Interface VPC endpoints are a powerful networking feature in AWS that enable private connectivity between your Virtual Private Cloud (VPC) and supported AWS services, as well as third-party services hosted on AWS PrivateLink. Unlike Gateway endpoints, which are available only for S3 and DynamoDB, I…Interface VPC endpoints are a powerful networking feature in AWS that enable private connectivity between your Virtual Private Cloud (VPC) and supported AWS services, as well as third-party services hosted on AWS PrivateLink. Unlike Gateway endpoints, which are available only for S3 and DynamoDB, Interface endpoints support a wide range of AWS services including CloudWatch, SNS, SQS, EC2 API, Systems Manager, and many more.
When you create an Interface VPC endpoint, AWS provisions an Elastic Network Interface (ENI) with a private IP address in your specified subnets. This ENI serves as an entry point for traffic destined to the supported service. The traffic between your VPC and the AWS service travels entirely within the Amazon network, never traversing the public internet.
Key characteristics of Interface VPC endpoints include:
1. **Private DNS**: When enabled, the endpoint automatically resolves the service's default DNS hostname to the private IP address of the endpoint ENI, allowing applications to connect to services using standard endpoints.
2. **Security Groups**: You can attach security groups to Interface endpoints to control inbound and outbound traffic, providing granular network-level security.
3. **Availability Zones**: Interface endpoints can be deployed across multiple Availability Zones for high availability and redundancy.
4. **Pricing**: You pay hourly charges for each endpoint and data processing fees for data transferred through the endpoint.
5. **VPC Endpoint Policies**: You can attach IAM resource policies to endpoints to control which principals can use the endpoint to access services.
For SysOps administrators, Interface endpoints are essential for creating secure architectures where resources in private subnets need to access AWS services. They eliminate the need for NAT gateways, internet gateways, or VPN connections when accessing supported services, reducing costs and enhancing security posture while maintaining network isolation.
Interface VPC Endpoints, also known as AWS PrivateLink, are elastic network interfaces (ENIs) with private IP addresses that serve as entry points for traffic destined to supported AWS services or VPC endpoint services. They enable private connectivity between your VPC and AWS services, keeping all network traffic within the AWS network.
Why are Interface VPC Endpoints Important?
• Enhanced Security: Traffic between your VPC and AWS services stays within the Amazon network, never traversing the public internet • Reduced Data Transfer Costs: Eliminates the need for NAT gateways or internet gateways for accessing AWS services • Compliance Requirements: Helps meet regulatory requirements that mandate private network connectivity • Lower Latency: Private connectivity typically provides more consistent network performance • Simplified Network Architecture: Reduces the complexity of network configurations
How Interface VPC Endpoints Work
1. ENI Creation: When you create an interface endpoint, AWS creates an ENI in your specified subnet(s) 2. Private IP Assignment: Each ENI receives a private IP address from your subnet's IP range 3. DNS Resolution: AWS creates endpoint-specific DNS entries that resolve to the private IP addresses 4. Security Groups: You attach security groups to control traffic to and from the endpoint 5. Traffic Flow: Applications connect to the endpoint's private IP, and traffic is routed through the AWS network
Key Components: • Endpoint Network Interfaces: The actual ENIs created in your subnets • Private DNS: Optional setting that overrides default service DNS with endpoint DNS • Security Groups: Required to control inbound and outbound traffic • Endpoint Policies: IAM resource policies that control access to the service
Supported Services
Interface endpoints support numerous AWS services including: • Amazon EC2 API • Amazon SNS • Amazon SQS • AWS Systems Manager • Amazon CloudWatch • AWS Secrets Manager • Amazon Kinesis • And many more
Interface vs Gateway Endpoints
Interface Endpoints: • Use ENIs with private IPs • Support many AWS services • Require security groups • Have hourly and data processing charges
Gateway Endpoints: • Use route table entries • Support only S3 and DynamoDB • No additional charges • Cannot be extended to on-premises
Exam Tips: Answering Questions on Interface VPC Endpoints
1. Identify the Use Case: When a question mentions private connectivity to AWS services, keeping traffic off the public internet, or AWS PrivateLink, think interface endpoints
2. Remember Security Group Requirement: Interface endpoints require security groups - if a question mentions controlling access at the network level, security groups are the answer
3. DNS Considerations: Questions about resolving AWS service endpoints to private IPs typically involve enabling Private DNS on the interface endpoint
4. Cost Awareness: Interface endpoints have hourly charges plus data processing fees - relevant for cost optimization questions
5. Subnet Placement: For high availability, create interface endpoints in multiple Availability Zones
6. On-Premises Connectivity: Interface endpoints can be accessed from on-premises through VPN or Direct Connect - gateway endpoints cannot
7. Endpoint Policies: When questions ask about restricting which resources can be accessed through an endpoint, endpoint policies are the solution
8. Common Scenario: Private EC2 instances needing to access AWS APIs (like Systems Manager) in a private subnet - interface endpoints solve this
9. Troubleshooting: If connectivity issues arise, check security groups, NACLs, and whether private DNS is properly configured
10. Service Support: Know that S3 and DynamoDB support both interface and gateway endpoints, but gateway endpoints are free for these services