Register-DNSVMGuest.ps1

function Register-DNSVMGuest
{
    #Requires -modules VMware.VimAutomation.Core,DNSClient
    [CmdletBinding()]
    param (
        # Parameter help description
        [Parameter(Mandatory = $true)]
        [ValidateNotNullorEmpty]
        [String]
        $VIServer,

        # Credential
        [ValidateNotNull()]
        [System.Management.Automation.PSCredential]
        [System.Management.Automation.Credential()]
        $Credential = [System.Management.Automation.PSCredential]::Empty,

        # Parameter help description
        [Parameter()]
        [String[]]
        $ComputerName
        
    )
    
    begin
    {
        function Compare-Things
        {
            [CmdletBinding()]
            [OutputType([bool])]
            Param
            (
                # The singular thing that want to see if it matches
                [Parameter(Mandatory = $true,
                    ValueFromPipelineByPropertyName = $true,
                    Position = 0)]
                [String]
                $ThingA,

                # Any of these things
                [String[]]
                $Things
            )

            Process
            {
                foreach ($thing in $Things)
                {
                    if ($ThingA -like $thing)
                    {
                        return $true

                    }
                }
                return $False
            }
        }
        
        $VISess = Connect-VIServer -Server $VIServer
    }
    
    process
    {
        foreach ($Computer in $ComputerName)
        {
            try
            {
                $VM = Get-VM -Name $Computer -Server $VISess -ErrorAction Stop
                $ip = $($vm.Guest.IPAddress)[0]

                # Might want to see if trusted hosts is going to allow this
                $TrustedHosts = (get-item WSMan:\localhost\Client\TrustedHosts).value -split (',')

                if (Compare-Things -ThingA $ip -Things $TrustedHosts)
                {
                    Try 
                    {
                        $session = New-CimSession -ComputerName $ip -Credential $prodcred -ErrorAction Stop
                        Register-DnsClient -CimSession $session
                        $session | Remove-CimSession
                    }
                    catch
                    {
                        Write-Error "Unable to connect to $Computer via WSMAN"
                    }
                }
                else
                {
                    Write-Error "$ip doesn't match any of the WinRM/WSMAN trusted host filters.  You won't be able to connect"
                }
            }
            catch 
            {
                Write-Error "Unable to find $Computername hosted with $Viserver"
            }
        }
    }
    
    end
    {
        $VISess | Disconnect-VIServer -Force -Confirm:$False -ErrorAction SilentlyContinue
    }
}