Get-PortStats.ps1

# https://www.reddit.com/r/PowerShell/comments/4emc45/changing_output_of_script_to_csv/

function Get-PortStats {
    param (
        [string[]]$Computers = $env:computername,
        [string]$User,
        [string]$Password,
        [int]$CollectionInterval,
        [string]$OutputFilePath,
        [string]$PsExecLocation
    )

    begin {
        function ProcessArguments ($paComputers, $paUser, $paPassword) {
            #// Processes the arguments passed into the script such as getting the appropriate credentials if specified.
            $paComputers = $paComputers.Split(';')
            if ($paComputers -isnot [System.String[]]) {
                $paComputers = @($paComputers)
            }

            #// If credentials are passed into this script, then make them secure.
            if ($paUser -ne '') {
                if ($paPassword -ne '') {
                    $paPassword = ConvertTo-SecureString -AsPlainText -Force -String $paPassword
                    $paCredential = New-Object System.Management.Automation.PsCredential -ArgumentList $paUser, $paPassword
                } else {
                    $paCredential = Get-Credential -Credential $paUser
                }
            }

            [pscustomobject]@{
                Computers = $paComputers
                Credential = $paCredential
            }
        }

        function Invoke-PsExec ($peComputer, $peCommand, $peUser, $pePassword, $peCredential) {
            #// Executes PsExec to get data from remote computers.
            if ($PsExecLocation) {
                $PsExec = $PsExecLocation
            } else {
                $PsExec = '.\psexec.exe'
            }

            if ($peUser -ne '') {
                if ($pePassword -eq '') {
                    $pePassword = $peCredential.GetNetworkCredential().Password
                }
                $sPsCmd = "$PsExec \\$peComputer /AcceptEula -u $peUser -p `"$pePassword`" -s $peCommand 2> `$null"
                Write-Warning 'Credentials sent in clear text to the remote computer using PsExec! Prevent this by not providing credentials to this script and logging in with a domain account with admin privileges to the remote computer or by using network encryption such as IPSec.'
            } else {
                $sPsCmd = "$PsExec \\$peComputer /AcceptEula $peCommand"
            }

            Invoke-Expression -Command $sPsCmd
        }

        function Get-TcpDynamicPortRange ($tdprComputer, $tdprUser, $tdprPassword, $tdprCredential) {
            $sCmd = 'netsh int ipv4 show dynamicportrange tcp'

            if ($tdprComputer -eq $env:COMPUTERNAME) { # local
                $oOutput = Invoke-Expression -Command $sCmd
            } else { # not local
                #// Use PsExec
                $oOutput = Invoke-PsExec -peComputer $tdprComputer -peCommand $sCmd -peUser $tdprUser -pePassword $tdprPassword -peCredential $tdprCredential
            }

            $oDynamicPortRange = [pscustomobject]@{
                StartPort = 0
                EndPort = 0
                NumberOfPorts = 0
            }

            foreach ($sLine in $oOutput) {
                if ($sLine.IndexOf('Start Port') -ge 0) {
                    $aLine = $sLine.Split(':')
                    [int]$oDynamicPortRange.StartPort = $aLine[1]
                }

                if ($sLine.IndexOf('Number of Ports') -ge 0) {
                    $aLine = $sLine.Split(':')
                    [int]$oDynamicPortRange.NumberOfPorts = $aLine[1]
                }
            }

            $oDynamicPortRange.EndPort = $oDynamicPortRange.StartPort + $oDynamicPortRange.NumberOfPorts - 1

            $oDynamicPortRange
        }

        function Get-ActiveTcpConnections ($atcComputer, $atcUser, $atcPassword, $atcCredential) {
            $sCmd = 'netstat -ano -p tcp'

            if ($Computer -eq $env:COMPUTERNAME) { # local
                $oOutput = Invoke-Expression -Command $sCmd
            } else { # not local
                #// Use PsExec
                $oOutput = Invoke-PsExec -peComputer $atcComputer -peCommand $sCmd -peUser $atcUser -pePassword $atcPassword -peCredential $atcCredential
            }

            if ($oOutput -ne $null) {
                $u = $oOutput.GetUpperBound(0)
                $oOutput = $oOutput[4..$u]
                foreach ($sLine in $oOutput) {
                    $iPropertyIndex = 0
                    $aLine = @($sLine.Split(' ')).where{$_ -notmatch '^\s*$'}
                    $oActiveConnection = @{}
                    for ($c = 0; $c -lt $aLine.Count;$c++) {
                        if ($aLine[$c] -ne '') {
                            switch ($iPropertyIndex) {
                                0 {
                                    $oActiveConnection.Add('Proto', $aLine[$c])
                                }
                                1 {
                                    $aIpPort = $aLine[$c].Split(':')
                                    $oActiveConnection.Add('LocalAddress', $aIpPort[0])
                                    $oActiveConnection.Add('LocalPort', [int]$aIpPort[1])
                                }
                                2 {
                                    $aIpPort = $aLine[$c].Split(':')
                                    $oActiveConnection.Add('ForeignAddress', $aIpPort[0])
                                    $oActiveConnection.Add('ForeignPort', [int]$aIpPort[1])
                                }
                                3 {
                                    $oActiveConnection.Add('State', $aLine[$c])
                                }
                                4 {
                                    $oActiveConnection.Add('PID', [int]$aLine[$c])
                                }
                            }
                            $iPropertyIndex++
                        }
                    }
                    [pscustomobject]$oActiveConnection
                }
            }
        }

