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IP Address Inventory Planner

Allocate IP addresses from a CIDR range by category, auto-generate hostnames, and export to Excel with PowerShell DHCP reservation commands.

Base Network Configuration
CIDR Network (e.g. 192.168.64.0/21)
Enter a valid CIDR network (e.g. 192.168.64.0/21)
IP Allocation Plan
Base Network
Total IPs
IPs Allocated
IPs Free

About the IP Address Inventory Planner

IP address inventory planning is the process of allocating IP addresses from an allocated CIDR block to different device categories (servers, switches, VoIP phones, etc.) based on requirements. This tool takes a CIDR network range (e.g., 192.168.64.0/21 which contains 2,048 addresses) and lets you define how many IPs each category needs. The planner automatically assigns consecutive IP blocks to each category, auto-generates hostnames, and exports a complete inventory with PowerShell DHCP reservation commands ready to paste into your DHCP server.

Each category is assigned a unique color in the exported Excel file for easy visual tracking. The PowerShell DHCP reservation commands are generated with the correct scope ID, making it simple to automate DHCP lease reservations for critical infrastructure devices. This eliminates manual IP tracking spreadsheets and ensures consistent naming conventions across your network.

Worked Example

Base network: 192.168.64.0/21 (2,048 IPs)
Admin IPs: 30 required → 192.168.64.0 to 192.168.64.29 → ADMIN-001 through ADMIN-030 Servers: 25 required → 192.168.64.30 to 192.168.64.54 → SERVER-001 through SERVER-025 Switches: 20 required → 192.168.64.55 to 192.168.64.74 → SWITCH-001 through SWITCH-020
How are IP addresses assigned to categories?
IPs are assigned in the order you enter categories. The first category gets the first block of IPs, the second category gets the next block, and so on. For example, if Admin needs 30 and Servers needs 25, Admin gets .0 to .29 and Servers gets .30 to .54.
Can I edit the Excel file after export?
Yes, the exported Excel file includes columns for Hostname, Description, Location, and MAC Address that you can edit. The PowerShell commands are pre-filled but can be modified. Re-export after making changes if needed.
How do I use the PowerShell commands?
Copy the PowerShell command from the Excel file and paste it into a PowerShell session on your DHCP server with admin privileges. Each command creates a DHCP reservation for that IP, tying it to a specific MAC address. Replace 00-00-00-00-00-00 with actual MAC addresses before running.

Common Use Cases

  • 🏢
    Network documentation. Create a complete IP address inventory for your site, with all devices pre-allocated and named consistently.
  • ⚙️
    DHCP automation. Generate PowerShell DHCP reservation commands that you can bulk-run on your DHCP server to reserve addresses for critical devices.
  • 📊
    Capacity planning. See at a glance how many IPs you have left in your allocation and plan future network growth.
  • 🔧
    Multi-site inventory. Create separate plans for different office sites or network segments, all within your organisation's IP space.
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    Network engineering training. Understand how CIDR blocks are divided and allocated in real-world scenarios.