How do I use the browser to identify the PAC file on a device?

Zscaler recommends that you install a PAC file for each user to ensure coverage outside the corporate network. When a PAC file is configured on a user's browser, it instructs the browser to forward traffic to a proxy server.

There are methods you can use to identify the PAC file configured on a user's device. For example, you can take traffic captures and check the PAC file requests, or check the registry entry for the PAC file configured.

See below for browser-specific methods. Note that these features belong to the browsers and are not related to Zscaler.

Google Chrome

If your user is using Google Chrome, enter chrome://net-internals/#proxy into the address bar. You will see a page similar to the one below. The browser version used in this example is Google Chrome 49.0.2623.112 m

Google Chrome

Mozilla Firefox

If your user is using Mozilla Firefox, do the following:
The browser version used in this example is Mozilla Firefox 44.0.2.

  1. Enter about:config into the address bar.
  2. Click I'll be careful, I promise!
    See image.
  3. In the Search field, enter the word "proxy". The URL of the PAC file configured to the user's browser will appear in the value of network.proxy.autoconfig_url.
    See image.

Firefox 1

Firefox 1

Firefox 2

Firefox 2

Internet Explorer

If your user is using Internet Explorer, do the following:
The browser version used in this example is Internet Explorer 11.0.9600.17905.

  1. Click the Gear icon to open the Tools menu. Then click Internet options.
    See image.
  2. In the Internet Options window, click Connections, then LAN Settings.
    See image.
  3. In the Local Area Network (LAN) Settings window, the URL of the PAC file configured to the user's browser will appear in the Address field under Use automatic configuration script.
    See image.

IE 1

IE 1

IE 2

IE 2

IE 3

IE 3

Opera

If your user is using Opera, do the following:
The browser version used in this example is Opera 36.0.

  1. Click Menu and then click Settings.
    See image.
  2. Click Browser, then navigate to Network. Click Change Proxy Settings.
    See image.
  3. In the Internet Properties window, click LAN settings.
    See image.
  4. In the Local Area Network (LAN) Settings window, the URL of the PAC file configured to the user's browser will appear in the Address field under Use automatic configuration script.
    See image.

Opera 1

Opera 1

Opera 2

Opera 2

Opera 3

Opera 3

Opera 4

Opera 4