Edge ignores Proxy auto-config (PAC) files

By design Issue #12979608


John I.
Jul 28, 2017
This issue is public.
Found in
  • Microsoft Edge
  • Internet Explorer
Found in build #
Reported by 1 person

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Steps to reproduce

I configure Edge browser to use a proxy setup script but unfortunately the browser ignores the proxy configuration.

The proxy auto-configuration file looks like this:
function FindProxyForURL (url, host)
return "PROXY proxy:443";


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    Comments and activity

    • Microsoft Edge Team

      Changed Assigned To to “Steven K.”

    • Hi John,

      Internet Explorer and Edge on Windows 10-based computers use the WinHttp proxy service to retrieve proxy server information. The 

      WinHttp Proxy service does not support u
      sing the ftp:// or file:// protocol for a PAC file.

      The work around is to server the PAC file from a web server.  See the reference link below.


      Thank you for the support,

      The MS Edge Team

    • Microsoft Edge Team

      Changed Status to “By design”

    • EDGE doesn’t read any PAC file at all.
      I have a PAC file set to an http server and it work fine with IE but when I open EDGE there is nothing, it’s just blank doesn’t show or load anything.

    • Hi Francois,

      Can you please share your pac file and let’s figure out what’s wrong? I had some problem with my pac files too however later I found that it was my pac’s fault, or Edge just doesn’t support the syntax of it. What’s more, you have to set your MIME type for the pac files on the http server. So I rewrote the pac file, configured my server and now it works fine. Running on 16199.19.

    • i have the same problem in w10 1809, IE11 and Edge ingoring PAC file, but FF and Chrome using it, i used http and iis, mime i had set,

      function FindProxyForURL(url, host) {

      // If the requested website is hosted within the internal network, send direct.
      if (isPlainHostName(host) ||
      shExpMatch(host, “*.local”) ||
      isInNet(dnsResolve(host), "", “”) ||
      return "DIRECT";

      // DEFAULT RULE: All other traffic, use below proxies, in fail-over order.
      return "PROXY";


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