Consider the use of NAT gateways for internet access
NAT gateways enable resources within the private subnet to access the internet or other AWS services securely.
When considering NAT gateways, assess the necessity of internet access for your VPC resources carefully. Workloads that can withstand delayed software updates may find the occasional unavailability of a NAT gateway manageable, allowing for cost-effective deployment in a single AZ. Conversely, applications requiring real-time access to external APIs need consistent internet connectivity. To guarantee high availability, deploy a NAT gateway in every AZ that hosts private subnets needing internet access, ensuring seamless operation despite potential AZ disruptions.
While discussing NAT solutions, it is worth mentioning alternatives such as EC2-based NAT instances. Although capable of similar functionality, EC2-based NAT instances are typically not recommended due to their increased complexity, management demands, and the risk of security vulnerabilities if not correctly configured. NAT gateways, being fully managed, offer better scalability, availability, and security features, making them a more suitable choice for most scenarios.
Nonetheless, the use of NAT gateways should not be indiscriminate. If there are significant security considerations or no essential need for internet access, reconsidering the deployment of NAT gateways may be wise. In cases where only specific AWS services need to be accessed, VPC endpoints offer a secure, efficient, and direct connectivity option, eliminating the necessity for broad internet access and embodying a security-first strategy in VPC configuration.
Use VPC endpoints strategically
Incorporating VPC endpoints into your VPC design can significantly enhance the security posture of your AWS environment. By facilitating private connections between your VPCs and AWS services, VPC endpoints help keep your network traffic within the AWS backbone, eliminating the need to expose your VPC resources to the public internet. This minimizes the attack surface and aligns with best practices for securing cloud-based architectures.
However, it is important to select and implement VPC endpoints judiciously:
- Cost considerations: While VPC endpoints offer security benefits, they can introduce significant costs, especially in large-scale AWS deployments. To mitigate these costs without sacrificing security, prioritize gateway endpoints over interface endpoints whenever possible as they are free and provide direct, secure connections to supported AWS services. Additionally, sharing VPC endpoints across your organization can allow you to yield the benefits of using VPC endpoints while significantly reducing overhead. By centralizing VPC endpoints, organizations can realize cost savings and simplify network management across multiple accounts and VPCs.
- Strategic deployment: Determine which AWS services are essential for your VPC’s operations and deploy VPC endpoints specifically for these services. Prioritize services that handle sensitive data or are critical to your application’s functionality. For instance, services such as Amazon S3 for storage, Amazon DynamoDB for database, and AWS Systems Manager for system management are common candidates. This targeted approach ensures you are investing in endpoints that deliver maximum utility and security.
- Policy management: Assign IAM roles to VPC resources requiring endpoint connectivity. Craft VPC endpoint policies that specify which IAM roles have access rights, ensuring that only authorized entities can access them.