This function is a demonstration of multi-tasking using PowerShell. The program will ping multiple targets simultaneously with aggression damping factor of 8-thread maximum. Moreover, hash tables are used extensively for better performance.
Practical application of this script is to perform discovery of a network segment or range of IPs. Once ‘pingable’ nodes are identified, one could avoid assigning such values toward a new computer, network device, or an appliance.
# Usage Examples
1. scanForAvailableIPs -start 192.168.0.1 -end 192.168.0.254
2. scanForAvailableIPs -ip 192.168.0.1 -cidr 24
3. scanForAvailableIPs -ip 192.168.0.1 -mask 255.255.255.0
4. scanForAvailableIPs -cidrBlock '10.10.10.0/22' -limit 100
5. scanForAvailableIPs -cidrBlock '10.10.10.0/22' -getUnavailableIps $true
6. scanForAvailableIps
# scanForAvailableIps_v0.02.ps1
# Requires: Powershell 3.0+
#$cidrBlock='10.17.130.0/23'
$start='10.17.130.101'
$end='10.17.130.254'
$limit=2
function scanForAvailableIPs{
param(
[string]$start,
[string]$end,
[string]$ip,
[string]$mask,
[string]$cidr,
[string]$cidrBlock,
[string]$limit, # Assuming CIDR /16
[string]$getUnavailabeIps=$false
)
function Get-IPrange{
<# This Get-IPrange function has been obtained at Gallery Technet
Snippet Author: BarryCWT
.SYNOPSIS
Get the IP addresses in a range
.EXAMPLE
Get-IPrange -start 192.168.8.2 -end 192.168.8.20
.EXAMPLE
Get-IPrange -ip 192.168.8.2 -mask 255.255.255.0
.EXAMPLE
Get-IPrange -ip 192.168.8.3 -cidr 24
#>
param (
[string]$start,
[string]$end,
[string]$ip,
[string]$mask,
[int]$cidr
)
function IP-toINT64 () {
param ($ip)
$octets = $ip.split(".")
return [int64]([int64]$octets[0]*16777216 +[int64]$octets[1]*65536 +[int64]$octets[2]*256 +[int64]$octets[3])
}
function INT64-toIP() {
param ([int64]$int)
return (([math]::truncate($int/16777216)).tostring()+"."+([math]::truncate(($int%16777216)/65536)).tostring()+"."+([math]::truncate(($int%65536)/256)).tostring()+"."+([math]::truncate($int%256)).tostring() )
}
if ($ip) {$ipaddr = [Net.IPAddress]::Parse($ip)}
if ($cidr) {$maskaddr = [Net.IPAddress]::Parse((INT64-toIP -int ([convert]::ToInt64(("1"*$cidr+"0"*(32-$cidr)),2)))) }
if ($mask) {$maskaddr = [Net.IPAddress]::Parse($mask)}
if ($ip) {$networkaddr = new-object net.ipaddress ($maskaddr.address -band $ipaddr.address)}
if ($ip) {$broadcastaddr = new-object net.ipaddress (([system.net.ipaddress]::parse("255.255.255.255").address -bxor $maskaddr.address -bor $networkaddr.address))}
if ($ip) {
$startaddr = IP-toINT64 -ip $networkaddr.ipaddresstostring
$endaddr = IP-toINT64 -ip $broadcastaddr.ipaddresstostring
} else {
$startaddr = IP-toINT64 -ip $start
$endaddr = IP-toINT64 -ip $end
}
for ($i = $startaddr; $i -le $endaddr; $i++)
{
INT64-toIP -int $i
}
}
# Regex values
$regexIP = [regex] "\b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b"
$regexCidr=[regex] "\/(.*)"
$regexFourthOctetValue=[regex] ".+\..+\..+\.(.+)"
# Process inputs
if ($start -and $end){
$allIPs=Get-IPrange -start $start -end $end
}elseif($ip -and $mask){
$allIPs=Get-IPrange -ip $ip -mask $mask
}elseif($ip -and $cidr){
$allIPs=Get-IPrange -ip $ip -cidr $cidr
}elseif($cidrBlock){
$ip=$regexIP.Matches($cidrBlock).Value
$cidr=$regexCidr.Matches($cidrBlock).Groups[1].Value
$allIPs=Get-IPrange -ip $ip -cidr $cidr
}else{ # This will be the catchall when function is called without any arguments
$cidrBlock=$(
