Block NTLM Server Exception List
Verified with Windows 11 25H2 — updated on July 10, 2026
Supported on: At least Windows Server 2025, Windows 11
Path in the GPO console
Computer Configuration\Administrative Templates\Network\Lanman Workstation Description
This policy setting determines if NTLM can be used to access specified servers. If you enable this policy setting (valid only if NTLM (LM, NTLM, NTLMv2) is blocked), NTLM can be used to access servers specified. Please enter the desired servers (DNS name, IP address or NetBIOS name) in the edit box, one server name per line. If you disable or do not configure this policy setting, the NTLM access to servers will be determined by other settings.
Registry
HKLM
Software\Policies\Microsoft\Windows\LanmanWorkstation 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 NTLM Server Exception List
; State: Enabled
; Supported on: At least Windows Server 2025, Windows 11
[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\LanmanWorkstation]
"BlockNTLMServerExceptionList"=hex(7):00,00
; REG_MULTI_SZ: one string per input line; edit in regedit if you need richer formatting.More formats (PowerShell, Intune, SCCM)
PowerShell
# Exported from gporais.com
# Policy: Block NTLM Server Exception List
# State: Enabled
# Supported on: At least Windows Server 2025, Windows 11
$path = 'HKLM:\Software\Policies\Microsoft\Windows\LanmanWorkstation'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'BlockNTLMServerExceptionList' -Value @() -Type MultiString
# REG_MULTI_SZ: one string per input line; edit in regedit if you need richer formatting.Intune 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 NTLM Server Exception List
# State: Enabled
# Supported on: At least Windows Server 2025, Windows 11
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
}
$checks = @(
(Test-RegistryValue -Path 'HKLM:\Software\Policies\Microsoft\Windows\LanmanWorkstation' -Name 'BlockNTLMServerExceptionList' -Expected @() -Kind MultiString)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Block NTLM Server Exception List
# State: Enabled
# Supported on: At least Windows Server 2025, Windows 11
$path = 'HKLM:\Software\Policies\Microsoft\Windows\LanmanWorkstation'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'BlockNTLMServerExceptionList' -Value @() -Type MultiString
# REG_MULTI_SZ: one string per input line; edit in regedit if you need richer formatting.SCCM scripts
# Exported from gporais.com
# Policy: Block NTLM Server Exception List
# State: Enabled
# Supported on: At least Windows Server 2025, Windows 11
# 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 NTLM Server Exception List
# State: Enabled
# Supported on: At least Windows Server 2025, Windows 11
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
}
$checks = @(
(Test-RegistryValue -Path 'HKLM:\Software\Policies\Microsoft\Windows\LanmanWorkstation' -Name 'BlockNTLMServerExceptionList' -Expected @() -Kind MultiString)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Block NTLM Server Exception List
# State: Enabled
# Supported on: At least Windows Server 2025, Windows 11
$path = 'HKLM:\Software\Policies\Microsoft\Windows\LanmanWorkstation'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'BlockNTLMServerExceptionList' -Value @() -Type MultiString
# REG_MULTI_SZ: one string per input line; edit in regedit if you need richer formatting.Building a multi-setting collection? Add this setting and generate combined .reg / PowerShell / GPO scripts.