Tap here to go to the mobile version of the site.
Your Firefox is out of date and may contain a security risk! Upgrade Firefox

Support Forum

If a proxy pac file is used, should any traffic ever bypass the proxy?


Firefox 18.0.2

A proxy has been configured via a pac file.

According to our network traffic, we see a GET request going to a Google based address. The user has confirmed they were using the browser to search via Google for a Microsoft product issue.

Outside of the user disabling the proxy, would there be any reason that web traffic would bypass the proxy and go straight to the web?

We also checked plugins/extensions and nothing appeared to be related to this specific traffic.

Maybe if a request takes too long, the connection defaults to a direct connection to the internet?

Also, almost all of the browser traffic is correctly going through the proxy as expected.

Thanks for any help!

Additional System Details

Installed Plug-ins

  • Google Update
  • Next Generation Java Plug-in 1.6.0_39 for Mozilla browsers
  • Shockwave Flash 11.5 r502
  • Adobe PDF Plug-In For Firefox and Netscape "9.5.3"
  • Citrix Receiver Plugin (Win32)
  • DRM Store Netscape Plugin
  • Npdsplay dll
  • DRM Netscape Network Object
  • The plug-in allows you to open and edit files using Microsoft Office applications
  • Office Authorization plug-in for NPAPI browsers
  • Windows Presentation Foundation (WPF) plug-in for Mozilla browsers


  • User Agent: Mozilla/5.0 (Windows NT 5.1; rv:18.0) Gecko/20100101 Firefox/18.0

More Information

  • Top 10 Contributor
  • Moderator
2046 solutions 8901 answers

Helpful Reply

hello, according to wikipedia: "Should this proxy fail to respond, the browser contacts the website directly, without using a proxy. The latter may fail if firewalls or other intermediary network devices reject requests from sources other than the proxy, a common configuration in corporate networks." http://en.wikipedia.org/wiki/Proxy_auto-config#The_PAC_file

so this may as well have been a temporary issue with the proxy server the traffic is sent through...

Helpful Reply

You sir, are the man... or person. =)

Thank you!