A prefix list consists of one or more CIDR blocks. You can use prefix lists to facilitate the configuration and management of virtual private cloud (VPC) route tables and Cloud Enterprise Network (CEN) route tables. You can share prefix lists with other Alibaba Cloud accounts by using the Resource Management service.
Regions that support prefix lists
The following table lists the regions that support IPv4 and IPv6 prefix lists.
Area | Region |
Asia Pacific | China (Hangzhou), China (Shanghai), China (Nanjing - Local Region), China (Qingdao), China (Beijing), China (Zhangjiakou), China (Hohhot), China (Ulanqab), China (Shenzhen), China (Heyuan), China (Guangzhou), China (Chengdu), China (Hong Kong), China (Wuhan - Local Region), China (Fuzhou - Local Region), Japan (Tokyo), South Korea (Seoul), Singapore, Australia (Sydney), Malaysia (Kuala Lumpur), Indonesia (Jakarta), Philippines (Manila), Thailand (Bangkok), and India (Mumbai) |
Europe & Americas | Germany (Frankfurt), UK (London), US (Silicon Valley), and US (Virginia) |
Middle East | UAE (Dubai) and Saudi Arabia (Riyadh) Important The SAU (Riyadh) region is operated by a partner. |
Overview
A prefix list is a set of one or more CIDR blocks that compose a logical object. You can add frequently visited IP addresses to a prefix list and configure routes that point to the prefix list. This way, you do not need to configure routes one by one. If you need to route requests to another CIDR block, you only need to update the prefix list. Route tables that reference the prefix list are automatically updated. You can view, modify, and delete prefix lists created by you.
A prefix list consists of multiple entries. Each entry consists of a CIDR block and a description.
You can use the Resource Sharing service to share a prefix list with another Alibaba Cloud account, or folders or members in a resource directory. If you share a prefix list with an Alibaba Cloud account (principal) within the same resource directory, the invitation is automatically accepted by the principal by default. If the principal does not belong to the same resource directory, the principal must manually accept the invitation.
Billing
The prefix list feature is free of charge.
Scenarios
Associate a custom prefix list with a VPC route table. For more information, see Associate a prefix list with a VPC route table.
Associate a prefix list with a CEN route table. For more information, see Associate a prefix list with a CEN route table.
Share a prefix list. For more information, see Share a prefix list.
Limits and quotas
Limits
A prefix list can be used only in the region where the prefix is created.
Prefix lists support IPv4 and IPv6.
When you create a prefix list, you must specify the maximum number of entries. After you associate a prefix list with a route table, the prefix list consumes the quota of routes in the route table. For example, a VPC route table supports up to 200 custom routes. After you associate a prefix list that consists of 20 entries with the VPC route table, the VPC route table supports up to 180 custom routes.
You cannot associate a prefix list with a gateway route table.
When you create gateway endpoints for different cloud service types in a region for the first time, the system automatically creates a system prefix list. The system prefix list cannot be modified or deleted. For more information, see Gateway endpoints.
Quotas
Name | Description | Default value | Adjustable |
vpc_quota_prefixlist_num | Maximum number of prefix lists that can be created by an Alibaba Cloud account | 10 | You can request a quota increase by using one of the following methods:
|
vpc_quota_prefixlist_cidr_num_per_prefixlist | Maximum number of entries supported by each prefix list | 50 | |
vpc_quota_prefixlist_accept_shared_prefixlist_num | Maximum number of prefix lists that can be shared with each principal | 10 | |
vpc_quota_prefixlist_share_user_num_per_prefixlist | Maximum number of principals with which each prefix list can be shared | 10 | |
N/A | Maximum number of times that each prefix list can be associated | Unlimited | No |
For more information about resource sharing quotas, see Limits on resource sharing.
References
For more information about how to create, manage, and use prefix lists, see the following topics: