What key in windows registry disables IE connection parameter "Automatically Detect Settings"?

I'm trying to set all the connection settings in IE.

I've found how to modify most of them, in the path :

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings

But I can't find the parameter that sets or unsets "Automatically Detect Settings".

Any help ?

I found the solution : it's the 9th byte of this key :

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections] "DefaultConnectionSettings"=hex:3c,00,00,00,1f,00,00,00,05,00,00,00,00,00,00, 00,00,00,00,00,00,00,00,00,01,00,00,00,1f,00,00,00,68,74,74,70,3a,2f,2f,31, 34,34,2e,31,33,31,2e,32,32,32,2e,31,36,37,2f,77,70,61,64,2e,64,61,74,90,0e, 1e,66,d3,88,c5,01,01,00,00,00,8d,a8,4e,9e,00,00,00,00,00,00,00,00

It's a bitfield:

• 0x1: (Always 1)
• 0x2: Proxy enabled
• 0x4: "Use automatic configuration script" checked
• 0x8: "Automatically detect settings" checked

Mask 0x8 to turn it off, i.e., subtract 8 if it's higher than 8.

Thanks to Jamie on google groups.

Update

Based on the VBScript by WhoIsRich combined with details in this answer, here's a PowerShell script to amend these & related settings:

function Set-ProxySettings {
    [CmdletBinding()]
    param ( #could improve with parameter sets 
        [Parameter(Mandatory = $false)]
        [bool]$AutomaticDetect = $true
        ,
        [Parameter(Mandatory = $false)]
        [bool]$UseProxyForLAN = $false
        ,
        [Parameter(Mandatory = $false)]
        [AllowNull()][AllowEmptyString()]
        [string]$ProxyAddress = $null
        ,
        [Parameter(Mandatory = $false)]
        [int]$ProxyPort = 8080 #closest we have to a default port for proxies
        ,
        [AllowNull()][AllowEmptyString()]
        [bool]$UseAutomaticConfigurationScript = $false
    )
    begin {
        [string]$ProxyRegRoot = 'HKCU:\Software\Microsoft\Windows\CurrentVersion\Internet Settings'
        [string]$DefaultConnectionSettingsPath = (Join-Path $ProxyRegRoot 'Connections')
        [byte]$MaskProxyEnabled = 2
        [byte]$MaskUseAutomaticConfigurationScript = 4
        [byte]$MaskAutomaticDetect = 8
        [int]$ProxyConnectionSettingIndex = 8
    }
    process {
    #this setting is affected by multiple options, so fetch once here 
    [byte[]]$DefaultConnectionSettings = Get-ItemProperty -Path $DefaultConnectionSettingsPath -Name 'DefaultConnectionSettings' | Select-Object -ExpandProperty 'DefaultConnectionSettings'

    #region auto detect
    if($AutomaticDetect) { 
        Set-ItemProperty -Path $ProxyRegRoot -Name AutoDetect -Value 1
        $DefaultConnectionSettings[$ProxyConnectionSettingIndex] = $DefaultConnectionSettings[$ProxyConnectionSettingIndex] -bor $MaskAutomaticDetect
    } else {
        Set-ItemProperty -Path $ProxyRegRoot -Name AutoDetect -Value 0
        $DefaultConnectionSettings[$ProxyConnectionSettingIndex] = $DefaultConnectionSettings[$ProxyConnectionSettingIndex] -band (-bnot $MaskAutomaticDetect)
    }
    #endregion

    #region defined proxy
    if($UseProxyForLAN) {
        if(-not ([string]::IsNullOrWhiteSpace($ProxyAddress))) {
            Set-ItemProperty -Path $ProxyRegRoot -Name ProxyServer -Value ("{0}:{1}" -f $ProxyAddress,$ProxyPort)
        }
        Set-ItemProperty -Path $ProxyRegRoot -Name ProxyEnable -Value 1
        $DefaultConnectionSettings[$ProxyConnectionSettingIndex] = $DefaultConnectionSettings[$ProxyConnectionSettingIndex] -bor $MaskProxyEnabled
    } else {
        Set-ItemProperty -Path $ProxyRegRoot -Name ProxyEnable -Value 0        
        $DefaultConnectionSettings[$ProxyConnectionSettingIndex] = $DefaultConnectionSettings[$ProxyConnectionSettingIndex] -band (-bnot $MaskProxyEnabled)
    }
    #endregion

    #region config script
    if($UseAutomaticConfigurationScript){
        $DefaultConnectionSettings[$ProxyConnectionSettingIndex] = $DefaultConnectionSettings[$ProxyConnectionSettingIndex] -bor $MaskUseAutomaticConfigurationScript
    }else{
        $DefaultConnectionSettings[$ProxyConnectionSettingIndex] = $DefaultConnectionSettings[$ProxyConnectionSettingIndex] -band (-bnot $MaskUseAutomaticConfigurationScript) 
    }
    #endregion

    #persist the updates made above
    Set-ItemProperty -Path $DefaultConnectionSettingsPath -Name 'DefaultConnectionSettings' -Value $DefaultConnectionSettings
    }
}

Another way to control this setting is by using an undocumented registry key AutoDetect=0 mentioned on this blog post:

Registry Key : HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\

DWORD AutoDetect = 0 or 1

So the .reg file to turn it off would look like:

Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
"AutoDetect"=dword:00000000

For anyone looking to untick the 'Automatically Detect Settings' box without overwriting the other settings contained in the registry entry, you can use vbscript at logon.

