Only connect if Proxy Server certificate has this principal name
Verified with Microsoft 365/Office 5568.1000 — updated on September 4, 2026
Supported on: At least Windows Server 2008 R2 or Windows 7
Path in the GPO console
User Configuration\Administrative Templates\Microsoft Outlook 2016\Account Settings\Exchange Description
This policy setting specifies the required certificate principal name for the RPC proxy server for Outlook Anywhere. If you enable this policy setting, you must enter a server principal name. You must precede the server name with "msstd:" for this configuration to work. For example, you would enter the following text if the server principal name is mail.fourthcoffee.com: msstd:mail.fourthcoffee.com If you disable or do not configure this setting, Outlook uses the certificate principal name that is specified in Autodiscover.
Registry
HKCU
software\policies\microsoft\office\16.0\outlook\rpc 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: Only connect if Proxy Server certificate has this principal name
; State: Enabled
; Supported on: At least Windows Server 2008 R2 or Windows 7
[HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\outlook\rpc]
"proxyserverprincipalname"=""More formats (PowerShell, Intune, SCCM)
PowerShell
# Exported from gporais.com
# Policy: Only connect if Proxy Server certificate has this principal name
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
# Warning: In SYSTEM context (the Intune default), HKCU targets the SYSTEM profile. Run this script using the logged-on credentials.
$path = 'HKCU:\software\policies\microsoft\office\16.0\outlook\rpc'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'proxyserverprincipalname' -Value '' -Type StringIntune 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: Only connect if Proxy Server certificate has this principal name
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
# Warning: In SYSTEM context (the Intune default), HKCU targets the SYSTEM profile. Run this script using the logged-on credentials.
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
}
$checks = @(
(Test-RegistryValue -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook\rpc' -Name 'proxyserverprincipalname' -Expected '' -Kind String)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Only connect if Proxy Server certificate has this principal name
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
# Warning: In SYSTEM context (the Intune default), HKCU targets the SYSTEM profile. Run this script using the logged-on credentials.
$path = 'HKCU:\software\policies\microsoft\office\16.0\outlook\rpc'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'proxyserverprincipalname' -Value '' -Type StringSCCM scripts
# Exported from gporais.com
# Policy: Only connect if Proxy Server certificate has this principal name
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
# 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: Only connect if Proxy Server certificate has this principal name
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
# Warning: In SYSTEM context (the Intune default), HKCU targets the SYSTEM profile. Run this script using the logged-on credentials.
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
}
$checks = @(
(Test-RegistryValue -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook\rpc' -Name 'proxyserverprincipalname' -Expected '' -Kind String)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Only connect if Proxy Server certificate has this principal name
# State: Enabled
# Supported on: At least Windows Server 2008 R2 or Windows 7
# Warning: In SYSTEM context (the Intune default), HKCU targets the SYSTEM profile. Run this script using the logged-on credentials.
$path = 'HKCU:\software\policies\microsoft\office\16.0\outlook\rpc'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'proxyserverprincipalname' -Value '' -Type StringBuilding a multi-setting collection? Add this setting and generate combined .reg / PowerShell / GPO scripts.