Help Center/ Virtual Private Cloud/ User Guide/ VPC and Subnet/ Subnet/ Modifying a Subnet
Updated on 2025-08-27 GMT+08:00
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Modifying a Subnet

Scenarios

Modify the subnet name, NTP server address, and DNS server address.

Procedure

  1. Go to the subnet list page.
  2. In the subnet list, locate the target subnet and click its name.

    The subnet details page is displayed.

  3. On the Summary tab, click on the right of the parameter to be modified and modify the parameter as prompted.
    Table 1 Parameter descriptions

    Parameter

    Description

    Example Value

    Name
    The subnet name. The name:
    • Can contain 1 to 64 characters.
    • Can contain letters, digits, underscores (_), hyphens (-), and periods (.).

    Subnet

    DNS Server Address
    • Huawei Cloud DNS server addresses are entered by default. The DNS servers can resolve both public and private domain names.

      You can configure private zones to enable ECSs in a VPC to access each other using private domain names. Additionally, you can use the private DNS servers to directly access the private IP addresses of cloud services, such as OBS and SMN. This access offers higher performance and lower latency than Internet-based access.

    • If you want to use other public DNS servers for resolution, you can change the default DNS server addresses. If you use other public DNS servers, private domain name resolution is unavailable.

      You can also click Reset on the right to restore the DNS server addresses to the default value.

      Learn more about how changing VPC subnet DNS server addresses affects ECS configurations and takes effect.

    100.125.x.x

    Domain Name

    Enter domain names separated by spaces, up to 254 characters total. Each label in a domain name can contain a maximum of 63 characters. (For example, test and com are two labels in test.com.)

    To access a domain name, you only need to enter the domain name prefix. ECSs in the subnet automatically match the configured domain name suffix.

    If the domain names are changed, ECSs newly added to this subnet will use the new domain names.

    If an existing ECS in this subnet needs to use the new domain names, restart the ECS or run a command to restart the DHCP Client service or network service.

    NOTE:
    The command for updating the DHCP configuration depends on the ECS OS. The following commands are for your reference.
    • Restart the DHCP Client service: service dhcpd restart
    • Restart the network service: service network restart

    test.com

    DHCP Lease Time

    This parameter is displayed only in regions where IPv4/IPv6 dual stack is not supported.

    The period during which a client can use an IP address automatically assigned by the DHCP server. After the lease time expires, a new IP address will be assigned to the client.
    • Limited: Set the DHCP lease time. The unit can be day or hour.
    • Unlimited: The DHCP lease time does not expire.

    If the time period is changed, the new lease time takes effect when the instance (such as an ECS) in the subnet is renewed next time. You can wait for the instance to be renewed automatically or manually modify the lease time. If you want the new lease time to take effect immediately, manually renew the lease or restart the ECS.

    For details, see How Do I Make the Changed DHCP Lease Time of a Subnet Take Effect Immediately?

    -

    IPv4 DHCP Lease Time

    This parameter is displayed only in regions where IPv4/IPv6 dual stack is supported.

    You can set the DHCP lease time of an IPv4 address.

    The period during which a client can use an IP address automatically assigned by the DHCP server. After the lease time expires, a new IP address will be assigned to the client.
    • Limited: Set the DHCP lease time. The unit can be day or hour.
    • Unlimited: The DHCP lease time does not expire.

    If the time period is changed, the new lease time takes effect when the instance (such as an ECS) in the subnet is renewed next time. You can wait for the instance to be renewed automatically or manually modify the lease time. If you want the new lease time to take effect immediately, manually renew the lease or restart the ECS.

    For details, see How Do I Make the Changed DHCP Lease Time of a Subnet Take Effect Immediately?

    -

    IPv6 DHCP Lease Time

    This parameter is displayed in the region where the IPv4/IPv6 dual stack is supported and when IPv6 is enabled.

    The period during which a client can use an IPv6 address automatically assigned by the DHCP server. You can set the DHCP lease time of an IPv6 address in the same way as how you do with an IPv4 address.

    -

    NTP Server Address

    The IP address of the NTP server. This parameter is optional.

    You can configure the NTP server IP addresses to be added to the subnet as required. The IP addresses are added in addition to the default NTP server addresses. If you do not specify this parameter, no additional NTP server IP addresses will be added.

    A maximum of four unique NTP server IP addresses can be configured. Multiple IP addresses must be separated by a comma (,). If you add or change the NTP server addresses of a subnet, you need to renew the DHCP lease for or restart all the ECSs in the subnet to make the change take effect immediately. If the NTP server addresses have been cleared out, restarting the ECSs will not help. You must renew the DHCP lease for all ECSs to make the change take effect immediately.

    192.168.2.1

    Description

    Supplementary information about the subnet. This parameter is optional.

    The description can contain a maximum of 255 characters and cannot contain angle brackets (< or >).

    -
Parent Topic: Subnet