21 Days of AWS using Terraform — Day 13- Introduction to NAT Gateway using Terraform

Welcome to Day 13 of 21 Days of AWS using Terraform. The topic for today is Introduction to Nat Gateway using Terraform

What is NAT Gateway

NAT gateway enables instance in Private Subnet to connect to the internet or other AWS services but prevent the internet from initiating a connection with those instances.

How NAT works

  • NAT device has an Elastic IP address and is connected to the Internet through an internet gateway.
  • When we connect an instance in a private subnet through the NAT device, which routes traffic from the instance to the internet gateway and routes any response to the instance
  • NAT maps multiple private IPv4 addresses to a single public IPv4 address.

NAT gateway doesn’t support IPv6 traffic for that you need to use Egress only gateway.

NOTE: IPv6 traffic is separate from IPv4 traffic, route table must include separate routes for IPv6 traffic.

For more info

https://docs.aws.amazon.com/vpc/latest/userguide/vpc-nat-comparison.html

To create a NAT gateway

Go to VPC Dashboard → NAT Gateways → Create NAT gateways

  • Make sure you select the Public Subnet in your custom VPC
  • For NAT gateway to work, it needs Elastic IP

NOTE: NAT Gateway creation will take 10–15 min

To read the complete blog

GitHub Link