Help Center/ NAT Gateway/ Service Overview/ Functions
Updated on 2025-11-03 GMT+08:00
View PDF
Share

Functions

Public NAT Gateway

Public NAT gateways provide network address translation (NAT) with 20 Gbit/s of bandwidth for servers in a VPC or for servers in on-premises data centers that connect to a VPC through Direct Connect or VPN.

Public NAT gateways provide source NAT (SNAT) and destination NAT (DNAT).
  • SNAT translates private IP addresses into EIPs, allowing servers within an AZ or across AZs in a VPC to share an EIP to access the Internet.
  • DNAT enables servers within an AZ or across AZs in a VPC to share an EIP to provide services accessible from the Internet. With an EIP, a public NAT gateway forwards the Internet requests from only a specific port over a specific protocol to the specified port of a server, or it can forward all requests to the private IP address of a server regardless of which port they originated on.

Private NAT Gateway

Private NAT gateways provide private address translation (NAT) for cloud servers (ECSs and BMSs) in a VPC. You can configure SNAT and DNAT rules to translate the source and destination IP addresses into transit IP addresses, so that servers in the VPC can communicate with other VPCs or on-premises data centers.

Private NAT gateways provide source NAT (SNAT) and destination NAT (DNAT).
  • SNAT enables servers within an AZ or across AZs in a VPC to share a transit IP address to access servers in remote private networks, like servers in an on-premises data center or a different VPC.
  • DNAT enables servers within an AZ or across AZs in a VPC to share a transit IP address to provide services accessible from servers in remote private networks, like servers in an on-premises data center or a different VPC.