$interfaceIndex=(Get-WmiObject -Class Win32_IP4RouteTable | where { $_.destination -eq '0.0.0.0' -and $_.mask -eq '0.0.0.0'} | Sort-Object metric1).interfaceindex;
$interfaceObject=(Get-NetIPAddress -InterfaceIndex $interfaceIndex -AddressFamily ipv4|select IPAddress,PrefixLength)[0];
"$($interfaceObject.IPAddress)/$($interfaceObject.PrefixLength)")
$ip=$regexIP.Matches($cidrBlock).Value
$cidr=$regexCidr.Matches($cidrBlock).Groups[1].Value
$allIPs=Get-IPrange -ip $ip -cidr $cidr
}
# Remove fourth octet values matching 0,1, and 255
#if($regexFourthOctetValue.Matches($allIPs[0]).Groups[1].Value -eq 0){$first, $rest= $allIPs; $allIPs=$rest;}
#if($regexFourthOctetValue.Matches($allIPs[0]).Groups[1].Value -eq 1){$first, $rest= $allIPs; $allIPs=$rest;}
if($regexFourthOctetValue.Matches($allIPs[$allIPs.length-1]).Groups[1].Value -eq 255){$allIPs = $allIPs | ? {$_ -ne $allIPs[$allIPs.count-1]}}
# Display sweep scanning output
#$allIPs | ForEach-Object {if(!(Get-WmiObject Win32_PingStatus -Filter "Address='$_' and Timeout=200 and ResolveAddressNames='true' and StatusCode=0" | select ProtocolAddress*)){$_}}
# Collect unpingable IPs
"Collecting available IPs. Please wait awhile..."
if(!$limit){$limit=$allIPs.count}
$i=0
$simultaneousJobs=8
$pingCommand={
param($ipAddress)
[bool]$pingable=!(!(Get-WmiObject Win32_PingStatus -Filter "Address='$ipAddress' and Timeout=200 and ResolveAddressNames='true' and StatusCode=0"))
return @{$ipAddress=$pingable}
}
$results=@{}
foreach ($ipAddress in $allIps){
if($i++ -lt $simultaneousJobs){
Start-Job $pingCommand -ArgumentList $ipAddress|Out-Null
}else{
do{
$result=Get-Job | Receive-Job #-Wait
if($result){
$result|%{$_.GetEnumerator()|%{write-host "$($_.Key) pingable`t: $($_.Value)";$results[$_.Key]=$_.Value}}
get-job -State Completed|remove-job
}
$i=(get-job -state 'Running').count
}until($i -lt $simultaneousJobs)
}
$desiredResults=if(!$getUnavailabeIps){$results.GetEnumerator()|?{$_.value}}else{$results.GetEnumerator()|?{!($_.value)}}
if($desiredResults.count -ge $limit){
#write-host "Results count $($desiredResults.count) reached."
write-host "`r`n------------------------------------------`r`nScanner stopped at $($desiredResults.count) as limit of $limit results have been reached." -ForegroundColor Yellow
return $desiredResults.GetEnumerator()|%{$_.Name}|Sort|select -First $limit
}
}
write-host "No results."
return $false
}
scanForAvailableIPs -start $start -end $end -limit $limit
# Sample Output
PS C:\Windows\system32> scanForAvailableIPs -start $start -end $end -limit $limit
Collecting available IPs. Please wait awhile...
10.10.10.221 pingable : True
10.10.10.226 pingable : True
10.10.10.229 pingable : True
10.10.10.201 pingable : True
10.10.10.202 pingable : False
10.10.10.203 pingable : False
10.10.10.204 pingable : False
10.10.10.205 pingable : True
10.10.10.206 pingable : False
10.10.10.207 pingable : False
10.10.10.208 pingable : False
10.10.10.210 pingable : False
10.10.10.211 pingable : False
10.10.10.212 pingable : True
10.10.10.213 pingable : True
10.10.10.214 pingable : False
10.10.10.215 pingable : True
10.10.10.216 pingable : False
10.10.10.218 pingable : False
10.10.10.219 pingable : False
10.10.10.220 pingable : False
10.10.10.222 pingable : True
10.10.10.223 pingable : True
10 of 14 desired results have been collected
10.10.10.202
10.10.10.203
10.10.10.204
10.10.10.206
10.10.10.207
10.10.10.208
10.10.10.210
10.10.10.211
10.10.10.214
10.10.10.216
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