LAN port scan forbidder Chrome Extension

Forbid non-lan web to access LAN.
forbid untrusted web to scan localhost or LAN.

## source code Repo

https://github.com/garywill/LAN-port-scan-forbidder

## What

Webs can try to fetch `127.0.0.1:xxxx` or `192.168.Y.Z:xxxx` to scan your open ports in LAN.

Although browsers have cross-domain protections, webs can't read response contents, **but** can still see the connection succeeds or fails.

There're already reports that some websites using that as tracking fingerprint.

> A web for testing: http://samy.pl/webscan/

## So

Forbid any website behaviors trying to connect to your LAN or localhost, if user is visiting the website via their domains or public ip addresses. (Read the source code `background.js` to see the logic)

> using js library [whitequark/ipaddr.js](https://github.com/whitequark/ipaddr.js) (MIT License) v2.0.0 to judge ip range.

### fallback operation

If user find a web broken, user can temporary set this addon disabled via toolbar button for:

- this one tab

- this one tab and new tabs opened by this tab

- this one window (Firefox only)

- globally

(above can be set as keyboard shortcuts)

there's showy toolbar button badge indicating disabling status.

## cases when web lan scan is properly used

Not all LAN-port-scan are evil.

- Some manufacturers provide web for user's browser to scan lan for their product that need updating.

- Some softwares use `127.0.0.1` communication to interact between native program and web.

How to install LAN port scan forbidder chrome extension in chrome Browser

You can Follow the below Step By Step procedure to install the LAN port scan forbidder Chrome Extension to your Chrome Web browser.

• Step 1: Go to the Chrome webstore https://chrome.google.com/webstore or download the extension LAN port scan forbidder Chrome Extension Download from https://pluginsaddonsextensions.com
• Step 2: Now search for the LAN port scan forbidder in Chrome Webstore Search and click on the search button.
• Step 3: click on the LAN port scan forbidder Chrome Extension Link
• Step 4: in the next page click on the Add to Chrome button to Download and Install the LAN port scan forbidder extension for your Chrome Web browser .