This topic describes how to create a DHCP options set and specify domain names and DNS server IP addresses.

Background information

By default, the IP addresses of the Alibaba Cloud DNS servers are specified for the ECS instance that you create. The 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.

Virtual Private Cloud (VPC) supports DHCP options sets. You can associate DHCP options sets with VPC networks. After a DHCP options set is associated with a VPC network, existing and new ECS instances in the VPC network all use the configurations of the associated DHCP options set. For more information, see Overview.
Note The DHCP options sets feature is in public preview and is available only in the following regions: China (Chengdu), India (Mumbai), Malaysia (Kuala Lumpur), Indonesia (Jakarta), UAE (Dubai), and UK (London). To use the DHCP options sets feature in the preceding regions,submit a ticket.
DHCP options sets

Procedure

  1. Log on to the VPC console.
  2. In the left-side navigation pane, click DHCP Options Sets.
  3. On the DHCP Options Sets page, click Create DHCP Options Set.
  4. On the Create DHCP Options Set page, set the required parameters for the DHCP options set.
    Parameter Description
    Basic Information
    Instance Name Enter a name for the DHCP options set.

    The name must be 2 to 128 characters in length and can contain letters, Chinese characters, digits, underscores (_), and hyphens (-). It must start with a letter or a Chinese character.

    Description Enter a description for the DHCP options set.

    The description must be 2 to 256 characters in length and cannot start with http:// or https://.

    DHCP Options Sets Configuration
    Domain Name Enter a root domain for ECS instances.

    After you associate the DHCP options set with a VPC network, all ECS instances in the VPC network use the specified root domain.

    Enter example.com in this example.

    DNS Server IP Address Enter DNS server IP addresses.
    The IP addresses of the 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 on Alibaba Cloud. You can customize DNS server IP addresses to meet your requirements. Click Customize DNS server IP addresses to specify the custom DNS server IP addresses. You can specify up to four DNS server IP addresses.
    Notice Before you specify custom DNS server IP addresses, note the following limits:
    • The system automatically specifies the IP addresses of the Alibaba Cloud DNS servers, which are 100.100.2.136 and 100.100.2.138. If you delete these IP addresses, you may not be able to access the basic services on Alibaba Cloud. Proceed with caution.
    • You must add rules to the security group and network ACL (if any) to enable access to the specified custom DNS servers. Otherwise, the services deployed on your ECS instances cannot be resolved. For more information, see Add security group rules and Add network ACL rules.

    In this example, enter 192.168.1.1.

  5. Click OK.