What Is NAT Gateway?¶
Public NAT gateways are used to provide NAT.
Public NAT Gateways¶
A public NAT gateway enables cloud and on-premises servers in a private subnet to access the Internet or provide services accessible from the Internet. Cloud servers are ECSs in a VPC. On-premises servers are servers in on-premises data centers that connect to a VPC through Direct Connect or Virtual Private Network (VPN). A public NAT gateway supports up to 20 Gbit/s of bandwidth.
Public NAT gateways offer source NAT (SNAT) and destination NAT (DNAT).
SNAT translates private IP addresses into elastic IP addresses (EIPs), allowing traffic from a private network to go out to the Internet.
Figure 1 shows how an SNAT rule works.
Figure 1 NAT gateway with an SNAT rule¶
DNAT enables multiple servers within an AZ or across multiple AZs in a VPC to share EIPs to provide services accessible from the Internet. With an EIP, a NAT gateway forwards the Internet requests from only a specific port and over a specific protocol to a specific port of a server, or it can forward all requests to the server regardless of which port they originated on.
Figure 2 shows how a DNAT rule works.
Figure 2 NAT gateway with a DNAT rule¶
How Do I Access the NAT Gateway Service?¶
You can access the NAT Gateway service through the management console or using HTTPS-based APIs.
Management console
Log in to the management console and choose NAT Gateway from the service list to perform operations on the NAT gateway.
APIs
Use APIs if you need to integrate NAT Gateway into your own system solution. For details, see the NAT Gateway API Reference.