Basic Concepts

EIP

An EIP is a static, public IP address.

An EIP can be directly accessed over the Internet. A private IP address is an IP address on a local area network (LAN) and cannot be routed through the Internet.

You can bind an EIP to an in your subnet to enable the to communicate with the Internet.

Each EIP can be used by only one ECS at a time. If you want ECSs in the same VPC to share an EIP, you have to use a NAT gateway. For more information, see the NAT Gateway User Guide.

SNAT Connections

An SNAT connection consists of a source IP address, source port, destination IP address, destination port, and a transport layer protocol. The source IP address is the EIP, and the source port is the EIP port. An SNAT connection uniquely identifies a session.

DNAT Connections

DNAT connections enable servers in a private network to share an EIP to provide services accessible from the Internet.