Using the Built-in Subnet Calculator in DDI Central

Overview

DDI Central provides a powerful built-in IPv4 and IPv6 Subnet Calculator to help administrators simplify subnet planning, address allocation, and IP range calculations. This tool allows users to quickly compute subnet ranges, identify usable IPs, and divide networks into smaller subnets based on prefix length.

The Subnet Calculator eliminates manual calculations, ensuring accurate subnet breakdowns, reducing the risk of address conflicts, and optimizing network design for both on-premises and cloud environments.

Accessing the Subnet Calculator

To access and use the subnet calculator in DDI Central, follow these steps:

• Navigate to: DHCP->Network → Subnet → Add Subnet.

• On the Create Subnet Page that appears,click on the black Calculator icon adjacent to the Prefix field. 

  

• The Subnet Calculator window will open, displaying the fields, as shown in the image below.

  

Understanding the Subnet Calculator Fields

1. Subnet Details

This section provides key information about the subnet you are working with:

• Network Address: The base network address of the subnet.
• Prefix: The subnet prefix length (CIDR notation).
• Usable Hosts: The total number of usable host IP addresses in the subnet.
• Range: The entire IP range covered by the subnet.
• First Usable Host: The first available IP address in the subnet.
• Last Usable Host: The last available IP address in the subnet.

2. Dividing the Subnet

Users can choose a specific subnet size to divide the available IP space further.

• Dropdown Selection-> Select a size to divide the subnet address into : Allows users to select a subnet size (e.g., /68, /64, /56 for IPv6).
• Total Number of Subnets: Displays how many smaller subnets will be created based on the selected size.

• Number of /64s: Indicates how many /64 subnets fit into the selected subnet size. This provides real-world examples of the newly created subnets.

  Note: The Number of /64s is displayed in the Subnet Calculator because /64 is the standard subnet size in IPv6 networking. Unlike IPv4, where subnets vary in size, IPv6 generally uses /64 subnets for LANs, ensuring consistent routing and easier network management. When subdividing a larger subnet (e.g., /48 or /56), knowing how many /64 subnets fit within helps administrators properly allocate address space.
   

• Note: First IP usage and Last IP usage fields were added now, where the first 5 and last 5 IPs in the subnet range will be displayed in the examples column. Also, while providing the prefix range in the "prefix range" field, the first IP and last IP in the subnet will be pre loaded in the fields, which can be configured by users.

  

Benefits of Using the Subnet Calculator

• Efficient IP Planning – Quickly calculate subnet ranges and available IPs.
• Minimizes Address Conflicts – Ensures proper IP allocation and avoids overlaps.
• Reduces Manual Errors – Automates complex subnet calculations.
• Optimized for IPv4 & IPv6 – Supports both traditional and next-gen networks.
• On-Prem & Cloud Compatibility – Works across different network infrastructures.

DDI Central’s Subnet Calculator is an essential tool for network administrators, enabling precise address allocation and efficient subnet management. By leveraging this feature, organizations can ensure scalable, conflict-free, and well-structured IP networks.