PortKnock.ps1

function Invoke-PortKnock
{
    [CmdletBinding()]
    param(
        [Parameter(Mandatory=$true,Position=0)]
        [string] $HostName,
        [Parameter(Mandatory=$true,Position=1)]
        [Int32[]] $Sequence,
        [Parameter(Mandatory=$false,Position=2)]
        [Int32] $Delay = 500
    )

    $Sequence | ForEach-Object {
        $KnockPort = $_
        Write-Host "Knocking on $HostName TCP/$KnockPort"
        $tcpClient = New-Object System.Net.Sockets.TcpClient
        $tcpClient.BeginConnect($Hostname, $KnockPort, $null, $null) | Out-Null
        $tcpClient.Close() | Out-Null
        Start-Sleep -Milliseconds $Delay
    }
}

# Invoke-PortKnock "192.168.25.110" @(10005, 10006, 10007)