The DHCP options set feature allows you to configure domain names and DNS server IP addresses for ECS instances in a VPC.
Regions that support peering connections
The following table describes the regions that support DHCP options sets.
China (Qingdao), China (Beijing), China (Zhangjiakou), China (Hohhot), China (Ulanqab), China (Hangzhou), China (Shanghai), China (Shenzhen), China (Guangzhou), China (Chengdu), China (Hong Kong), 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)
UAE (Dubai) and SAU (Riyadh - Partner Region)
DHCP is an Internet protocol that automatically provides an TCP/IP host with its IP address and other related configuration information. By default, the IP addresses of Alibaba Cloud DNS servers are specified for the ECS instance that you create. Alibaba Cloud DNS servers cannot resolve private domain names. You can specify custom DNS server IP addresses for your ECS instance. However, the custom configurations are cleared after you restart the ECS instance.
VPCs support DHCP options sets. You can specify domain names and DNS server IP addresses for a DHCP options set. Then, you can associate the DHCP options set with one or more VPCs that belong to the same region. Then, newly created ECS instances in the VPCs use the configurations of the DHCP options set. After the DHCP options set is synchronized to existing ECS instances, existing ECS instances also use the configurations of the DHCP options set. For more information, see How DHCP options sets apply to ECS instances.
The following table describes the domain names and DNS server IP addresses in DHCP options sets.
The root domain of the ECS instance, for example, example.com.
DNS server IP address
The IP addresses of the DNS servers.
The IP addresses of Alibaba Cloud DNS servers, which are 100.100.2.136 and 100.100.2.138, are used by default. This ensures that you can access basic services deployed on Alibaba Cloud. You can also specify at most four custom DNS server IP addresses to meet your business requirements.
Before you specify custom DNS server IP addresses, take note of the following limits:
How DHCP options sets are applied to ECS instances
The following table describes how a DHCP options set is applied to new and existing ECS instances deployed in a VPC after the DHCP options set is associated with the VPC.
Existing ECS instances (ECS instances that are created in the VPC before the DHCP options set is associated with the VPC).
If one of the following operations is performed, the DHCP options are synchronized to the existing ECS instances in the VPC:
New ECS instances (ECS instances that are created in the VPC after the DHCP options set is associated with the VPC).
No operation is required. The DHCP options are automatically synchronized to the newly created ECS instances in the VPC.
DHCP options sets are also applicable to ECS instances that are created in a VPC for which VPC sharing is enabled. For more information, see Overview of VPC sharing.
Maximum number of DHCP options sets that can be created with each Alibaba Cloud account
Maximum number of VPCs that can be associated with each DHCP options set
Maximum number of DHCP options sets that can be associated with each VPC
Maximum number of domain names that can be specified in each DHCP options set
Maximum number of DNS server IP addresses that can be specified in each DHCP options set
VPCs that cannot be associated with DHCP options sets
If a VPC contains an ECS instance that belongs to one of the following instance families, the VPC does not support DHCP options sets:
ecs.c1, ecs.c2, ecs.c4, ecs.ce4, ecs.cm4, ecs.d1, ecs.e3, ecs.e4, ecs.ga1, ecs.gn4, ecs.gn5, ecs.i1, ecs.m1, ecs.m2, ecs.mn4, ecs.n1, ecs.n2, ecs.n4, ecs.s1, ecs.s2, ecs.s3, ecs.se1, ecs.sn1, ecs.sn2, ecs.t1, and ecs.xn4.
For more information, see Advanced VPC features.
Work with DHCP options sets
For more information, see Work with DHCP options sets.