What is an EIP address?

Last Updated: Feb 11, 2018

An Elastic IP (EIP) address is a public IP address resource that you can purchase and possess independently. You can bind an EIP address to an ECS instance of the VPC network, a private SLB instance of the VPC network, or a NAT gateway.

An EIP address is a type of NAT IP address. It is located in a public network gateway of Alibaba Cloud, and is mapped to the private network interface card (NIC) of the bound ECS instance in the way of NAT. Therefore, the ECS instance bound with the EIP address can communicate with the Internet without disclosing the EIP address on the NIC.

EIP address features

  • Independently purchased and possessed

    • You can purchase an EIP address as an independent resource instead of purchasing it together with other computing or storage resources.
  • Flexible binding

    • You can bind an EIP address to an ECS instance in any VPC as needed to make the instance accessible to the Internet, and release it whenever the Internet communication is not needed.
  • Configurable network capabilities

    • You can adjust the bandwidth of an EIP address as needed. The bandwidth change takes effect immediately.

Differences between an EIP address and an ECS public IP address

The following table lists the differences between an EIP address and an ECS public IP address.

Item EIP address ECS public IP address
Network environments supported VPC VPC and Classic Network
Independently possessed Yes No
Elastically bound to and unbound from an ECS instance Yes No
Disclosed on the NIC of the ECS instance No Classic Network: Yes
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