Today, I’m writing about a simple-but-useful command that just might help you get a better understanding of the quantity and variety of Windows servers you have in your environment, with just a few caveats. The most accurate way to get such information, of course, is to query Active Directory in real-time to get the most current information possible. And the easiest way to do that (in my opinion), is to use PowerShell. So launch a console and let’s get to it…
But first, if you haven’t launched the pre-loaded Active-Directory PowerShell Module, then let’s do that now:
Here’s a first blush at how we can list all AD-based computers, grabbing only the interesting properties we need, formatting the output to a list, and redirecting the results to file (I’ve seen some things like this while ‘Googling):
Get-AdComputer -Filter * -Properties IPv4Address,OperatingSystem,OperatingSystemServicePack | Format-List Name, IPv4Address, OperatingSystem* > OutputServerList.txt
Now, let’s dig deeper, and perhaps refine the command a bit. First, the filter is a wildcard, and retrieves all computers. That might be fine in a small environment with few computers; but we’re really only after Servers here, and we might be working in a larger environment. So, we will change the filter to use an LDAPFilter and get a bit more granular like this:
Next, I think the results will actually look better if we output them to a CSV, so we’ll drop the redirect and list formatting, and replace it with a pipe like this:
| Export-Csv ExportCsvServerList.csv
Now a warning about the CSV export… Unfortunately, Microsoft chose to include a “restricted” symbol (little r in a circle) in the Server 2008 (non-R2) name, like this:
Windows Server® 2008 Standard
…and, the CSV export operates only with the ASCII set by default. Sheesh. So, we use the UTF8 flag to make sure the wacky “restricted” mark is rendered correctly, like this:
| Export-Csv -Encoding UTF8 ExportCsvServerList.csv
So with all that, we end up with a command looking like this:
Get-AdComputer -LDAPFilter "(OperatingSystem=*Server*)" -Properties IPv4Address,OperatingSystem,OperatingSystemServicePack,OperatingSystemVersion | Export-Csv -Encoding UTF8 ExportCsvServerList.csv
And since it’s a spreadsheet you can further filter/format/manipulate the results how you see fit.
One more thing that causes confusion sometimes:
Be aware that even though we are calling ActiveDirectory for these servers and their correlating properties, there’s one of these items that don’t come from there: the IP Address. As you are likely aware, the IP address of a computer object is not stored in the directory; so what is actually happening is that the Get-AdComputer module is retrieving the FQDN of the computer, and doing a DNS query to resolve it to the address for you.
Now, this can be good or bad, depending on your situation; for instance, it might slow down your 8000+ server export… or might also help alleviate the burden on your AD server as you make the query (while it delays the processing a tad to retrieve the name). Also, you’d better be able to rely on your DNS to return valid values, or the results might be confusing/misleading!
I hope that helps… Thanks for reading, and by all means if you have additional tips, be sure to comment!
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Tags: CSV, DNS, Export-CSV, Get-AdComputer, LDAPFilter, nslookup, Powershell, PowerShellv2, PowerShellv3, script, UTF8