Block NetBIOS-based discovery for domain controller location
Verified with Windows 11 25H2 — updated on July 10, 2026
Supported on: At least Microsoft Windows 10 or later
Path in the GPO console
Computer Configuration\Administrative Templates\System\Net Logon\DC Locator DNS Records Description
This policy setting allows you to control whether domain controller (DC) location algorithm uses NetBIOS_based discovery for domain controller location. If you enable or do not configure this policy setting, the DC location algorithm will never use NetBIOS-based discovery. This is the default behavior. If you disable this policy setting, the DC location algorithm may use NetBIOS-based discovery when necessary. The final behavior is further governed by the AvoidFallbackNetbiosDiscovery setting. NetBIOS-based discovery is considered unsecure, has many limitations, and will be deprecated in a future release. For these reasons, NetBIOS-based discovery is not recommended. See https://aka.ms/dclocatornetbiosdeprecation for more information.
Registry
Software\Policies\Microsoft\Netlogon\Parameters Value name: BlockNetbiosDiscovery
Enabled: BlockNetbiosDiscovery = 1
Disabled: BlockNetbiosDiscovery = 0
Export Builder
BETAConfigure the state, scope and options, then generate .reg, PowerShell, Intune and SCCM outputs — or add the setting to a multi-setting collection.
These exports write the registry — this is not a managed GPO. ⓘ
.reg file
Windows Registry Editor Version 5.00
; Exported from gporais.com
; Policy: Block NetBIOS-based discovery for domain controller location
; State: Enabled
; Supported on: At least Microsoft Windows 10 or later
[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Netlogon\Parameters]
"BlockNetbiosDiscovery"=dword:00000001More formats (PowerShell, Intune, SCCM)
PowerShell
# Exported from gporais.com
# Policy: Block NetBIOS-based discovery for domain controller location
# State: Enabled
# Supported on: At least Microsoft Windows 10 or later
$path = 'HKLM:\Software\Policies\Microsoft\Netlogon\Parameters'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'BlockNetbiosDiscovery' -Value 1 -Type DWordIntune XML
No direct Policy CSP / OMA-URI mapping for this policy. Use the Intune Remediation tab, or ingest the ADMX in Intune.Intune Remediation
# === Detection script ===
# Exported from gporais.com
# Policy: Block NetBIOS-based discovery for domain controller location
# State: Enabled
# Supported on: At least Microsoft Windows 10 or later
function Test-RegistryValue {
param(
[Parameter(Mandatory = $true)][string]$Path,
[Parameter(Mandatory = $true)][string]$Name,
[object]$Expected,
[ValidateSet('String', 'DWord', 'MultiString')][string]$Kind = 'String',
[switch]$Absent
)
try {
$item = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction Stop
} catch {
return $Absent.IsPresent
}
if ($Absent.IsPresent) { return $false }
$actual = $item.$Name
if ($Kind -eq 'DWord') { return ([int64]$actual) -eq ([int64]$Expected) }
if ($Kind -eq 'MultiString') {
$actualValues = @($actual)
$expectedValues = @($Expected)
if ($actualValues.Count -ne $expectedValues.Count) { return $false }
for ($i = 0; $i -lt $expectedValues.Count; $i++) {
if ([string]$actualValues[$i] -ne [string]$expectedValues[$i]) { return $false }
}
return $true
}
return [string]$actual -eq [string]$Expected
}
$checks = @(
(Test-RegistryValue -Path 'HKLM:\Software\Policies\Microsoft\Netlogon\Parameters' -Name 'BlockNetbiosDiscovery' -Expected 1 -Kind DWord)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Block NetBIOS-based discovery for domain controller location
# State: Enabled
# Supported on: At least Microsoft Windows 10 or later
$path = 'HKLM:\Software\Policies\Microsoft\Netlogon\Parameters'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'BlockNetbiosDiscovery' -Value 1 -Type DWordSCCM scripts
# Exported from gporais.com
# Policy: Block NetBIOS-based discovery for domain controller location
# State: Enabled
# Supported on: At least Microsoft Windows 10 or later
# SCCM Configuration Item guidance:
# Create a Configuration Item of type "Setting: Script".
# Discovery script: use the Detection script below.
# Remediation script: use the Remediation script below.
# Compliance rule: the Discovery script output equals 'Compliant'.
# === Detection script ===
# Exported from gporais.com
# Policy: Block NetBIOS-based discovery for domain controller location
# State: Enabled
# Supported on: At least Microsoft Windows 10 or later
function Test-RegistryValue {
param(
[Parameter(Mandatory = $true)][string]$Path,
[Parameter(Mandatory = $true)][string]$Name,
[object]$Expected,
[ValidateSet('String', 'DWord', 'MultiString')][string]$Kind = 'String',
[switch]$Absent
)
try {
$item = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction Stop
} catch {
return $Absent.IsPresent
}
if ($Absent.IsPresent) { return $false }
$actual = $item.$Name
if ($Kind -eq 'DWord') { return ([int64]$actual) -eq ([int64]$Expected) }
if ($Kind -eq 'MultiString') {
$actualValues = @($actual)
$expectedValues = @($Expected)
if ($actualValues.Count -ne $expectedValues.Count) { return $false }
for ($i = 0; $i -lt $expectedValues.Count; $i++) {
if ([string]$actualValues[$i] -ne [string]$expectedValues[$i]) { return $false }
}
return $true
}
return [string]$actual -eq [string]$Expected
}
$checks = @(
(Test-RegistryValue -Path 'HKLM:\Software\Policies\Microsoft\Netlogon\Parameters' -Name 'BlockNetbiosDiscovery' -Expected 1 -Kind DWord)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Block NetBIOS-based discovery for domain controller location
# State: Enabled
# Supported on: At least Microsoft Windows 10 or later
$path = 'HKLM:\Software\Policies\Microsoft\Netlogon\Parameters'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'BlockNetbiosDiscovery' -Value 1 -Type DWordBuilding a multi-setting collection? Add this setting and generate combined .reg / PowerShell / GPO scripts.