VPC endpoints enable private connectivity between your Virtual Private Cloud (VPC) and supported AWS services, eliminating the need for internet gateways, NAT devices, or VPN connections. This architecture keeps traffic within the AWS network, enhancing security and reducing data transfer costs.
T…VPC endpoints enable private connectivity between your Virtual Private Cloud (VPC) and supported AWS services, eliminating the need for internet gateways, NAT devices, or VPN connections. This architecture keeps traffic within the AWS network, enhancing security and reducing data transfer costs.
There are two types of VPC endpoints:
**Interface Endpoints** use AWS PrivateLink technology, creating elastic network interfaces (ENIs) with private IP addresses in your subnets. These support numerous AWS services including API Gateway, CloudWatch, SNS, SQS, and many others. You can attach security groups to control access and use endpoint policies for fine-grained permissions. Interface endpoints incur hourly charges plus data processing fees.
**Gateway Endpoints** are free and support only Amazon S3 and DynamoDB. They work by adding route table entries that direct traffic to the endpoint. Gateway endpoints are highly available and scale automatically.
**Key architectural considerations:**
1. **Security**: Endpoint policies restrict which principals can access specific resources through the endpoint. Combined with VPC security groups and NACLs, you achieve defense-in-depth.
2. **DNS Resolution**: Enable private DNS to resolve service endpoints to private IP addresses. This allows existing applications to work with minimal changes.
3. **Cross-account access**: VPC endpoints can be shared across accounts using AWS Resource Access Manager, supporting organizational complexity in multi-account architectures.
4. **High availability**: Deploy interface endpoints across multiple Availability Zones for resilience.
5. **Cost optimization**: Gateway endpoints for S3 and DynamoDB are cost-effective compared to NAT gateway data processing charges.
For complex organizations, VPC endpoints integrate with AWS Organizations service control policies (SCPs) to enforce endpoint usage across accounts. They support centralized architectures where shared services VPCs host endpoints accessed by spoke VPCs through Transit Gateway or VPC peering, reducing endpoint proliferation while maintaining private connectivity to AWS services.
VPC Endpoints & Service Integrations
Why VPC Endpoints Matter
VPC endpoints are critical for AWS Solutions Architects because they enable private connectivity between your VPC and supported AWS services or VPC endpoint services. This eliminates the need for internet gateways, NAT devices, VPN connections, or AWS Direct Connect connections to access services. For organizations with strict security and compliance requirements, VPC endpoints provide a secure pathway that keeps traffic within the AWS network.
What Are VPC Endpoints?
VPC endpoints are virtual devices that allow you to privately connect your VPC to supported services. There are three types:
1. Interface Endpoints (AWS PrivateLink) - Creates an elastic network interface (ENI) with a private IP address - Supports most AWS services (S3, DynamoDB, EC2, CloudWatch, KMS, etc.) - Powered by AWS PrivateLink technology - Can be accessed from on-premises via Direct Connect or VPN - Supports endpoint policies for access control - Charges hourly and per GB of data processed
2. Gateway Endpoints - Only supports S3 and DynamoDB - Uses route table entries to direct traffic - No additional charges - Cannot be extended to on-premises networks - Regional scope only
3. Gateway Load Balancer Endpoints - Used for deploying third-party virtual appliances - Enables traffic inspection, firewalls, and intrusion detection
How VPC Endpoints Work
When you create an interface endpoint, AWS provisions ENIs in your specified subnets. DNS entries are created that resolve the service endpoint to these private IPs. When applications make requests to the AWS service, traffic flows through the ENI rather than the public internet.
For gateway endpoints, AWS adds a route to your route table pointing to the endpoint. Traffic destined for S3 or DynamoDB is automatically routed through the gateway endpoint based on prefix lists.
Key Integration Patterns
Cross-Account Access: Interface endpoints can be shared across accounts using AWS Resource Access Manager (RAM). Services can be published via PrivateLink for consumption by other VPCs and accounts.
On-Premises Connectivity: Interface endpoints can be accessed from on-premises through Direct Connect or Site-to-Site VPN. Private DNS must be configured appropriately for resolution.
Multi-Region Considerations: VPC endpoints are regional. For multi-region architectures, endpoints must be created in each region. Use Route 53 Resolver for DNS resolution across regions.
Security Considerations
- Endpoint Policies: JSON policies that control access to the service through the endpoint - Security Groups: Interface endpoints support security groups to control inbound traffic - VPC Policies: Combine with S3 bucket policies and IAM policies for defense in depth
Exam Tips: Answering Questions on VPC Endpoints
Tip 1: When a question mentions keeping traffic private or avoiding the internet, think VPC endpoints first. Look for keywords like 'private connectivity,' 'secure access,' or 'compliance requirements.'
Tip 2: Remember Gateway Endpoints are FREE and only support S3 and DynamoDB. If cost optimization is mentioned alongside S3 or DynamoDB access, gateway endpoints are likely the answer.
Tip 3: For on-premises access to AWS services through private connectivity, Interface Endpoints with PrivateLink is the solution. Gateway endpoints cannot extend to on-premises.
Tip 4: When questions involve third-party security appliances, traffic inspection, or network virtual appliances, consider Gateway Load Balancer Endpoints.
Tip 5: Endpoint policies are separate from IAM policies. Both must allow access for the request to succeed. If a question describes access issues despite correct IAM permissions, check for endpoint policy restrictions.
Tip 6: For scenarios requiring service access from multiple VPCs, consider using AWS PrivateLink with a Network Load Balancer to publish your own services.
Tip 7: Private DNS settings matter for interface endpoints. If applications fail to connect through endpoints, DNS resolution configuration is often the issue.
Tip 8: In questions about organizational complexity with multiple accounts, remember that interface endpoints can be shared via RAM, but each VPC still needs its own endpoint for gateway endpoints.