        function Get-EphemeralPortStats ($ArrayOfComputerNames, $epsUser, $epsPassword, $epsCredential) {
            $epsHtDynamicPortRange = @{}

            foreach ($Computer in $ArrayOfComputerNames) {
                if ($epsHtDynamicPortRange.ContainsKey($Computer) -eq $false) {
                    $oDynamicPortRange = Get-TcpDynamicPortRange -tdprComputer $Computer -tdprUser $epsUser -tdprPassword $epsPassword -tdprCredential $epsCredential
                    [Void]$epsHtDynamicPortRange.Add($Computer, $oDynamicPortRange)
                } else {
                    $oDynamicPortRange = $epsHtDynamicPortRange[$Computer]
                }

                [int]$iDynamicStartPort = $oDynamicPortRange.StartPort
                [int]$iDynamicEndPort = $oDynamicPortRange.EndPort
                [int]$iDynamicNumberOfPorts = $oDynamicPortRange.NumberOfPorts

                $oActiveConnections = Get-ActiveTcpConnections -atcComputer $Computer -atcUser $epsUser -atcPassword $epsPassword -atcCredential $epsCredential | Sort LocalPort -Descending
                $aUniqueLocalAddresses = @($oActiveConnections | Sort {[version]$_.LocalAddress} | Select LocalAddress -Unique).where{$_.localaddress -ne '0.0.0.0'}
                $aDynamicPortRangeConnections = @($oActiveConnections).Where{($_.LocalPort -gt $iDynamicStartPort) -and ($_.LocalPort -lt $iDynamicEndPort)}

                foreach ($oUniqueLocalAddress in $aUniqueLocalAddresses) {
                    if ($oUniqueLocalAddress.LocalAddress -ne '0.0.0.0') {
                        #// Ephemeral ports of each LocalAddress
                        [string]$sUniqueLocalAddress = $oUniqueLocalAddress.LocalAddress
                        [array]$aIpEphemeralPortConnections = @($aDynamicPortRangeConnections).Where{($_.LocalAddress -eq $sUniqueLocalAddress)} | Select LocalPort -Unique | Sort

                        $oStats = @{}
                        $oStats.Add('Computer', $Computer)
                        $oStats.Add('DateTime', $(Get-Date))
                        $oStats.Add('LocalAddress', $sUniqueLocalAddress)
                        $oStats.Add('Max#OfEPorts', [int]$oDynamicPortRange.NumberOfPorts)

                        if ($aIpEphemeralPortConnections -ne $null) {
                            $oStats.Add('#OfEPortsInUse', [int]$aIpEphemeralPortConnections.Count)
                            $iPercentage = [int]$aIpEphemeralPortConnections.Count / [int]$oDynamicPortRange.NumberOfPorts * 100
                            $iPercentage = [Math]::Round($iPercentage, 1)
                        } else {
                            $oStats.Add('#OfEPortsInUse', 0)
                            $iPercentage = 0
                        }

                        $oStats.Add('%EPortUsage', $iPercentage)

                        #// Listening ports of each LocalAddress
                        [array]$aIpListeningPorts = @($oActiveConnections).Where{($_.State -eq 'LISTENING') -and (($_.LocalAddress -eq $sUniqueLocalAddress) -or ($_.LocalAddress -eq '0.0.0.0'))} | Select LocalPort | Sort LocalPort | Get-Unique -AsString

                        if ($aIpListeningPorts -ne $null) {
                            $oStats.Add('#OfTcpListeningPorts', [int]$aIpListeningPorts.Count)
                        } else {
                            $oStats.Add('#OfTcpListeningPorts', 0)
                        }

                        #// Number of PIDs
                        [array]$aIpPids = @($oActiveConnections).Where{($_.LocalAddress -eq $sUniqueLocalAddress) -or ($_.LocalAddress -eq '0.0.0.0')} | Select PID -Unique | Sort PID

                        if ($aIpPids -ne $null) {
                            $oStats.Add('#OfPids', [int]$aIpPids.Count)
                        } else {
                            $oStats.Add('#OfPids', 0)
                        }

                        [pscustomobject]$oStats
                    }
                }
            }
        }
    }

    process {
        $pa = ProcessArguments -paComputers $Computers -paUser $User -paPassword $Password
        $Computers = $pa.computers
        $Credential = $pa.credential

        if ($CollectionInterval) {
            $stop = $false
        } else {
            $stop = $true
        }

        do {
            $oPortStats = Get-EphemeralPortStats -ArrayOfComputerNames $Computers -epsUser $User -epsPassword $Password -epsCredential $Credential

            $oPortStats | Format-Table -AutoSize

            if ($OutputFilePath) {
                $oPortStats | Export-Csv $OutputFilePath -NoTypeInformation
            }

            if ($CollectionInterval) {
                Write-Host "Sleeping for $CollectionInterval seconds..." -NoNewline
                Start-Sleep -Seconds $CollectionInterval
            }

            Write-Host 'Done!'
        } until ($stop)
    }
}

Get-PortStats -Computers $env:computername -OutputFilePath c:\temp\portstats.csv -PsExecLocation C:\PSTools\PsExec.exe