An interesting network challenge arises when Amazon EC2 instance in a private VPC subnet need to connect to the Internet. As the subnet is private, the IP addresses assigned to the instances cannot be used in public. Instead, it is necessary to use Network Address Translation ( NAT ) to map the private IP addresses to a public address on the way out, and then map the public IP address to the private address on the return trip. NAT is the virtualization of IP addresses. NAT helps to improve security and decrease the number of IP addresses of organization needs.
NAT gateway on Amazon Web Services ( AWS ) simplifies the task of performing the translation at scale. Instead of configuring, running, monitoring, and scaling a cluster of EC2 instances, we can now create and configure a NAT gateway with a couple of clicks. But we will need at least two instances to ensure high availability.
The NAT gateway has built in redundancy for high availability. Each gateway can handle up to 10 Gbps of bursty TCP, UDP, and ICMP traffic and is managed by AWS. The user needs to control the IP address by assigning an Elastic IP address when user create the gateway.
Similar to all the services, NAT gateway charges in the pay as you go model. The pricing for NAT gateway on AWS starts at $0.045/NAT gateway/hour plus the data processing and data transfer charges. Amazon VPC NAT Gateway is now available in the US East (N. Virginia), US West (Oregon), US West (N. California), EU (Ireland), Asia Pacific (Tokyo), Asia Pacific (Singapore), and Asia Pacific (Sydney) regions.
— Rajesh Bachu (Cloud Engineer), TechMinfy !!