The DHCP options set feature allows you to configure domain names and DNS server IP addresses for Elastic Compute Service (ECS) instances in a virtual private cloud (VPC).
Features and supported regions
Area | Supported region |
Asia Pacific | China (Hangzhou), China (Shanghai), China (Qingdao), China (Beijing), China (Zhangjiakou), China (Hohhot), China (Ulanqab), China (Shenzhen), China (Guangzhou), China (Chengdu), China (Hong Kong), Japan (Tokyo), South Korea (Seoul), Singapore, Malaysia (Kuala Lumpur), Indonesia (Jakarta), Philippines (Manila), and Thailand (Bangkok) |
Europe & Americas | Germany (Frankfurt), UK (London), US (Silicon Valley), and US (Virginia) |
Middle East | UAE (Dubai) and SAU (Riyadh) Important The SAU (Riyadh - Partner Region) region is operated by a partner. |
Features
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.
DHCP option | Description |
Domain name | 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. Important Before you specify custom DNS server IP addresses, take note of the following limits:
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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.
Instance type | Policy |
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:
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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.
Limits
Name/ID | Description | Default value | Adjustable |
N/A | Maximum number of DHCP options sets that can be created by each account | 10 | N/A |
Maximum number of VPCs that can be associated with each DHCP options set | 10 | ||
Maximum number of DHCP options sets that can be associated with each VPC | 1 | ||
Maximum number of domain names that can be specified in each DHCP options set | 1 | ||
Maximum number of DNS server IP addresses that can be specified in each DHCP options set | 4 |
Work with DHCP options sets
For more information, see Work with DHCP options sets.