How to disable Internet Explorer Automatic Proxy Configuration

You would think this one would be easy…

Some of our users were noticing that it was taking over 30 seconds to launch IE to a web site that was configured at the command line (i.e. we run “iexplore.exe https://mysite.com”).  While page loading was indeed slow, at least 20 seconds of the delay was seen before IE even stated to load content from the web site in question (determined by using WireShark).  Instead what we saw was a lot of CLDAP chatter and the ever-revealing DNS lookup attempt for hosts starting with the RDN “WPAD”.  Looks like Internet Explorer Web Proxy Auto Detection is wasting our time again.

Traditionally, the solution was to use the “Internet Explorer Maintenance” settings in Group Policy to disable auto proxy config.  However, it appears that with the release of Windows 8, this branch of Group Policy is being deprecated.  So what it the “right” way to set this policy now?  I am using GP Preferences.

Using SysInternals ProcMon, we are able to see that the following registry value is modified when we manually disable automatic proxy detection:
HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections\DefaultConnectionSettings
this is a RegBinary setting, which makes intuitive understanding of the meaning of the value impossible.

Though experimentation, I was able to determine that when the ninth pair of digits is altered from “09″ to “01″, proxy auto configuration is disabled.  The parallel “SavedLegacySettings” value also gets modified, but this value has no effect on actual IE settings.  The fifth pair of settings also gets modified each time you reconfigure the IE connection settings.  I expect these digits represent some sort of change sequence number, as the setting different values here does not seem to affect a behavior change in IE.

So whoopee… another GP Preference setting, and I have saved my colleagues 20 seconds of time on each startup of IE.  If they all use the affected systems once a day for the next 80 days, this whole activity will have been worthwhile.

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