How to Test a Proxy PAC File

By Chris Hoffman

Test a Proxy PAC File
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PAC, or proxy auto-configuration, files automatically configure browser proxy settings when the browser's proxy "configuration from a file" setting is enabled and pointed at the specific proxy file. A proxy PAC file contains javascript code. At its simplest, a PAC file gives the Web browser a specific proxy to use for all connections that the proxy administrator for all Web browsers on his network by editing the PAC files being used. More complicated PAC files can specify different proxies for different Web addresses when browsers try to access them. You can test the PAC file on your computer before deploying it on the network server.

Internet Explorer

Open Internet Explorer by clicking "start," "All Programs" and "Internet Explorer."

Click "Tools" and "Internet Options."

Click the "Connections" tab.

Click the "LAN Settings" button.

Uncheck the "Automatically Detect Settings" checkbox by clicking it.

Click "Use Automatic Configuration Script."

Type "file://c:/proxy.pac" into the "Address" box, replacing "c:/proxy.pac" with the full path to the PAC file on your computer.

Click "OK" twice.

Navigate to a website using Internet Explorer to confirm that the PAC file works properly.

Mozilla Firefox

Open Mozilla Firefox by clicking "Start," "All Programs," "Mozilla Firefox" and "Mozilla FIrefox."

Click "Tools" and "Options."

Click the "Advanced" icon at the top of the options window and click the "Network" tab.

Click "Settings" to the right of "Connection."

Click "Automatic Proxy Configuration URL."

Type "file:///c:/proxy.pac" into the box under "Automatic Configuration URL," replacing "c:/proxy.pac" with the full path to the PAC file on your computer.

Click "Reload."

Click "OK" twice."

Navigate to a website with Firefox to confirm that the proxy settings are correct.