An elastic IP address (EIP) is a public IP address that you can purchase and use as an independent resource. You can associate an EIP with an Elastic Compute Service (ECS) instance, an internal-facing Classic Load Balancer (CLB) instance, an internal-facing Application Load Balancer (ALB) instance, a secondary elastic network interface (ENI), a NAT gateway, or a high-availability virtual IP address (HAVIP). If you want to associate an EIP with an ECS instance, CLB instance, or secondary ENI, make sure that the cloud resource with which you wan to associate the EIP is deployed in a virtual private cloud (VPC).

An EIP is a NAT IP address provisioned in the Internet-facing gateway of Alibaba Cloud and is mapped to the associated cloud resource by using NAT. After an EIP is associated with a cloud resource, the cloud resource can use the EIP to communicate with the Internet.

Features

Feature Description References
Apply for an EIP
  • Apply for a new EIP
  • Restore a released EIP
  • Apply for contiguous EIPs
Apply for an EIP
Create an IP address pool You can enable the system to allocate an IP address from a specific IP address pool to your EIP. You can create an IP address pool and add a range of IP addresses to the IP address pool. When you apply for an EIP, you can specify an IP address pool. This way, the system allocates an IP address from the IP address pool to the EIP. Create and manage IP address pools
Associate an EIP with a cloud resource
  • Associate an EIP with an ECS instance deployed in a VPC
  • Associate an EIP with a CLB instance deployed in a VPC
  • Associate an EIP with a NAT gateway
  • Associate an EIP with an HAVIP
  • Associate an EIP with a secondary ENI
Associate an EIP with an EIP bandwidth plan You can associate an EIP with an EIP bandwidth plan to acquire larger bandwidth. EIP bandwidth plans allow you to manage bandwidth resources in a flexible way. Associate an EIP with an EIP bandwidth plan
Note Application Load Balancer (ALB) instances can use EIPs to provide services over the Internet.
  • When you create an Internet-facing ALB instance, you can enable the system to automatically allocate a public IP address or select an EIP to associate with the ALB instance. For more information, see Create an ALB instance.
  • To switch the network type of an ALB instance from internal-facing to Internet-facing, you must associate an EIP with the ALB instance. For more information, see Change the network type of an ALB instance.

Benefits

EIPs have the following benefits:
  • Allow you to purchase and use as independent resources

    You can purchase and use an EIP as an independent resource. EIPs are not bundled with other computing or storage resources.

  • Allow you to associate with resources anytime

    You can associate an EIP with a cloud resource as needed. You can also disassociate and release an EIP anytime to prevent unexpected charges.

  • Allow you to adjust the maximum bandwidth on demand

    You can modify the maximum bandwidth of an EIP based on your business requirements. The modification immediately takes effect.

  • Flexible billing and low costs

    Multiple billing methods are supported, including subscription, pay-by-bandwidth, and pay-by-data-transfer. You can associate an EIP with an EIP bandwidth plan to reduce bandwidth costs.

Line types

EIPs support BGP (Multi-ISP) lines and BGP (Multi-ISP) Pro lines. The following table describes the differences between BGP (Multi-ISP) and BGP (Multi-ISP) Pro.

Item BGP (Multi-ISP) BGP (Multi-ISP) Pro
Advantages BGP (Multi-ISP) provides high-quality and high-bandwidth BGP lines.
  • Up to 89 high-quality BGP lines are available worldwide.
  • Direct connections can be established in all regions of the Chinese mainland through lines of the following Internet Service Providers (ISPs): China Telecom, China Unicom, China Mobile, China Mobile Tietong, China Netcom, China Education and Research Network (CERNET), National Radio and Television Administration, Dr. Peng Telecom & Media Group, and Founder Broadband Network.
  • You can use BGP (Multi-ISP) with EIP bandwidth plans to obtain bandwidth of 100 Gbit/s and higher.
BGP (Multi-ISP) Pro lines optimize data transmission to the Chinese mainland and improve connection quality for international services. Compared with BGP (Multi-ISP), when BGP (Multi-ISP) Pro lines provide services to users in the Chinese mainland (excluding data centers), cross-border connections are established by using Chinese mainland ISP services. This reduces network latency.
Region All regions China (Hong Kong)

Differences between an EIP and the static public IP address of an ECS instance

The following table describes the differences between an EIP and the static public IP address of an ECS instance.

Item EIP Static public IP address
Supported network VPC VPC and classic network
Used as an independent resource Supported Not supported
Associated with and disassociated from an ECS instance anytime Supported Not supported
Displayed in the ENI information of the associated ECS instance Cut-through mode: Displayed

Classic network: Displayed

VPC: Not displayed

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