What is an Elastic IP Address (EIP) - Elastic IP Address

An Elastic IP Address (EIP) is a public IPv4 address that you can independently purchase and associate with VPC resources—including Elastic Compute Service (ECS) instances, Internet NAT Gateways, Server Load Balancer (SLB) instances, elastic network interfaces (ENIs), and High-availability Virtual IP (HaVip) addresses—for flexible internet access management.

Use cases

Provide internet access for ECS instances

Associate an EIP with an ECS instance or ENI to provide internet access.

Create a unified internet gateway

Associate an EIP with an Internet NAT Gateway or SLB instance to create a unified gateway for internet traffic.

Build a high-availability, public-facing service

Associate an EIP with a High-availability Virtual IP (HaVip) to expose a highly available service to the internet.

Optimize international 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.

Benefits

Flexible management: Associate or disassociate an EIP at any time to handle service changes and failover.
On-demand scaling: Adjust bandwidth caps on demand. Changes take effect immediately.
Cost optimization: EIPs support pay-by-bandwidth and pay-by-data-transfer billing. Add a pay-as-you-go EIP to an Internet Shared Bandwidth instance to reuse bandwidth and reduce costs.
Security and reliability: EIPs include basic DDoS protection by default. For stronger protection, use an Anti-DDoS (Enhanced) EIP.

EIP vs. static public IP

VPC resources use public IPv4 addresses for internet access. These addresses are categorized as static public IPs and EIPs.

A static public IP is assigned only at resource creation (such as ECS or Classic Load Balancer (CLB) instances) and cannot be disassociated or reassigned—it is released when the resource is deleted. An EIP is an independent resource you can dynamically associate or disassociate, providing greater management flexibility. We recommend EIPs.

Public-facing Application Load Balancer (ALB), Network Load Balancer (NLB), and Internet NAT Gateways use EIPs for internet access.

You can convert static public IPs of ECS and CLB instances to EIPs.

EIP selection

Billing method

Billing method	Pay-as-you-go		Subscription
Billing method	Pay-as-you-go (pay-by-data-transfer)	Pay-as-you-go (pay-by-bandwidth)	Subscription (pay-by-bandwidth)
Billable item	Data transfer fee Learn when CDT is used for billing by default. You are charged for the total outbound data transfer from the EIP. Inbound data transfer is free of charge. EIP configuration fee (public IP retention fee) Learn when the EIP configuration fee (public IP retention fee) is waived.	Bandwidth fee EIP configuration fee (public IP retention fee) Learn when the EIP configuration fee (public IP retention fee) is waived.	Bandwidth fee
Billing cycle and bill generation time	The billing cycle is one hour. If you use an EIP for less than one hour, you are billed for a full hour. A bill is typically generated within one hour after the current billing cycle ends. The actual bill generation time may vary.	The billing cycle is one day. Bills are settled on a daily basis. A bill is typically generated in the early morning of the next day. The actual bill generation time may vary.	Billing cycle: The subscription period for your order, which is based on the UTC+8 time zone. The cycle starts at the exact time of activation or renewal and ends at 24:00:00 on the expiration date. A bill is typically generated on the first day of the calendar month after the billing cycle ends. The actual bill generation time may vary.
Scenarios	Workloads with fluctuating traffic peaks, such as gaming or video streaming applications. Temporary or bursty resource usage. Choose the pay-by-data-transfer method if you cannot estimate your data transfer usage.	Workloads with stable traffic peaks. Temporary or bursty resource usage.	Predictable resource usage period. Workloads with stable traffic peaks. Long-term resource usage. This option is more cost-effective than pay-as-you-go (pay-by-bandwidth).
Cost optimization	Upgrade to CDT to get free data transfer quotas and tiered cumulative pricing. Add the EIP to a shared bandwidth. Purchase a Data Transfer Plan to offset data transfer costs.	Add the EIP to a shared bandwidth.	-

Line type

Important

The line type can only be selected when you create an EIP and cannot be changed afterward. Select a line type with caution.

Line type	BGP (Multi-ISP)	BGP (Multi-ISP) Pro	Local ISP
Description	Connects to multiple ISP lines and automatically selects the optimal route to provide a fast and stable connection. This line type is supported in all Alibaba Cloud regions.	Provides an optimized public network route for traffic from outside the Chinese mainland to end users within it (excluding data centers). It uses dedicated ISP lines to reduce latency and improve the quality of international services.	A public IP address directly allocated by a local Internet service provider (ISP) outside the Chinese mainland. Both the autonomous system number (ASN) and the geolocation of the IP address are associated with the local ISP, giving the IP address local network attributes.
Use cases	A general-purpose choice suitable for most internet-facing services, ensuring network stability and coverage.	Optimized for traffic from outside the Chinese mainland to within it, significantly reducing cross-border network latency.	Suitable for workloads that are deployed in regions outside the Chinese mainland and need to access external services over a local network.
Limitations	Services can be deployed in any Alibaba Cloud region. End users can access the services from any region over the internet.	Services can be deployed only in some regions outside the Chinese mainland. The supported regions vary based on the billing method. BGP (Multi-ISP) Pro supported regions pay-as-you-go: China (Hong Kong), Japan (Tokyo), Singapore, Malaysia (Kuala Lumpur), Philippines (Manila), Indonesia (Jakarta), and Thailand (Bangkok). subscription: China (Hong Kong). End users access the services from the Chinese mainland over the internet.	Services can be deployed only in some regions outside the Chinese mainland. Regions that support Local ISP EIPs US (Virginia). This line type is not intended for providing services to the internet, and is not suitable for workloads that have high service availability or protection requirements, such as gaming or finance.

Security protection