Explicitly allowed network ports

Computer and userIntune-readyExplicitlyAllowedNetworkPorts

Supported on Microsoft Windows 7 or later

155.0.8059.85

What it does

There is a list of restricted ports built into Google Chrome. Connections to these ports will fail. This setting permits bypassing that list. The value is a comma-separated list of zero or more ports that outgoing connections will be permitted on. Ports are restricted to prevent Google Chrome being used as a vector to exploit various network vulnerabilities. Setting this policy may expose your network to attacks. This policy is intended as a temporary workaround for errors with code "ERR_UNSAFE_PORT" while migrating a service running on a blocked port to a standard port (ie. port 80 or 443). Malicious websites can easily detect that this policy is set, and for what ports, and use that information to target attacks. Each port here is labelled with a date that it can be unblocked until. After that date the port will be restricted regardless of this setting. Leaving the value empty or unset means that all restricted ports will be blocked. If there is a mixture of valid and invalid values, the valid ones will be applied. This policy overrides the "--explicitly-allowed-ports" command-line option. Example value: 10080

What it writes

Hive: HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER
Registry key: Software\Policies\Google\Chrome

Options

Option	Type	Registry value	Allowed values
Explicitly allowed network ports	List of values	`Software\Policies\Google\Chrome\ExplicitlyAllowedNetworkPorts`	Any

Configure and deploy

Choose a state and the option values; the output below is generated from the template for exactly that.

Enabled · Computer · template defaults

Registry file (.reg)

Windows Registry Editor Version 5.00

[-HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\ExplicitlyAllowedNetworkPorts]

PowerShell

$ErrorActionPreference = 'Stop'

function Set-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $PropertyType,
        [Parameter(Mandatory = $true)][object] $Value
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        New-Item -Path $Path -Force | Out-Null
    }

    New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}

function Remove-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (Test-Path -LiteralPath $Path) {
        Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
    }
}

function Clear-RegistryKeyValues {
    param(
        [Parameter(Mandatory = $true)][string] $Path
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return
    }

    foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
        Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
    }
}

# Policy: Explicitly allowed network ports
# Name: ExplicitlyAllowedNetworkPorts
# Scope: Machine
# State: Enabled
# Source: chrome.admx

Clear-RegistryKeyValues -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\ExplicitlyAllowedNetworkPorts'

The OMA-URI is an inferred ADMX-backed Policy CSP candidate derived from the source ADMX file name and policy name.
Some Microsoft policies use built-in Policy CSP pages whose area names don't match the ADMX file name, so verify the candidate against Microsoft Learn before deployment.
The generated payload is incomplete because one or more ADMX element values were not supplied: ExplicitlyAllowedNetworkPortsDesc

ADMX profile candidate (OMA-URI)

./Device/Vendor/MSFT/Policy/Config/ADMX_chrome/ExplicitlyAllowedNetworkPorts

Intune remediation scripts

Detection

$ErrorActionPreference = 'Stop'
$reasons = [System.Collections.Generic.List[string]]::new()

function Test-RegistryValueExists {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return $false
    }

    return $null -ne (Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue)
}

function Test-RegistryValueEquals {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $Kind,
        [Parameter(Mandatory = $true)][object] $Expected
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return $false
    }

    $valueObject = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue
    if ($null -eq $valueObject) {
        return $false
    }

    $actual = $valueObject.$Name
    switch ($Kind) {
        'String' { return [string]$actual -ceq [string]$Expected }
        'ExpandString' { return [string]$actual -ceq [string]$Expected }
        'DWord' { return [uint32]$actual -eq [uint32]$Expected }
        'QWord' { return [uint64]$actual -eq [uint64]$Expected }
        'MultiString' {
            $actualArray = @($actual)
            $expectedArray = @($Expected)
            if ($actualArray.Count -ne $expectedArray.Count) { return $false }
            for ($index = 0; $index -lt $actualArray.Count; $index++) {
                if ([string]$actualArray[$index] -cne [string]$expectedArray[$index]) { return $false }
            }
            return $true
        }
        'Binary' {
            $actualArray = [byte[]]$actual
            $expectedArray = [byte[]]$Expected
            if ($actualArray.Length -ne $expectedArray.Length) { return $false }
            for ($index = 0; $index -lt $actualArray.Length; $index++) {
                if ($actualArray[$index] -ne $expectedArray[$index]) { return $false }
            }
            return $true
        }
        default { return [string]$actual -ceq [string]$Expected }
    }
}