On Error Resume Next

Set oReg   = GetObject("winmgmts:{impersonationLevel=impersonate}!\\.\root\default:StdRegProv")
sKeyPath   = "Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections"
sValueName = "DefaultConnectionSettings"

' Get registry value where each byte is a different setting.
oReg.GetBinaryValue &H80000001, sKeyPath, sValueName, bValue

' Check byte to see if detect is currently on.
If (bValue(8) And 8) = 8 Then

  ' Turn off detect and write back settings value.
  bValue(8) = bValue(8) And Not 8
  oReg.SetBinaryValue &H80000001, sKeyPath, sValueName, bValue

End If

Set oReg = Nothing

I'm aware that this question is a bit old, but I consider that my small update could help other programmers.

I didn't want to modify WhoIsRich's answer because it's really great, but I adapted it to fulfill my needs:

1. If the Automatically Detect Settings is checked then uncheck it.

2. If the Automatically Detect Settings is unchecked then check it.

   On Error Resume Next
   
   Set oReg   = GetObject("winmgmts:{impersonationLevel=impersonate}!\\.\root\default:StdRegProv")
   sKeyPath   = "Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections"
   sValueName = "DefaultConnectionSettings"
   
   ' Get registry value where each byte is a different setting.
   oReg.GetBinaryValue &H80000001, sKeyPath, sValueName, bValue
   
   ' Check byte to see if detect is currently on.
   If (bValue(8) And 8) = 8 Then
       ' To change the value to Off.
       bValue(8) = bValue(8) And Not 8
   ' Check byte to see if detect is currently off.
   ElseIf (bValue(8) And 8) = 0 Then
       ' To change the value to On.
       bValue(8) = bValue(8) Or 8
   End If
   
   'Write back settings value
   oReg.SetBinaryValue &H80000001, sKeyPath, sValueName, bValue
   
   Set oReg = Nothing
   

Finally, you only need to save it in a .VBS file (VBScript) and run it.

If it is simply to disable a group policy that is enforced every 30 minutes you can uncheck the box then change the permissions to Read Only.

I have used a combined answer and made a powershell script which does the trick for you

$name = $PSScriptRoot + "\" + $MyInvocation.MyCommand.Name

if (!([Security.Principal.WindowsPrincipal][Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole] "Administrator")) { Start-Process powershell.exe "-NoProfile -ExecutionPolicy Bypass -File `"$name`"" -Verb RunAs; exit }

$registryPath = "HKCU:\Software\Microsoft\Windows\CurrentVersion\Internet Settings"

$Name = "AutoDetect"

$value = "0"

New-ItemProperty -Path $registryPath -Name $name -Value $value ` -PropertyType DWORD -Force | Out-Null

Read-Host -Prompt "press Enter to Continue"

The script will run as admin and the change the value to 0 ( Disable the Auto-Detect ).

You can always just export the registry, change the setting, then export the registry again and do a diff.

I can confirm this works. I exported the reg file after I had made the adjustments and then put it in a logon script like this:

REM ------ IE Auto Detect Settings FIX ------------------
REG IMPORT \\mydomain.local\netlogon\IE-Autofix.reg 2>NUL

Resurrecting this.

Here's how you can modify registry item binary values concisely in easy-to-follow powershell. In this example DefaultConnectionSettings is the registry item with a REG_BINARY value that we're trying to modify.

$path = "HKCU:\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections"
$objName = "DefaultConnectionSettings"
$getObj = Get-ItemProperty -path $path -name $objName
$getObj.DefaultConnectionSettings[8] = 1
$objValue = $getObj.DefaultConnectionSettings
Set-ItemProperty -path $path -name $objName -Value $objValue

When you use Get-ItemProperty for a registry item with a REG_BINARY value, it gives you a number of child objects in a collection.

By referencing the name of the item (in this case we do getObj.DefaultConnectionSettings) as a child object of getObj, we get an array of values, where each binary value (i.e 50,33,01,00,00,00,00,00,04) has its own position in the array.

Because it is an array we can reference, modify, and iterate through it easily, and we can modify a value by doing $getObj.DefaultConnectionSettings[8] = 1 or whatever number you want in place of 8. The 8 refers to the 9th value in the array. In the example of 50,33,01,00,00,00,00,00,04 the 9th position is 04. Remember that, like other things, arrays start counting at 0.

Setting it = 1 will change that 04 value in the binary to 01 while leaving the rest of the values unchanged in the array.

Finally, we set the change in place with Set-ItemProperty -path $path -name $objName -Value $objValue

Hope this helps others.

Indeed, the 9th byte indicates the check state of the button, but the answers above don't take into account the checkbox which enables manual configuration. This check state value is also present in this ninth byte. The real answer should thus be:

Byte value

00001001 = Manual proxy is checked

00000101 = Use automatic configuration script is checked

00000011 = Automatically detect settings is checked

When multiple checkboxes are checked, the value of the 9th byte is the result of the bitwise OR operation on the values for which the checkbox is checked.

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Internet Explorer\Control Panel]
"Connection Settings"=dword:00000000
"Connwiz Admin Lock"=dword:00000000
"Autoconfig"=dword:00000000
"Proxy"=dword:00000000
"ConnectionsTab"=dword:00000000

I think you can change the "Automatically detect settings" via the registry key name "AutoConfigURL". here is the code that I check in c#. Wish you luck.

    RegistryKey registry = Registry.CurrentUser.OpenSubKey("Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings", true);
                    if(registry.GetValue("AutoConfigURL") != null)
                    {
                        //Proxy Server disabled (Untick Proxy Server)
                        registry.DeleteValue("AutoConfigURL");
                    }