Hashito System Home 日本語 Tools Blog Posters
Loading
100%
Parent networks above, child networks below
How to use: press Add segment to create a block, then select it and set its name, network IP, subnet mask and parent network under Segment settings on the right. Apply changes redraws the diagram and marks in red anything that falls outside its parent network or overlaps a segment at the same level. IP calculation shows the network address, mask, first and last usable IP, broadcast address, and the ranges not yet allocated to child networks. Drag to move the diagram, use the wheel to zoom, press Fit to view to see everything, and Arrange to re-order the blocks by level. On narrow screens, the List and Details buttons at the top open the side panels. Use Export Markdown to write the design out as Markdown. All calculation happens in your browser, and nothing you enter is sent anywhere.
To work out a single CIDR, try the Subnet Calculator, and for IPv6 addresses see the IPv6 Address Expander and Compressor. Our free learning posters illustrate how networks and the web fit together.
Related tools: Subnet Calculator Browser Info Viewer URL Parser HTTP Status Codes

Frequently Asked Questions

What is a parent network, and how are parent-child relationships decided?

Each segment can have exactly one parent: the larger address space that contains it. Choosing a parent network in the settings on the right creates the relationship, and the diagram places the parent above the child and joins them with a line. A segment itself and everything below it are left out of the list of candidates, so a circular relationship cannot be created.

How are overlaps and out-of-range segments detected?

The network address and the broadcast address are derived from the IP and the subnet mask you enter. The tool then checks whether the segment fits inside its parent network, and whether its address range overlaps any sibling that shares the same parent. It also checks that the IP you entered sits on a network boundary and that the gateway falls inside the segment. Any segment with a problem is marked in red and the reason is written out in words.

Is my design sent to a server, or stored anywhere?

No. Calculation, drawing, and Markdown generation all happen in JavaScript inside your browser, and what you enter is never sent to or stored on a server. Because of that, reloading the page returns everything to its initial state. To keep a design, use Export Markdown and download it as a Markdown file.

How many segments can I add?

Up to 300. The overlap check compares every pair of segments, so the work grows with the square of the count, and without a limit the tool would stop responding. Once the limit is reached nothing is added and a message is shown instead. For a very large design, split the work into separate files per site or per environment.