# Policy: Explicitly allowed network ports
# Name: ExplicitlyAllowedNetworkPorts
# Scope: Machine
# State: Enabled
# Source: chrome.admx

$keyPath = 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\ExplicitlyAllowedNetworkPorts'
if (Test-Path -LiteralPath $keyPath) {
    $propertyNames = (Get-Item -LiteralPath $keyPath).Property
    if ($propertyNames.Count -gt 0) {
        $reasons.Add('Key should be empty: HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\ExplicitlyAllowedNetworkPorts') | Out-Null
    }
}

if ($reasons.Count -eq 0) {
    Write-Output 'Compliant'
    exit 0
}

$reasons | ForEach-Object { Write-Output $_ }
exit 1

Remediation

$ErrorActionPreference = 'Stop'

function Set-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $PropertyType,
        [Parameter(Mandatory = $true)][object] $Value
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        New-Item -Path $Path -Force | Out-Null
    }

    New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}

function Remove-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (Test-Path -LiteralPath $Path) {
        Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
    }
}

function Clear-RegistryKeyValues {
    param(
        [Parameter(Mandatory = $true)][string] $Path
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return
    }

    foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
        Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
    }
}

# Policy: Explicitly allowed network ports
# Name: ExplicitlyAllowedNetworkPorts
# Scope: Machine
# State: Enabled
# Source: chrome.admx

Clear-RegistryKeyValues -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\ExplicitlyAllowedNetworkPorts'

History 1 retained release

155.0.8059.8519 Oct 2026
- Already present in the first release ChangeIntel keeps.

Template

Internal name: ExplicitlyAllowedNetworkPorts
Namespace: Google.Policies.Chrome
Template file: chrome.admx
Release: Google Chrome 155.0.8059.85 · file set 1f03ffd12695d620…

Definition, editor controls and support

Definition

<policy class="Both" displayName="$(string.ExplicitlyAllowedNetworkPorts)" explainText="$(string.ExplicitlyAllowedNetworkPorts_Explain)" key="Software\Policies\Google\Chrome" name="ExplicitlyAllowedNetworkPorts" presentation="$(presentation.ExplicitlyAllowedNetworkPorts)" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Google.Policies.Chrome:googlechrome" />
      <supportedOn ref="Google.Policies.Chrome:SUPPORTED_WIN7" />
      <elements>
        <list id="ExplicitlyAllowedNetworkPortsDesc" key="Software\Policies\Google\Chrome\ExplicitlyAllowedNetworkPorts" valuePrefix="" />
      </elements>
    </policy>

Editor controls

<presentation id="ExplicitlyAllowedNetworkPorts" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions"><listBox refId="ExplicitlyAllowedNetworkPortsDesc">Explicitly allowed network ports</listBox></presentation>

Supported platforms and category

Google.Policies.Chrome:category:googlechrome
<category displayName="$(string.googlechrome)" name="googlechrome" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Google.Policies:Cat_Google" />
    </category>
Google.Policies.Chrome:definition:SUPPORTED_WIN7
<definition displayName="$(string.SUPPORTED_WIN7)" name="SUPPORTED_WIN7" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
Google.Policies:category:Cat_Google
<category displayName="$(string.google)" name="Cat_Google" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
Google.Policies.Chrome:category:googlechrome
<category displayName="$(string.googlechrome)" name="googlechrome" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Google.Policies:Cat_Google" />
    </category>
<strings><string id="Google.Policies.Chrome:googlechrome">Google Chrome</string></strings>
Google.Policies.Chrome:definition:SUPPORTED_WIN7
<definition displayName="$(string.SUPPORTED_WIN7)" name="SUPPORTED_WIN7" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="Google.Policies.Chrome:SUPPORTED_WIN7">Microsoft Windows 7 or later</string></strings>
Google.Policies:category:Cat_Google
<category displayName="$(string.google)" name="Cat_Google" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="Google.Policies:google">Google</string></strings>