Set TLS/SSL security policy for IPP printers: registry value SecurityFlagsBlockUnknownCA and 3 moreComputerHKLM\Software\Policies\Microsoft\Windows NT\Printers\IPP

Policy ID: ConfigureIppTlsCertificatePolicy
Scope: Computer Configuration
Supported on: At least Windows 11 Version 24H2
Source: Administrative Templates (.admx) for Windows 11 2026 Update (26H2) (version 1.0)
Category: Printers

Registry

SecurityFlagsBlockUnknownCA

REG_DWORDComputer

HKLM\Software\Policies\Microsoft\Windows NT\Printers\IPP Current key

Checked: 1
Unchecked: 0
Element: Disallow invalid certificate authority
Value type: REG_DWORD

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT\Printers\IPP]

; Options (use only one)
; Checked
"SecurityFlagsBlockUnknownCA"=dword:00000001
; Unchecked
"SecurityFlagsBlockUnknownCA"=dword:00000000

CMD

:: Options (use only one)

:: Checked
reg add "HKLM\Software\Policies\Microsoft\Windows NT\Printers\IPP" /v "SecurityFlagsBlockUnknownCA" /t REG_DWORD /d 1 /f
:: Unchecked
reg add "HKLM\Software\Policies\Microsoft\Windows NT\Printers\IPP" /v "SecurityFlagsBlockUnknownCA" /t REG_DWORD /d 0 /f

PowerShell

# Common: create the key
New-Item -Path 'HKLM:\Software\Policies\Microsoft\Windows NT\Printers\IPP' -Force | Out-Null

# Options (use only one)
# Checked
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Windows NT\Printers\IPP' -Name 'SecurityFlagsBlockUnknownCA' -PropertyType DWord -Value 1 -Force | Out-Null
# Unchecked
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Windows NT\Printers\IPP' -Name 'SecurityFlagsBlockUnknownCA' -PropertyType DWord -Value 0 -Force | Out-Null

SecurityFlagsBlockCertWrongUsage

REG_DWORDComputer

HKLM\Software\Policies\Microsoft\Windows NT\Printers\IPP Current key

Checked: 1
Unchecked: 0
Element: Disallow non-server certificates
Value type: REG_DWORD

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT\Printers\IPP]

; Options (use only one)
; Checked
"SecurityFlagsBlockCertWrongUsage"=dword:00000001
; Unchecked
"SecurityFlagsBlockCertWrongUsage"=dword:00000000

CMD

:: Options (use only one)

:: Checked
reg add "HKLM\Software\Policies\Microsoft\Windows NT\Printers\IPP" /v "SecurityFlagsBlockCertWrongUsage" /t REG_DWORD /d 1 /f
:: Unchecked
reg add "HKLM\Software\Policies\Microsoft\Windows NT\Printers\IPP" /v "SecurityFlagsBlockCertWrongUsage" /t REG_DWORD /d 0 /f

PowerShell

# Common: create the key
New-Item -Path 'HKLM:\Software\Policies\Microsoft\Windows NT\Printers\IPP' -Force | Out-Null

# Options (use only one)
# Checked
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Windows NT\Printers\IPP' -Name 'SecurityFlagsBlockCertWrongUsage' -PropertyType DWord -Value 1 -Force | Out-Null
# Unchecked
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Windows NT\Printers\IPP' -Name 'SecurityFlagsBlockCertWrongUsage' -PropertyType DWord -Value 0 -Force | Out-Null

SecurityFlagsBlockCertCNInvalid

REG_DWORDComputer

HKLM\Software\Policies\Microsoft\Windows NT\Printers\IPP Current key

Checked: 1
Unchecked: 0
Element: Disallow invalid certificate common name
Value type: REG_DWORD

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT\Printers\IPP]

; Options (use only one)
; Checked
"SecurityFlagsBlockCertCNInvalid"=dword:00000001
; Unchecked
"SecurityFlagsBlockCertCNInvalid"=dword:00000000

CMD

:: Options (use only one)

:: Checked
reg add "HKLM\Software\Policies\Microsoft\Windows NT\Printers\IPP" /v "SecurityFlagsBlockCertCNInvalid" /t REG_DWORD /d 1 /f
:: Unchecked
reg add "HKLM\Software\Policies\Microsoft\Windows NT\Printers\IPP" /v "SecurityFlagsBlockCertCNInvalid" /t REG_DWORD /d 0 /f

PowerShell

# Common: create the key
New-Item -Path 'HKLM:\Software\Policies\Microsoft\Windows NT\Printers\IPP' -Force | Out-Null

# Options (use only one)
# Checked
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Windows NT\Printers\IPP' -Name 'SecurityFlagsBlockCertCNInvalid' -PropertyType DWord -Value 1 -Force | Out-Null
# Unchecked
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Windows NT\Printers\IPP' -Name 'SecurityFlagsBlockCertCNInvalid' -PropertyType DWord -Value 0 -Force | Out-Null

SecurityFlagsBlockCertDateInvalid

REG_DWORDComputer

HKLM\Software\Policies\Microsoft\Windows NT\Printers\IPP Current key

Checked: 1
Unchecked: 0
Element: Disallow invalid certificate date
Value type: REG_DWORD

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT\Printers\IPP]

; Options (use only one)
; Checked
"SecurityFlagsBlockCertDateInvalid"=dword:00000001
; Unchecked
"SecurityFlagsBlockCertDateInvalid"=dword:00000000

CMD

:: Options (use only one)

:: Checked
reg add "HKLM\Software\Policies\Microsoft\Windows NT\Printers\IPP" /v "SecurityFlagsBlockCertDateInvalid" /t REG_DWORD /d 1 /f
:: Unchecked
reg add "HKLM\Software\Policies\Microsoft\Windows NT\Printers\IPP" /v "SecurityFlagsBlockCertDateInvalid" /t REG_DWORD /d 0 /f

PowerShell

# Common: create the key
New-Item -Path 'HKLM:\Software\Policies\Microsoft\Windows NT\Printers\IPP' -Force | Out-Null

# Options (use only one)
# Checked
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Windows NT\Printers\IPP' -Name 'SecurityFlagsBlockCertDateInvalid' -PropertyType DWord -Value 1 -Force | Out-Null
# Unchecked
New-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Windows NT\Printers\IPP' -Name 'SecurityFlagsBlockCertDateInvalid' -PropertyType DWord -Value 0 -Force | Out-Null