ip_scan.ps1

<#
.SYNOPSIS
  Scan an IP range and report how many IPs are alive.
  
.DESCRIPTION
  Uses Multi Threading and only 1 ping to accomplish the task faster. (Inspired by Angry IP SCanner)

.PARAMETER <Parameter_Name>
   In the top of the script, set your IP ranges. You can scan multiple ranges. Handy for corporate nets.
	
.INPUTS
  None
  
.OUTPUTS
  Text to Powershell Console
  
.NOTES

         Version: 1.01
          Author: Gordon Virasawmi
          GitHub: https://github.com/GordonVi
   Creation Date: 10/25/2019 @ 6:56pm
  Purpose/Change: Initial script development
         License: Free for all. Too simple to charge for. Too important to not publish.
     Works Cited: Runspaces Simplified - https://blog.netnerds.net/2016/12/runspaces-simplified/


.EXAMPLE
  .\ip_scan.ps1
  
#>

# --------------------------------------------------

$threads = 1000 # how many simultanious threads. I've tested up to 1000 ok against ~3600 local IPs, ~900 active.

$list = for ($a=1; $a -le 255; $a++) # set the last octlet range
			{
				"10.0.0.$a" # set the first 3 octlets.
			}

# --------------------------------------------------
	
clear

""
write-host "       Threads: " -nonewline -foregroundcolor yellow
$threads
"    Build Pool: "
"    Drain Pool: "
" ---------------------"
write-host "   Total Hosts: $($list.count)"
write-host "   Alive Hosts: "
write-host "    Dead Hosts: "


# BLOCK 1: Create and open runspace pool, setup runspaces array with min and max threads
$pool = [RunspaceFactory]::CreateRunspacePool(1, $threads)
$pool.ApartmentState = "MTA"
$pool.Open()
$runspaces = $results = @()

# --------------------------------------------------
    
# BLOCK 2: Create reusable scriptblock. This is the workhorse of the runspace. Think of it as a function.
$scriptblock = {
    Param (
    [string]$ip
    )

	$ping=$(Test-Connection -ComputerName $ip -Count 1).scope.isconnected
	if ($ping -eq "true") {
	
							$DNS=([System.Net.Dns]::GetHostByAddress($ip)).Hostname
							#$mac=$($(arp -a $ip)[3]).Split(" ",[System.StringSplitOptions]::RemoveEmptyEntries)[1]
							$mac=$(get-netneighbor -ipaddress $ip).LinkLayerAddress
							
							} else {

							$DNS=""
							$mac=""
							}
       
    # return whatever you want, or don't.
    return [pscustomobject][ordered]@{
								ip 		= $ip
								ping 	= $ping
								DNS		= $DNS
								MAC		= $mac
							} 
}

# --------------------------------------------------
 
# BLOCK 3: Create runspace and add to runspace pool
$counter=0
foreach ($ip in $list) {
 
    $runspace = [PowerShell]::Create()
    $null = $runspace.AddScript($scriptblock)
    $null = $runspace.AddArgument($ip)

    $runspace.RunspacePool = $pool
 
# BLOCK 4: Add runspace to runspaces collection and "start" it
    # Asynchronously runs the commands of the PowerShell object pipeline
    $runspaces += [PSCustomObject]@{ Pipe = $runspace; Status = $runspace.BeginInvoke() }

	$Host.UI.RawUI.CursorPosition = New-Object System.Management.Automation.Host.Coordinates 16 , 2
	$counter++
	write-host "$counter " -nonewline
}

# --------------------------------------------------
 
# BLOCK 5: Wait for runspaces to finish

<#

do {

	$Host.UI.RawUI.CursorPosition = New-Object System.Management.Automation.Host.Coordinates 5 , 9
	$cnt = ($runspaces | Where {$_.Result.IsCompleted -ne $true}).Count
	write-host "$cnt   "
	
	} while ($cnt -gt 0)

#>

# --------------------------------------------------

$total=$counter
$counter=0

# BLOCK 6: Clean up
foreach ($runspace in $runspaces ) {
    # EndInvoke method retrieves the results of the asynchronous call
    $results += $runspace.Pipe.EndInvoke($runspace.Status)
    $runspace.Pipe.Dispose()
	
	$Host.UI.RawUI.CursorPosition = New-Object System.Management.Automation.Host.Coordinates 16 , 3
	$counter++
	write-host "$($total-$counter) " -nonewline

}
    
$pool.Close() 
$pool.Dispose()

# --------------------------------------------------
 
# Bonus block 7
# Look at $results to see any errors or whatever was returned from the runspaces

# Use this to output to JSON. CSV works too since it's simple data.
# $results | convertto-json -depth 10 > ip_scan.json

$total=$results.count
$alive = $($results | ? {$_.ping -eq "true"}).count
$dead = $($results | ? {$_.ping -ne "true"}).count

$Host.UI.RawUI.CursorPosition = New-Object System.Management.Automation.Host.Coordinates 0 , 5

write-host "   Total Hosts: " -nonewline -foregroundcolor cyan
$total

write-host "   Alive Hosts: " -nonewline -foregroundcolor green
$alive

write-host "    Dead Hosts: " -nonewline -foregroundcolor red
$dead

""

$results | ? {$_.ping -eq "true"} | select ip,DNS,MAC