An Elastic IP Address (EIP) is a public IPv4 address you can purchase and manage independently. It enables internet access for cloud resources including Elastic Compute Service (ECS) instances in Virtual Private Clouds (VPCs), internet NAT gateways, Server Load Balancer (SLB) instances, secondary elastic network interfaces (ENIs), and high-availability virtual IP addresses (HaVips). You can associate an EIP with or disassociate it from cloud resources at any time, allowing dynamic management of public IP addresses.
Use cases
Enable internet access for ECS instances Associate an EIP with an ECS instance or an ENI to give it internet access.  | Establish a centralized internet gateway Associate an EIP with an internet NAT gateway or an SLB instance to create a centralized ingress and egress for your internet traffic.  |
Deploy a public-facing active-standby service Associate an EIP with an HaVip to deliver a high-availability public-facing service.  | Optimize access for users in the Chinese mainland A BGP (Multi-ISP) Pro EIP uses dedicated carrier lines to reduce latency for users in the Chinese mainland accessing international services.  |
Benefits
Flexible management: Associate an EIP with a cloud resource as needed and disassociate it at any time. This allows you to easily handle business changes and failover scenarios.
On-demand scaling: Adjust the maximum bandwidth at any time to match your business traffic. The change takes effect immediately, so you can promptly handle traffic spikes.
Cost-effective: EIPs support two metering methods: pay-by-bandwidth and pay-by-data-transfer. Associate a pay-as-you-go EIP with an Internet Shared Bandwidth instance to share and reuse bandwidth, reducing your public network costs.
Secure and reliable: EIPs integrate basic DDoS protection by default for basic security. You can use an Anti-DDoS (Enhanced) EIP for even stronger security.
Differences between an EIP and a static public IP address
Resources within a VPC rely on public IP addresses to communicate with the internet over IPv4. Public IPv4 addresses are categorized into two types: static public IP addresses and EIPs.
A static public IP address can only be assigned to a resource, such as an ECS instance or an SLB instance, at creation. It cannot be disassociated or re-associated after creation and is released only when you delete the instance. In contrast, an EIP is an independent public IP resource that you can create, hold, and dynamically manage. We recommend using EIPs for flexible IP management.
Internet-facing Application Load Balancer (ALB) instances, Network Load Balancer (NLB) instances, and internet NAT gateways use associated EIPs to communicate with the internet.
You can convert the static public IP address of an internet-facing ECS or CLB instance into an EIP.
EIP selection guide
Billing method
Billing method | Internet metering method | Use cases |
Pay-by-data-transfer |
If you cannot estimate your traffic usage, use the pay-by-data-transfer method. | |
Pay-by-bandwidth |
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Pay-by-bandwidth |
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Line types
You can select a line type only when you create an EIP. After the EIP is created, the line type can never be changed.
Line type | BGP (Multi-ISP) | BGP (Multi-ISP) Pro |
Description | Delivers a fast and stable user experience by connecting to multiple ISP lines and automatically selecting the optimal route. This line type is supported in all Alibaba Cloud regions. | An optimized public network route for traffic from outside the Chinese mainland to the Chinese mainland. It is designed to improve network performance for end users in the Chinese mainland, excluding data centers. This line type reduces latency and improves the quality of international services through direct connections to dedicated ISP lines. |
Use cases | A general-purpose choice suitable for most internet-facing services, ensuring network stability and broad coverage. | An optimized line for traffic from outside the Chinese mainland to the Chinese mainland, significantly reducing cross-border network latency. |
Limitations |
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Network quality | Standard (traffic passes through regular ISP lines) | High (traffic passes through dedicated ISP lines) |
Cost | Low | Medium |
Security protection
You can select a security protection type only when you create an EIP. After the EIP is created, the security protection type can never be changed.
Security protection type | Default | Anti-DDoS (Enhanced) |
Use cases | For services with no special security requirements. A single EIP provides up to 5 Gbit/s of basic DDoS protection by default, which meets fundamental security needs. | For services requiring terabit-level DDoS protection or when default security is insufficient. |
How to configure | This basic protection is enabled by default for all EIPs. | You must select this type when you create an EIP. |
Limitations | Supported for EIPs in all regions. |
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Billing impact | The default security protection is free of charge. | Incurs security protection fees charged by the Anti-DDoS service. For billing rules, see Anti-DDoS Origin 2.0 (Pay-as-you-go). |
Quick start
Go to the Elastic IP Addresses console, click Create EIP, then create an EIP.
On the Elastic IP Addresses page, find the EIP that you want to manage, and click Associate with Resource in the Actions column. Then, associate the EIP to a cloud resource.