PowerShell: DHCP settings, leases and reservations inventory


Another day, another PowerShell script.. this time to get DHCP settings, leases and reservations from all DHCP Servers in current domain. Pre-requisite is all DHCP Servers should be Windows 2012 based and WinRM should be enabled on all of them.

# To obtain DHCP Scopes related details from all domain servers
# Author: Nitish Kumar
# v1.0

import-module DHCPServer
#Get all Authorized DCs from AD configuration
$DHCPs = Get-DhcpServerInDC  #| ?{$_.DNSname -like "SINFPS0*" }

$filename = "$Env:userprofile\Desktop\DHCPScopes_DNS_$(get-date -Uformat "%Y%m%d-%H%M%S").csv"
$Report = @()

$Reservations = @()
$k = $null

write-host -foregroundcolor Green "`n`n`n`n`n`n`n`n`n"

foreach ($dhcp in $DHCPs) {
   	$k++
   	Write-Progress -activity "Getting DHCP scopes:" -status "Percent Done: " -PercentComplete (($k / $DHCPs.Count)  * 100) -CurrentOperation "Now processing $($dhcp.DNSName)"
   	$scopes = $null
   	$scopes = (Get-DhcpServerv4Scope -ComputerName $dhcp.DNSName -ErrorAction:SilentlyContinue)	     	
	$Res = $scopes | ForEach {Get-DHCPServerv4Lease -ComputerName $dhcp.DNSName -ScopeID $_.ScopeID} | Select-Object ScopeId,IPAddress,HostName,Description,ClientID,AddressState

	write-host -foregroundcolor Green "Processing reservations on $($dhcp.DNSName)"
	ForEach($Temp in $Res ){
	$Reservation = New-Object -TypeName PSObject -Property @{
       	ServerName = $dhcp.DNSName
		ScopeID = $Temp.ScopeId
		IPAddress = $Temp.IPAddress
		HostName = $Temp.HostName
		Description = $Temp.Description
		ClientID = $Temp.ClientID
		AddressState = $Temp.AddressState        
	} | select-object ServerName, ScopeID, IPAddress, HostName, Description, ClientID, AddressState
	$Reservations += $Reservation
    } 	
	
    If ($scopes -ne $null) {
        $GlobalDNSList = $null        
        #getting global DNS settings, in case scopes are configured to inherit these settings
        $GlobalDNSList = (Get-DhcpServerv4OptionValue -OptionId 6 -ComputerName $dhcp.DNSName -ErrorAction:SilentlyContinue).Value                		
		Try {$Option015 = [String](Get-DhcpServerv4OptionValue -OptionId 015 -ComputerName $dhcp.DNSName -ErrorAction:SilentlyContinue).value}
		Catch {$Option015=''}

        $scopes | % {            
            $row = '' | select Hostname,ScopeID,SubnetMask,Name,State,StartRange,EndRange,LeaseDuration,Description,DNS1,DNS2,DNS3,DNS4,DNS5,GDNS1,GDNS2,GDNS3,GDNS4,GDNS5,Router,DoGroupId,Option160,option015,Scopeoption015,Exclusions
			Try {$DoGroupId = [String](Get-DhcpServerv4OptionValue -OptionId 234 -ScopeID $_.ScopeId -ComputerName $dhcp.DNSName -ErrorAction:SilentlyContinue).value}
			Catch {$DoGroupId=''}

			Try {$Option160 = [String](Get-DhcpServerv4OptionValue -OptionId 160 -ScopeID $_.ScopeId -ComputerName $dhcp.DNSName -ErrorAction:SilentlyContinue).value}
			Catch {$Option160=''}
			
			Try {$ScopeOption015 = [String](Get-DhcpServerv4OptionValue -OptionId 015 -ScopeID $_.ScopeId -ComputerName $dhcp.DNSName -ErrorAction:SilentlyContinue).value}
			Catch {$ScopeOption015=''}
            
			$router = @()		
			Try { $router = (Get-DhcpServerv4OptionValue -ComputerName $dhcp.DNSName -OptionId 3 -ScopeID $_.ScopeId -ErrorAction:SilentlyContinue).Value}
			Catch{ $router = ('')}
			
