Local input processing

Privacy

Cidrspan calculates the numerical block in your browser. Its calculator source does not deliberately send the entered IPv4 address, prefix or calculated result to a server. It does not scan an address, issue DNS requests, read network interfaces or call a remote lookup service. Pasting a real address is not necessary; the fixed example uses a documentation range.

Page-session behavior

Current input and results stay in page memory while you use the calculator. It does not use local storage or session storage to remember an address. The script explicitly restores its fixed public example on startup, including when a browser has initially restored a form value. Reset does the same. Editing the input clears the previous block, bit diagram and export state until you inspect again.

The input has no native form-submission name and the calculator does not build typed values into page URLs. This avoids a calculator-generated query-string copy of the address. Browser extensions, device access, browser-managed restoration and operating-system history are outside this tool's control.

Copies and downloads

Copy uses the browser clipboard interface when available. If permission or that interface is unavailable, the current notes appear in a manual-copy box. Downloads create local text or JSON files through your browser. You control those actions, and they can leave data in your clipboard, downloads folder or device backups. Remove those copies yourself if they contain information you do not want retained.

Hosting and optional contact

No analytics, advertising or consent-platform loader is active in this source release. The hosting provider still receives ordinary requests needed to serve the website, including a requested path, IP address and browser information. A local calculation does not mean that fetching a webpage is anonymous.

The contact email link opens your email application. A message you choose to send is processed by email and forwarding providers and is separate from the local calculation. The published address is a shared forwarding alias; its private destination is not displayed. Avoid emailing passwords, internal network diagrams or confidential infrastructure details. A small invented numerical example usually explains a problem just as well.