Export Subnets from Active Directory Sites and Services

I was asked if I could produce all the subnets from our environment. I was quick to turn to PowerShell for this request. As long as you have all of your subnets properly associated to sites in Active Directory, PowerShell can be utilized to get you the subnets. The commands to grab this information depend on the operating system you are running so I provided both methods.

If you are using Windows 7/2008 you can use the following method:

Step #1: The following command produces a list of all the Active Directory sites and their details.

[System.DirectoryServices.ActiveDirectory.Forest]::GetCurrentForest().Sites

Step #2: Now we just need to assign the command a variable allowing us to select and extract the subnets from it’s properties. We utilize a custom object and a foreach loop that will add each subnet and site name to the list.

$sites = [System.DirectoryServices.ActiveDirectory.Forest]::GetCurrentForest().Sites

$sitesubnets = @()

foreach ($site in $sites)
{
	foreach ($subnet in $site.subnets){
	   $temp = New-Object PSCustomObject -Property @{
	   'Site' = $site.Name
	   'Subnet' = $subnet; }
	    $sitesubnets += $temp
	}
}

$sitesubnets

Step #3: If you would like to export this information to a spreadsheet simply add an Export-CSV to the pipeline.

$sites = [System.DirectoryServices.ActiveDirectory.Forest]::GetCurrentForest().Sites

$sitesubnets = @()

foreach ($site in $sites)
{
	foreach ($subnet in $site.subnets){
	   $temp = New-Object PSCustomObject -Property @{
	   'Site' = $site.Name
	   'Subnet' = $subnet; }
	    $sitesubnets += $temp
	}
}

$sitesubnets | Export-CSV subnet.csv

If you are running Windows 8/Windows Server 2012 life is a bit easier as you can use the built in Active Directory commandlets for managing Active Directory sites and services. Simply install the Active Directory modules or run them from the domain controller with the following commandlets. You will have to ensure your Domain Controller is running Active Directory Web Services if you plan on running these remotely.

Step #1: The following command returns all the subnets in Active Directory Sites and Services.

Get-ADReplicationSubnet -Filter *

Step #2: Now we simply have to select the appropriate properties that we want to include. In this case I chose the Name of the subnet and the Site.

Get-ADReplicationSubnet -Filter * | Select-Object Name, Site

Step #3: If you would like to export this information to a spreadsheet simply add an Export-CSV to the pipeline.

Get-ADReplicationSubnet -Filter * | Select-Object Name, Site | Export-CSV subnets.csv

I hope you ran across this and found it useful. Feel free to leave a comment with your problem or need and I will update the post with the solution.