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Secure Internet and SaaS Access (ZIA)

Identifying the PAC File on a Device Using Browsers

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.

The following sections include information for browser-specific methods. These features belong to the browsers and are not related to Zscaler.

  • If your user is using Google Chrome, do the following:

    The browser version used in this example is Google Chrome 96.0.4664.45.

    1. Enter chrome://net-export/ into the address bar.
    2. In the Options menu, make sure Strip private information is selected, then click Start Logging to Disk.

    1. In the Save As window, click Save to save the log as a JSON file.

    1. Click Stop Logging.

    1. Click Show File.

    1. Open the saved JSON file and search for the keyword proxySettings.

    You see the URL of the PAC file configured to the user's browser, similar to the following example:

    "proxySettings":{"effective":{"pac_url":"http://pac.zscalerbeta.net/zscalerbeta.net/proxy.pac"},
"original":{"pac_url":"http://pac.zscalerbeta.net/zscalerbeta.net/proxy.pac"}}
    Close

  • 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.

    1. In the Internet Options window, click Connections, then LAN Settings.

    1. In the Local Area Network (LAN) Settings window, the URL of the PAC file configured to the user's browser appears in the Address field under Use automatic configuration script.

    Close

  • 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!

    1. In the Search field, enter the word "proxy." The URL of the PAC file configured to the user's browser appears in the value of network.proxy.autoconfig_url.

    Close

  • If your user is using Opera, do the following:

    The browser version used in this example is Opera 36.0.

    1. Click Menu, then click Settings.

    1. Click Browser, then navigate to Network. Click Change Proxy Settings.

    1. In the Internet Properties window, click LAN settings.

    1. In the Local Area Network (LAN) Settings window, the URL of the PAC file configured to the user's browser appears in the Address field under Use automatic configuration script.

    Close

  • If your user is using Safari, do the following:

    The browser version used in this example is Safari 11.0.3 (13604.5.6).

    1. Open Safari, open the Safari menu, then click Preferences....

    The Preferences window appears.

    1. Click Advanced.

    The Advanced tab appears.

    1. Go to Proxies and click Change Settings....

    The Network window appears.

    1. Select Automatic Proxy Configuration and you see any PAC file addresses being used.
    Close

To learn how to configure your browser to use a PAC file, see:

Related Articles
Writing a PAC FileBest Practices for Writing PAC FilesFirewall Requirements for Using PAC FilesUsing Default PAC Files to Forward Traffic to ZIAUsing Custom PAC Files to Forward Traffic to ZIAForwarding Traffic Based on User's Location Using PAC FilesLoad Balancing for PAC Forwarded TrafficDistributing a PAC File URL to UsersConfiguring Internet Explorer to Use a PAC FileConfiguring Google Chrome to Use a PAC FileConfiguring Mozilla Firefox to Use a PAC FileConfiguring Safari to Use a PAC FileIdentifying the PAC File on a Device Using Browsers