			$ScopeExclusions = @()	
			Try { $ScopeExclusions = Get-DhcpServerv4ExclusionRange -ComputerName $dhcp.DNSName -ScopeID $_.ScopeId -ErrorAction:SilentlyContinue }
			Catch{ $ScopeExclusions = ('')}
			
			$Exclusions = ''
			$z = 0
			If($ScopeExclusions){
				ForEach($ScopeExclusion in $ScopeExclusions){
					$z++
					write-host "Checking exclusion $($z) for $($_.ScopeId) ..." -Foregroundcolor GREEN
					$ExclusionValue = [String]$ScopeExclusion.StartRange + "-" + [String]$ScopeExclusion.EndRange
					if($z -ge 2){	$Exclusions = $Exclusions + "," + $ExclusionValue} else {$Exclusions = $ExclusionValue}						
				}
			}
			
			$row.Router = $router[0]
			$row.Hostname = $dhcp.DNSName
			$row.ScopeID = $_.ScopeID
			$row.SubnetMask = $_.SubnetMask
			$row.Name = $_.Name
			$row.State = $_.State
			$row.StartRange = $_.StartRange
			$row.EndRange = $_.EndRange
			$row.LeaseDuration = $_.LeaseDuration
			$row.Description = $_.Description			
			$row.DoGroupId = $DoGroupId
			$row.Option160 = $Option160
			$row.Option015 = $Option015
			$row.ScopeOption015 = $ScopeOption015
			$row.Exclusions = $Exclusions
			$ScopeDNSList = $null
			$ScopeDNSList = (Get-DhcpServerv4OptionValue -OptionId 6 -ScopeID $_.ScopeId -ComputerName $dhcp.DNSName -ErrorAction:SilentlyContinue).Value            

			If (($ScopeDNSList -eq $null) -and ($GlobalDNSList -ne $null)) {
				$row.GDNS1 = $GlobalDNSList[0]
				$row.GDNS2 = $GlobalDNSList[1]
				$row.GDNS3 = $GlobalDNSList[2]
				$row.GDNS4 = $GlobalDNSList[3]
				$row.GDNS5 = $GlobalDNSList[4]              
			}
			ElseIf (($ScopeDNSList -ne $null) -and ($GlobalDNSList -ne $null)) {
				$row.GDNS1 = $GlobalDNSList[0]
				$row.GDNS2 = $GlobalDNSList[1]
				$row.GDNS3 = $GlobalDNSList[2]
				$row.GDNS4 = $GlobalDNSList[3]
				$row.GDNS5 = $GlobalDNSList[4]                				
				$row.DNS1 = $ScopeDNSList[0]
				$row.DNS2 = $ScopeDNSList[1]
				$row.DNS3 = $ScopeDNSList[2]
				$row.DNS4 = $ScopeDNSList[3]
				$row.DNS5 = $ScopeDNSList[4]                
			}
			Else {
				$row.DNS1 = $ScopeDNSList[0]
				$row.DNS2 = $ScopeDNSList[1]
				$row.DNS3 = $ScopeDNSList[2]
				$row.DNS4 = $ScopeDNSList[3]
				$row.DNS5 = $ScopeDNSList[4]                
			}	
			$row	
			$Report += $row
		}
	}
    Else {
        write-host -foregroundcolor Yellow "$($dhcp.DNSName) is either running Windows 2003, or is somehow not responding to querries. Adding to report as blank"
        $row = '' | select Hostname,ScopeID,SubnetMask,Name,State,StartRange,EndRange,LeaseDuration,Description,DNS1,DNS2,DNS3,DNS4,DNS5,GDNS1,GDNS2,GDNS3,GDNS4,GDNS5,Router,DoGroupId,Option160,option015,Scopeoption015,Exclusions
        $row.Hostname = $dhcp.DNSName
        $Report += $row
        }
    write-host -foregroundcolor Green "Done Processing $($dhcp.DNSName)"
    }
$Report  | Export-csv -NoTypeInformation -UseCulture $filename
$Reservations | Export-Csv "$Env:userprofile\Desktop\DHCPLeasesReservations_$(get-date -Uformat "%Y%m%d-%H%M%S").csv" -NoTypeInformation

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