NAT Gateway Advantages

A NAT gateway can be deployed across subnets and AZs, so that even if an AZ fails, the public NAT gateway in another AZ can still run normally. The specifications and EIP of a public NAT gateway can be changed at any time.

Multiple NAT gateway specifications are available. Public NAT gateways are stable, reliable and easy to configure and maintain.

Public NAT gateways translate private IP addresses into EIPs and vice versa. This allows servers to share an EIP to access the Internet or provide services accessible from the Internet. You no longer need to configure an EIP for each server, which saves money on EIPs and bandwidths.

Different departments in a large enterprise may have overlapping CIDR blocks, so the enterprise has to replan its network before migrating their workloads to the cloud. The replanning is time-consuming and stressful. The private NAT gateway eliminates the need to replan the network so that customers can retain their original network while migrating to the cloud.

Large enterprises often have overlapping CIDR blocks across departments that cannot communicate with each other once migrated to the cloud. So these enterprises have to replan their network before migrating their workloads to the cloud, which is time-consuming and stressful. To address this issue, they can use a private NAT gateway to map CIDR blocks of departments to different subnets in a VPC for easier management.

Departments of an enterprise may need different levels of security. Private NAT gateways can expose the IP addresses and ports of only specified CIDR blocks to meet high security requirements. An industry regulation agency may require other organizations to use a specified IP address to access their regulation system. Private NAT gateways can help meet this requirement by mapping private IP addresses to that specified IP address.

Isolated services of multiple departments usually use IP addresses from the same private CIDR block. After the enterprise migrates workloads to the cloud, there may be IP address conflicts. Thanks to IP address mapping, the private NAT gateways allow for communication between overlapping CIDR blocks.