Firefox asks whether a website may reach devices on your local network

A web page may request access to a printer, TV, media server or another service on your local network. Sometimes that is required for casting or configuration; other times the page has no good reason to reach devices behind your router. Firefox can prompt before allowing this class of connection.

Before you start​

Know which website is requesting access and what local device you intended to use. If this is a work or school network, account for its policy and administrator-managed services.

Do it step by step​

1. Pause at the permission prompt and inspect the full site domain in the address bar. A lookalike page should not receive network access.
2. Ask whether the current action genuinely needs a local device. A news article, shopping checkout or random ad normally does not need your printer or NAS.
3. If you need the feature, allow access for the trustworthy site and test the specific device. Avoid Remember or Don't ask again unless repeated use is expected.
4. Review saved permissions in Firefox Settings, Privacy & Security, Permissions or the site's permissions panel. Revoke obsolete grants.
5. If a page behaves suspiciously after access, close it, review the device's logs or account settings where available, and update the device's software through its official interface.

Check the result​

The desired casting or setup task should work when permitted; unrelated sites should have no stored grant. Record which domain actually needs access.

If something goes wrong​

A network permission prompt does not mean that Firefox detected malware. Likewise, allowing a legitimate page does not authenticate every device on the network.

Know the limit​

This browser layer cannot replace a strong router password, device updates or network segmentation. It controls what this web origin may attempt from the browser. Mozilla local-network permission guide