Elastic IP

An Elastic IP (EIP) address is a public IP address resource that you can purchase and possess independently.

EIP can be dynamically bound to a VPC ECS instance without restarting the ECS instance. The ECS instance with a bounded EIP can communicate with the Internet.

• You can purchase an EIP as an independent resource rather than bundled with other computing or storage resources.

• You can bind an EIP to an ECS instance in any VPC to allow access via the Internet and release it whenever an Internet communication is not needed.

• You may adjust the bandwidth of an EIP as needed. Bandwidth changes will take effect immediately.

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

Note: Currently, only ECS instances support the binding of an EIP address.

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

EIP supports Pay-As-You-Go billing, which is a post-usage payment method. EIP fees are collected according to the actual network traffic and are billed hourly.

The following table lists the price of EIP addresses in different regions.

Note: The price may have changed, refer to the EIP address console for current prices.

The Alibaba Cloud Management Console provides a simple web-based user interface that allows you to access and configure EIP addresses.

From the console, you can create, modify and manage your EIP addresses.

For a step-by-step guide on how to apply for an Alibaba Cloud EIP address through the Management Console, please read the Quick Start Guide.

To create your own Alibaba Cloud EIP addresses, please read the EIP Documentation for a detailed understanding of how EIP works and how to modify and manage your EIP addresses.

You can use web-based Alibaba Cloud EIP APIs to programmatically create, manage, and achieve greater control of your resources placed within VPC.

The following resources offer detailed information regarding Alibaba Cloud EIP.

Please see the links below for advanced features and Documentation. These resources are useful for developers wishing to integrate Alibaba Cloud EIP with their existing applications or to improve configurations.

• A public IP can be found on the private NIC of the ECS instance, while an EIP is a NAT IP that is mapped to the private NIC of the ECS instance. The EIP, therefore, cannot be found on the NIC of the ECS instance.

• You cannot unbind a public IP from the ECS instance but can bind and unbind an EIP whenever the Internet communication is not needed.

The EIP is configured on the Internet gateway and mapped to the private NIC of the ECS instance, therefore, it cannot be found the private NIC.

A single account can apply for a maximum of 20 EIPs. You may submit a ticket if you wish to apply for more than this number.

Currently, only VPC ECS instances can be added to an EIP.

No, an EIP cannot be added to a Classic ECS instance.

Only one EIP can be added to a single VPC ECS instance.

It may be caused by the following reasons:

• The EIP is not bound to any VPC ECS instances.

• Check if the ECS instance is added to a security group. For example, if the ECS instance is added to the security group that denies access from port number 80, access to EIP from port number 80 will not be accessible.

• Check to see if you have an insufficient account balance.

• An EIP can only be bound to the ECS instance created in a VPC.

• The regions of the EIP and ECS instance are not the same.

• The status of the ECS instance is not running or stopped.

• The ECS instance has been bound to an EIP.

• The ECS instance has a system-allocated public IP.