使用 Powershell 和 Try/Catch 更新特定注册表项？

Question

我需要一些帮助来将下面的粗略脚本修改为：

更改前检查注册表值是否存在。
更新特定的注册表项。
只重启 DNS 服务。
使用内置 Powershell 测试 DNS 功能，然后在一切正常且没有错误时退出脚本。

Import-Module DnsServer

try
{
    $RegistryPath = 'HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNS\Parameters'
    $ipV4 = Test-Connection -ComputerName $env:COMPUTERNAME -Count 1 | Select IPV4Address

    #Test & check the DNS value if it is changed already or not?
    If ( (Get-ItemProperty -Path $RegistryPath -Name 'TcpReceivePacketSize').ToString() -ne 0xFF00 )
    {
        # Update the below Registry key value:
        Subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNS\Parameters
        Value: TcpReceivePacketSize
        Type: DWORD
        Value data: 0xFF00
        
        # Restart the DNS service after the succesful change
        net stop dns
        net start dns
        
        Get-ItemProperty -Path $RegistryPath | Format-List
        
        #Test the DNS server functionality, if no errors, generated from the below test, then all is good, exit script.
        try
        {
            $testConnection = Test-Connection $domaincontroller -Count 1
            If (($testConnection -ne "") -or ($testconnection -ne $null))
            {
                Test-DnsServer -IPAddress $ipV4
                Test-DnsServer -IPAddress $ipV4 -Context Forwarder
                Test-DnsServer -IPAddress $ipV4 -Context RootHints
                Test-DnsServer -IPAddress $ipV4 -ZoneName $env:USERDOMAIN
            }
            else
            {
                Write-Host "$computername DNS test failed".
                Exit
            }
        }
        catch
        {
            Write-Output "Exception Type: $($_.Exception.GetType().FullName)"
            Write-Output "Exception Message: $($_.Exception.Message)"
        }

    }
    else
    {
        Write-Host "$computername DNS has been updated" 
    }
}
catch
{
    Write-Output "Exception Type: $($_.Exception.GetType().FullName)"
    Write-Output "Exception Message: $($_.Exception.Message)"
}

上面的脚本导致以下错误：

Exception Type: System.Management.Automation.PSArgumentException
Exception Message: Property TcpReceivePacketSize does not exist at path HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNS\Parameters.

这是根据这篇文章：https://support.microsoft.com/en-us/help/4569509/windows-dns-server-remote-code-execution-vulnerability

Answer 1

要使用 PowerShell cmdlet 获取或设置注册表项，您需要使用 PowerShell 驱动器名称 HKLM:

HKLM:\SYSTEM\CurrentControlSet\Services\DNS\Parameters

或在长配置单元名称前添加提供者 Registry::（双冒号）：

Registry::HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNS\Parameters

^见Note

$RegistryPath = 'HKLM:\SYSTEM\CurrentControlSet\Services\DNS\Parameters'

# try and get the property 'TcpReceivePacketSize'
$property = Get-ItemProperty -Path $RegistryPath -Name 'TcpReceivePacketSize' -ErrorAction SilentlyContinue
if (!$property) {
    Write-Host "Creating new property 'TcpReceivePacketSize'"
    # create the registry path if not already exists
    if (!(Test-Path -Path $RegistryPath)) {
        $null = New-Item -Path $RegistryPath -Force
    }
    # set the property TcpReceivePacketSize to the wanted value
    $null = New-ItemProperty -Path $RegistryPath -Name 'TcpReceivePacketSize' -Value 0xFF00 -Type DWORD
}
elseif ([int]$property.TcpReceivePacketSize -ne 0xFF00) {
    # the property was found, but the value needs to be set to 0xFF00
    Write-Host "Updating property 'TcpReceivePacketSize'"
    Set-ItemProperty -Path $RegistryPath -Name 'TcpReceivePacketSize' -Value 0xFF00 -Type DWORD
}


# do the rest of your Dns testing here

使用 Powershell 和 Try/Catch 更新特定注册表项？

Updating specific registry entry using Powershell and Try/Catch?

powershell

dns

powershell-remoting

powershell-7.0