Public/Network/Get-IpRange.ps1
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function Get-IpRange { <# .SYNOPSIS Given a subnet in CIDR format, get all of the valid IP addresses in that range. .DESCRIPTION Given a subnet in CIDR format, get all of the valid IP addresses in that range. .PARAMETER Subnets The subnet written in CIDR format 'a.b.c.d/#' and an example would be '192.168.1.24/27'. Can be a single value, an array of values, or values can be taken from the pipeline. .EXAMPLE Get-IpRange -Subnets '192.168.1.24/30' 192.168.1.25 192.168.1.26 .EXAMPLE (Get-IpRange -Subnets '10.100.10.0/24').count 254 .EXAMPLE '192.168.1.128/30' | Get-IpRange 192.168.1.129 192.168.1.130 .NOTES Inspired by https://gallery.technet.microsoft.com/PowerShell-Subnet-db45ec74 * Added comment help #> [CmdletBinding(ConfirmImpact = 'None')] Param( [Parameter(Mandatory, HelpMessage = 'Please enter a subnet in the form a.b.c.d/#', ValueFromPipeline, Position = 0)] [string[]] $Subnets ) begin { Write-Invocation $MyInvocation } process { foreach ($subnet in $subnets) { if ($subnet -match '^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}/\d{1,2}$') { #Split IP and subnet $IP = ($Subnet -split '\/')[0] [int] $SubnetBits = ($Subnet -split '\/')[1] if ($SubnetBits -lt 7 -or $SubnetBits -gt 30) { Write-Error -Message 'The number following the / must be between 7 and 30' break } #Convert IP into binary #Split IP into different octects and for each one, figure out the binary with leading zeros and add to the total $Octets = $IP -split '\.' $IPInBinary = @() foreach ($Octet in $Octets) { #convert to binary $OctetInBinary = [convert]::ToString($Octet, 2) #get length of binary string add leading zeros to make octet $OctetInBinary = ('0' * (8 - ($OctetInBinary).Length) + $OctetInBinary) $IPInBinary = $IPInBinary + $OctetInBinary } $IPInBinary = $IPInBinary -join '' #Get network ID by subtracting subnet mask $HostBits = 32 - $SubnetBits $NetworkIDInBinary = $IPInBinary.Substring(0, $SubnetBits) #Get host ID and get the first host ID by converting all 1s into 0s $HostIDInBinary = $IPInBinary.Substring($SubnetBits, $HostBits) $HostIDInBinary = $HostIDInBinary -replace '1', '0' #Work out all the host IDs in that subnet by cycling through $i from 1 up to max $HostIDInBinary (i.e. 1s stringed up to $HostBits) #Work out max $HostIDInBinary $imax = [convert]::ToInt32(('1' * $HostBits), 2) - 1 $IPs = @() #Next ID is first network ID converted to decimal plus $i then converted to binary For ($i = 1 ; $i -le $imax ; $i++) { #Convert to decimal and add $i $NextHostIDInDecimal = ([convert]::ToInt32($HostIDInBinary, 2) + $i) #Convert back to binary $NextHostIDInBinary = [convert]::ToString($NextHostIDInDecimal, 2) #Add leading zeros #Number of zeros to add $NoOfZerosToAdd = $HostIDInBinary.Length - $NextHostIDInBinary.Length $NextHostIDInBinary = ('0' * $NoOfZerosToAdd) + $NextHostIDInBinary #Work out next IP #Add networkID to hostID $NextIPInBinary = $NetworkIDInBinary + $NextHostIDInBinary #Split into octets and separate by . then join $IP = @() For ($x = 1 ; $x -le 4 ; $x++) { #Work out start character position $StartCharNumber = ($x - 1) * 8 #Get octet in binary $IPOctetInBinary = $NextIPInBinary.Substring($StartCharNumber, 8) #Convert octet into decimal $IPOctetInDecimal = [convert]::ToInt32($IPOctetInBinary, 2) #Add octet to IP $IP += $IPOctetInDecimal } #Separate by . $IP = $IP -join '.' $IPs += $IP } Write-Output -InputObject $IPs } else { Write-Error -Message "Subnet [$subnet] is not in a valid format" } } } end { Out-Verbose $fxn "Complete." } } |