What are VPC endpoints, and what is the difference between Gateway and Interface endpoints?
AWS · Basic level
Answer
VPC endpoints keep traffic to supported AWS services on private AWS networking instead of the public internet. Gateway endpoints are mainly for S3 and DynamoDB through route tables; Interface endpoints use PrivateLink ENIs for many AWS and partner services.
Technical explanation
Endpoint policies and private DNS are as important as endpoint creation because they control what resources can be reached privately.
In AWS networking, always separate placement, routing, and filtering: subnets place resources, route tables decide next hops, and SG/NACL rules filter traffic.
Design for failure domains by spreading public, private, and data subnets across multiple AZs and avoiding single-AZ dependencies where production availability matters.
Troubleshooting should follow packet flow: source, SG, NACL, route table, endpoint/NAT/IGW/TGW, destination SG, and service listener.
Hands-on example
1. Create a sandbox VPC with two AZs, public subnets, private subnets, route tables, IGW, NAT Gateway, security groups, and one VPC endpoint relevant to the topic.
2. Deploy a small test instance or pod in the correct subnet and validate routing with curl, traceroute where allowed, and VPC Flow Logs.
3. Change one control at a time - route, SG, NACL, endpoint policy, NAT, or TGW route - and observe exactly how connectivity changes.
4. Document the final production pattern as an architecture diagram plus a troubleshooting checklist.
Check how well your resume matches the role with our free resume checker— match score, ATS check, and the skills you're missing.
More AWS interview questions
- What is the AWS shared responsibility model, and where is the line between AWS and the customer?
- Explain the difference between a Region, an Availability Zone, and an Edge Location.
- What is a VPC, and what are its core components (subnets, route tables, IGW, NAT)?
- Difference between a public and a private subnet, and how does each reach the internet?
- What is the difference between a Security Group and a Network ACL?
- Are Security Groups stateful or stateless? What about NACLs?
- What is an Internet Gateway versus a NAT Gateway, and when do you need each?
- How does a NAT Gateway differ from a NAT instance?