NAT Gateways are essential components for enabling instances in private subnets to access the internet securely. However, idle NAT Gateways that aren’t actively processing traffic continue to incur hourly charges, leading to unnecessary AWS costs. CloudFix helps identify and safely eliminate these idle resources to optimize your AWS spending.

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What are NAT Gateways?

NAT (Network Address Translation) Gateways enable instances in private subnets to initiate outbound traffic to the internet while preventing unsolicited inbound connections. They serve as intermediaries between your private networks and the public internet, providing secure, one-way connectivity for resources that need to access external services.

NAT Gateways are commonly used to allow private instances to download updates, connect to external APIs, or access AWS services that don’t have VPC endpoints. They’re a critical component in secure AWS network architectures that follow best practices of isolating resources in private subnets.

The Problem with Idle NAT Gateways

NAT Gateways incur hourly charges regardless of traffic volume. As of this writing, each NAT Gateway costs approximately $0.045 per hour (varies by region), which adds up to around $400 per year per gateway. Many AWS environments accumulate idle NAT Gateways for several reasons:

  • Forgotten testing and development environments
  • Services that have been decommissioned while leaving network infrastructure in place
  • Overprovisioned architecture where each subnet has its own NAT Gateway
  • Temporary NAT Gateways created during migrations that weren’t cleaned up

At scale, these idle NAT Gateways can represent significant wasted spend. A typical enterprise might have dozens of NAT Gateways across multiple regions, potentially wasting thousands of dollars annually on resources that serve no purpose.

How CloudFix Helps

CloudFix automatically identifies NAT Gateways that haven’t processed any data traffic for 30 days or more. These gateways are considered idle and likely candidates for removal. When the fixer is executed, CloudFix:

  1. Identifies NAT Gateways with zero bytes processed over the monitoring period
  2. Safely deletes the idle NAT Gateway
  3. Sends an email notification with the details of the removed gateway, including its subnet, connectivity type, and attached Elastic IP address
  4. Provides all necessary information for manual rollback if needed

This process is non-disruptive and doesn’t require downtime. By automatically removing these idle resources, CloudFix helps you optimize your AWS infrastructure costs without risking service availability.

AWS Services Affected

Amazon EC2
Amazon VPC
Amazon EC2Amazon VPC

Benefits

  • Cost Savings: Eliminates unnecessary spending on idle NAT Gateways, potentially saving up to 19% of your annualized NAT Gateway costs.
  • Reduced Management Overhead: Automatically identifies and removes resources that would otherwise require manual identification and cleanup.
  • Improved Security Posture: Removes unused network components that could potentially increase your attack surface.
  • Easy Rollback: Provides detailed information for recreating the NAT Gateway if needed in the future.
  • Zero Downtime: The entire process is non-disruptive to your workloads.

Identifying Idle NAT Gateways

CloudFix uses AWS CloudWatch metrics to detect NAT Gateways that haven’t processed any data for 30 days or more. Specifically, it monitors the following metrics:

  • BytesInFromDestination: The number of bytes received by the NAT gateway from the destination
  • BytesInFromSource: The number of bytes received by the NAT gateway from clients in your VPC
  • BytesOutToDestination: The number of bytes sent from the NAT gateway to the destination
  • BytesOutToSource: The number of bytes sent by the NAT gateway to clients in your VPC

If all of these metrics show zero bytes over the monitoring period, the NAT Gateway is considered idle. CloudFix then verifies that the NAT Gateway isn’t being used by any active route tables before flagging it for potential removal.

Frequently Asked Questions

Q: Is it safe to delete NAT Gateways that appear idle?

A: Yes, if a NAT Gateway hasn’t processed any traffic for 30 days or more, it’s very likely not being used. CloudFix performs careful verification before recommending removal. Additionally, you can easily recreate the NAT Gateway using the information provided in the email notification if needed.

Q: Can I roll back after CloudFix removes a NAT Gateway?

A: Yes, rollback is possible but requires manual intervention. CloudFix provides all the necessary details in the notification email, including the original subnet, connectivity type (public/private), and any attached Elastic IP address, making it easy to recreate the NAT Gateway if needed.

Q: Will deleting NAT Gateways impact my applications?

A: If the NAT Gateway is truly idle (no traffic for 30+ days), there should be no impact on your applications. However, if you have applications that only occasionally need internet access (less frequently than once a month), you may need to recreate the NAT Gateway when those applications need to connect.

Q: What if we need the NAT Gateway in the future?

A: You can easily recreate the NAT Gateway when needed. CloudFix provides the detailed configuration information to help you recreate it with the exact same settings. This approach gives you the flexibility to provision NAT Gateways only when they’re needed, rather than paying for them continuously.