This topic answers common questions about the features and limitations of Elastic IP Addresses (EIPs).
EIP vs. static public IP address
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.
Checking the public IP type
Log on to the ECS console, select the target ECS instance, and click the instance ID to open its details page. The public IP address information is displayed on this page.
The type of IP address is indicated on the page:
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Public IP Address: Indicates that the ECS instance is associated with a static public IP address.
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EIP: Indicates that the ECS instance is associated with an EIP.
EIP quota
By default, you can hold up to 20 EIPs per account. You can request a quota increase.
Are API calls for EIPs rate-limited?
The system throttles API requests if a user makes more than 500 API calls per day.
Using EIPs for DNS resolution
Yes, you can resolve a website domain name to an EIP. You can also use a private IP address for private DNS resolution. For more information, see Add a website resolution.
Editing the EIP description
You can typically edit an EIP's description on its details page. However, this is not possible if the EIP is managed by a third-party service. For example, you cannot edit the description of an EIP that is automatically allocated when you create an internet-facing Network Load Balancer (NLB) instance.
Converting BGP (Multi-ISP) to BGP (Multi-ISP) Pro
No.
You can select an EIP's line type only during creation and cannot change it afterward.
Changing the public IP address
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Public IP type |
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Change an EIP |
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Does an EIP change?
No, an EIP does not change.
An EIP may be released due to instance expiration or overdue account payments. If an EIP is released, you can try to retrieve it by applying for a specific EIP.
A static public IP address is released if the associated ECS instance is released, its public bandwidth is set to 0 Mbps, or the instance is stopped in Economical Mode. When a new static public IP address is assigned to the instance, Alibaba Cloud cannot guarantee that it will be the same as the previous one.
If you need to assign a public IP address to different ECS instances or want to retain a public IP address after an instance is released, we recommend using EIP. Compared to static public IP addresses, EIP are more flexible and can be associated with and disassociated from ECS instances. You can also convert a static public IP address to an EIP.
EIP added to a blacklist
For security reasons, Alibaba Cloud blocks TCP port 25 by default. If you need to send outbound email, we recommend using Alibaba Mail.
If you use an EIP instead of Alibaba Mail for sending emails and your IP address is added to the blacklist of an international anti-spam organization, such as Spamhaus, you must contact the organization to submit an appeal. For example, follow the Spamhaus PBL delisting process to remove your EIP from their blacklist.
Resource group change throttling error
Changing the resource group for many EIPs at once may trigger a throttling error.
This error occurs because the API for adding resources to a resource group has a frequency limit of 60 calls per minute.
To avoid this error, change the resource groups in batches of 60 or fewer per minute.