Public/Network/NetworkInfo/Get-LocalPort.ps1

function Get-LocalPort {
  <#
.SYNOPSIS
    This parses the native netstat.exe's output using the command line "netstat -anb" to find
    all of the network ports in use on a local machine and all associated processes and services
.NOTES
    Created on: 2/15/2015
    Created by: Adam Bertram
    Filename: Get-LocalPort.ps1
.EXAMPLE
    PS> Get-LocalPort.ps1

    This example will find all network ports in uses on the local computer with associated
    processes and services

.EXAMPLE
    PS> Get-LocalPort.ps1 | Where-Object {$_.ProcessOwner -eq 'svchost.exe'}

    This example will find all network ports in use on the local computer that were opened
    by the svchost.exe process.

.EXAMPLE
    PS> Get-LocalPort.ps1 | Where-Object {$_.IPVersion -eq 'IPv4'}

    This example will find all network ports in use on the local computer using IPv4 only.
#>

  [CmdletBinding()]
  param ()

  begin {
    #Requires -Version 3
    Set-StrictMode -Version Latest
    $ErrorActionPreference = 'Stop'
  }

  process {
    try {
      ## Capture the output of the native netstat.exe utility
      ## Remove the top row from the result and trim off any leading or trailing spaces from each line
      ## Replace all instances of more than 1 space with a pipe symbol. This allows easier parsing of
      ## the fields
      $Netstat = (netstat -anb | Where-Object { $_ -and ($_ -ne 'Active Connections') }).Trim() | Select-Object -Skip 1 | ForEach-Object { $_ -replace '\s{2,}', '|' }

      $i = 0
      foreach ($Line in $Netstat) {
        ## Create the hashtable to conver to object later
        $Out = @{
          'Protocol'      = ''
          'State'         = ''
          'IPVersion'     = ''
          'LocalAddress'  = ''
          'LocalPort'     = ''
          'RemoteAddress' = ''
          'RemotePort'    = ''
          'ProcessOwner'  = ''
          'Service'       = ''
        }
        ## If the line is a port
        if ($Line -cmatch '^[A-Z]{3}\|') {
          $Cols = $Line.Split('|')
          $Out.Protocol = $Cols[0]
          ## Some ports don't have a state. If they do, there's always 4 fields in the line
          if ($Cols.Count -eq 4) {
            $Out.State = $Cols[3]
          }
          ## All port lines that start with a [ are IPv6
          if ($Cols[1].StartsWith('[')) {
            $Out.IPVersion = 'IPv6'
            $Out.LocalAddress = $Cols[1].Split(']')[0].TrimStart('[')
            $Out.LocalPort = $Cols[1].Split(']')[1].TrimStart(':')
            if ($Cols[2] -eq '*:*') {
              $Out.RemoteAddress = '*'
              $Out.RemotePort = '*'
            } else {
              $Out.RemoteAddress = $Cols[2].Split(']')[0].TrimStart('[')
              $Out.RemotePort = $Cols[2].Split(']')[1].TrimStart(':')
            }
          } else {
            $Out.IPVersion = 'IPv4'
            $Out.LocalAddress = $Cols[1].Split(':')[0]
            $Out.LocalPort = $Cols[1].Split(':')[1]
            $Out.RemoteAddress = $Cols[2].Split(':')[0]
            $Out.RemotePort = $Cols[2].Split(':')[1]
          }
          ## Because the process owner and service are on separate lines than the port line and the number of lines between them is variable
          ## this craziness was necessary. This line starts parsing the netstat output at the current port line and searches for all
          ## lines after that that are NOT a port line and finds the first one. This is how many lines there are until the next port
          ## is defined.
          $LinesUntilNextPortNum = ($Netstat | Select-Object -Skip $i | Select-String -Pattern '^[A-Z]{3}\|' -NotMatch | Select-Object -First 1).LineNumber
          ## Add the current line to the number of lines until the next port definition to find the associated process owner and service name
          $NextPortLineNum = $i + $LinesUntilNextPortNum
          ## This would contain the process owner and service name
          $PortAttribs = $Netstat[($i + 1)..$NextPortLineNum]
          ## The process owner is always enclosed in brackets of, if it can't find the owner, starts with 'Can'
          $Out.ProcessOwner = $PortAttribs -match '^\[.*\.exe\]|Can'
          if ($Out.ProcessOwner) {
            ## Get rid of the brackets and pick the first index because this is an array
            $Out.ProcessOwner = ($Out.ProcessOwner -replace '\[|\]', '')[0]
          }
          ## A service is always a combination of multiple word characters at the start of the line
          if ($PortAttribs -match '^\w+$') {
            $Out.Service = ($PortAttribs -match '^\w+$')[0]
          }
          [pscustomobject]$Out
        }
        ## Keep the counter
        $i++
      }
    } catch {
      Write-Error "Error: $($_.Exception.Message) - Line Number: $($_.InvocationInfo.ScriptLineNumber)"
    }
  }
}