Enabling Lambda VPC Internet Access

Overview

Domain expertise for enabling internet access from AWS Lambda functions running inside VPC private subnets. Lambda functions in a VPC cannot receive public IP addresses, so outbound internet access requires NAT Gateway infrastructure that routes traffic from private subnets through a public subnet to an Internet Gateway.

Enable internet access for a VPC Lambda function

To set up NAT Gateway infrastructure and configure routing for a Lambda function that needs internet access, follow the procedure exactly. See Lambda VPC internet access setup procedure (opens in a new tab).

Troubleshooting

NAT Gateway not working

Verify the route table associated with the Lambda subnets has a 0.0.0.0/0 route pointing to the NAT Gateway. See the full procedure for details.

Lambda function timeout

Check that security group outbound rules allow the necessary ports and that both the NAT Gateway and Internet Gateway are properly configured.

Network changes not taking effect

VPC networking changes can take 1–2 minutes to propagate. Wait before testing after creating a NAT Gateway or updating route tables.

Route table association issues

Confirm the Lambda function’s subnets are associated with the route table that has the 0.0.0.0/0 route to the NAT Gateway.