Help Center/ Virtual Private Cloud/ User Guide/ VPC and Subnet/ Subnet/ Viewing the Number of Available IP Addresses in a Subnet
Updated on 2026-06-09 GMT+08:00
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Viewing the Number of Available IP Addresses in a Subnet

Scenarios

After a VPC is created, the number of its available IP addresses is the sum of those in its subnets. After a subnet is created, you can query the number of available IP addresses on the subnet details page. The number of available IP addresses in a subnet helps you allocate IP addresses and prevent service interruptions caused by IP address exhaustion.

Constraints

After a subnet is created, some IP addresses are reserved by the system and cannot be assigned to any instance. For example, in a subnet with CIDR block of 192.168.0.0/24, the following IP addresses are reserved by default:
  • 192.168.0.0: Network ID. This address is the beginning of the private IP address range and will not be assigned to any instance.
  • 192.168.0.1: The gateway address of the subnet.
  • 192.168.0.253: Reserved for the system interface. This IP address is used by the VPC for external communication.
  • 192.168.0.254: DHCP service address.
  • 192.168.0.255: Network broadcast address.

These IP addresses are for reference only. The system assigns reserved IP addresses based on your subnet settings. All other IP addresses in the subnet can be assigned to instances.

Viewing the Number of Available IP Addresses in a Subnet

  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, check the value of Available IP Addresses.
    Figure 1 Viewing the number of available IP addresses

Enabling Subnet IP Address Usage Monitoring

You can also perform the following operations to enable the Monitor Subnet IP Address Usage function for a subnet. After it is enabled, Cloud Eye will monitor the IPv4 address usage of the subnet. For details about subnet monitoring metrics, see Supported Metrics.

  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. In the Basic Information area of the subnet, enable Monitor Subnet IP Address Usage.
    Figure 2 Enabling Monitor Subnet IP Address Usage
  4. After the function is enabled, return to the subnet list, locate the target subnet, and click in the Monitoring column to view the subnet usage metrics.
Parent Topic: Subnet