Why Can a Web Page Scan Your Local Network and How to Stop It?

Some malicious download sites execute background scripts that silently scan the ports of your local loopback address `localhost` (127.0.0.1) or your home network range (192.168.x.x), attempting to locate vulnerabilities.

Perimeter Shielding of Local IPs & Localhost

Port scanning inside the browser is conducted via local AJAX requests. AdBlock Network blocks these calls at the source. The extension performs asynchronous read-only requests to multiple independent endpoints to refresh the firewall, using the Address layer to deny outbound requests to private ranges.