and removing dependency on NAT gateways or internet gateways.
Question 10. When should you use VPC Peering?
Answer: You should use VPC peering when you need full communication between two VPCs with low latency and no bandwidth limitations. It’s suitable for workloads requiring private interaction between tightly related environments.
Question 11. What limitations exist in VPC Peering?
Answer:
- No transitive routing
- Cannot reference security groups across regions (unless inter-region peering supported)
- Complex to scale when multiple VPCs are involved
Question 12. How does Transit Gateway pricing work?
Answer: Cost is based on three factors:
- The number of attachments
- The amount of data processed
- Inter-region traffic charges if enabled
Question 13. Why is AWS PrivateLink recommended for SaaS providers?
Answer: PrivateLink gives SaaS providers a secure way to expose services to customers. It isolates traffic inside AWS networking, removes public exposure, and supports enterprise security requirements—making integration safer and simpler.
Question 14. What is the difference between a Virtual Private Gateway and a Transit Gateway?
Answer: A virtual private gateway is used to connect a single VPC to on-premises networks through VPN or Direct Connect. Transit gateway can connect multiple VPCs and on-prem networks at scale, making it the newer and more scalable connectivity solution.
Question 15. Can Direct Connect and Transit Gateway work together?
Answer: Yes, Direct Connect can attach to transit gateway, offering better performance and centralized routing for hybrid connectivity use cases like data center extensions and large corporate networks.
Question 16. What are AWS Site-to-Site VPNs used for?
Answer: They allow encrypted communication over the public internet between on-premises data centers and AWS VPCs. They are cost-effective for initial or temporary hybrid connectivity.
Question 17. How do Network ACLs differ from Security Groups?
Answer: Network ACLs operate at the subnet level and are stateless, meaning return traffic must be explicitly allowed. Security groups operate at the instance level and are stateful—when inbound traffic is allowed, response traffic is automatically permitted.
Question 18. What is the purpose of Route Tables in AWS networking?
Answer: Route tables determine how network traffic flows within and outside a VPC. Every subnet must be associated with a route table that instructs how traffic should be forwarded.
Question 19. What is a Transit Gateway Route Table?
Answer: It controls the routing between attachments such as VPCs, VPNs, or Direct Connect links. Admins can isolate routing domains using multiple route tables for stricter network segmentation.
Question 20. Why do companies adopt multi-VPC architectures?
Answer:
- Workload isolation
- Compliance requirements
- Separate teams or environments (dev, staging, prod)
- Scaling connectivity across regions and accounts
Conclusion
Understanding AWS networking is essential for building secure, scalable, and high-performance cloud environments. Services like transit gateway, PrivateLink, VPC peering, and hybrid connectivity form the foundation of modern cloud networking designs. With this list of interview questions and answers, you’re now better prepared for technical interviews focused on AWS networking roles. Keep practicing these concepts, and you’ll gain confidence to explain real-world architecture scenarios effectively.
