Privacy policy

Last updated 1 October 2026.

This site is a free lookup tool for MAC addresses and OUI prefixes. It has no accounts, no sign-in, no advertising, and no analytics of its own. The short version is that a lookup you run on this website never leaves your browser.

There is one exception, and it is the MCP endpoint for AI assistants. An MCP lookup is an HTTP request, so the address being looked up does reach the server. That difference is explained in full below, because it is the only part of this site where a lookup leaves your device.

What a lookup on this website does

The page downloads a public dataset from this site and runs the whole search in your browser. The address or prefix you type is matched against that local copy. It is never sent to a server, and this site has no server-side search code at all: the host only serves static files.

The site sets no cookies, runs no advertising or tracking scripts, embeds no third-party content, and sends no telemetry. Three small values are kept in your browser's own local storage so the site remembers them between visits:

  • your light or dark theme choice, under the key mal.theme;
  • your language choice, under the key mal.locale;
  • your recent lookups, so you can revisit them, under the key mal.history.v1.

These stay on your device. They are readable only by this site on this device, are never transmitted, and clearing your browser storage removes them. The recent-lookup list can also be cleared from the interface at any time.

What the host collects

This site is hosted on Cloudflare. Serving any web page means the host sees the request, and a request necessarily carries an IP address and a user-agent string. Cloudflare also collects privacy-first, aggregate web analytics that use no cookies and no client-side state, and that do not fingerprint individuals.

Cloudflare's Web Analytics and Workers Logs processing is governed by Cloudflare's privacy policy, not by this one. This site adds nothing to it.

The MCP endpoint, and why it is different

https://mac.jasontally.com/mcp is an MCP server for AI assistants. It is public, unauthenticated, and read-only. Because a client has to make an HTTP request to use it, an address submitted to that endpoint is visible to the host in the request. Specifically:

  • the MAC address or OUI prefix appears in the body of a POST request to /mcp, so it reaches Cloudflare's network in the same way any website request does;
  • no session is created, no identifier is issued, and no lookup is linked to any other lookup or to any account, because no accounts exist;
  • the server's own code does not write any lookup to storage and emits no log line; the operational request logs kept by the host may still record request metadata such as the timestamp, the IP address, and the user-agent string.

Because these are network requests, treat an MCP lookup the way you would treat typing an address into any website over HTTPS. Do not use the MCP endpoint for anything where that exposure would matter, and note that the browser interface at the home page has no such exposure.

Where the data comes from

The dataset is the public IEEE Registration Authority registries (MA-L, MA-M, MA-S, IAB, and CID), refreshed on each deploy. Historical ownership changes come from runZero mac-tracker, used under the MIT licence. Both are public data about organizations, not about you. This site does not hold registration records of individuals, and a MAC prefix resolves to a registered organization, never to a named person.

What this site never does

  • It does not collect, store, or sell personal information about you.
  • It does not use advertising, ad tracking, or third-party trackers.
  • It does not set cookies.
  • It does not require or offer an account, and it has no user database.
  • It does not log your browser lookups.

Children

The site is a technical reference for network administrators and developers. It is not directed at children, and it knowingly collects no information from anyone, of any age.

Your rights

Because this site collects no personal information and sets no cookies, there is normally nothing for it to export, correct, or delete. If you believe data relating to you has reached the host's operational logs, that processing sits with Cloudflare under its own privacy policy and its own retention commitments; Cloudflare is the right party to contact about it. Requests about this site itself can go through the project's public repository, which is linked from the help page.

Changes to this policy

This policy may change when the site changes, so that it continues to describe the site accurately. The date at the top of this page always reflects the current version.

The terms that govern use of this site are in the terms of service. The lookup methodology and data sources are documented on the help page.