Question:
I’m using PowerShell to extract information from an Active Directory DNS server and I’m having trouble getting to the data I want.
Specifically, I’m trying to get the names of hosts that belong to a particular subnet, 10.104.128.x.
When I use the following commands:
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Get-DnsServerResourceRecord -ComputerName AD_DNS_SERVER -ZoneName 104.10.in-addr.arpa -RRType Ptr | Where-Object {$_.HostName -like '*.128'}` |
I get output that looks like this:
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HostName RecordType Timestamp TimeToLive RecordData -------- ---------- --------- ---------- ---------- 104.128 PTR 10/19/2015 3:00:0... 00:15:00 adl5c260a86ba79.XYZ.net. 11.128 PTR 12/29/2015 6:00:0... 00:15:00 adl3c970e8d7166.XYZ.net. 110.128 PTR 1/29/2012 11:00:0... 00:15:00 nroxitow7tst.ABC.com. 114.128 PTR 1/20/2012 7:00:00 AM 00:15:00 adl5c260a86c29e.ABC.com |
What I really want are the first column, (HostName), which has the last two octets of the IP; and the fifth column, (RecordData), which has the name of the host the IP is assigned to.
The hostname is the data I really want/need. And I see it right there!
So I used the select command to pare down the output in the pipe train. New command looks like this:
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Get-DnsServerResourceRecord -ComputerName AD_DNS_SERVER -ZoneName 104.10.in-addr.arpa -RRType Ptr | Where-Object {$_.HostName -like '*.128'} | select HostName, RecordData |
But the output looks like this:
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HostName RecordData -------- ---------- 104.128 DnsServerResourceRecordPtr 11.128 DnsServerResourceRecordPtr 110.128 DnsServerResourceRecordPtr 114.128 DnsServerResourceRecordPtr |
Dosen’t get me the hostname though. Just the type of object the RecordData is but not the data that the object contains, perhaps?
I also tried piping the output to CSV and got the same result.
Then I tried looking at the DnsServerResourceRecord object properties with Get-Member. That showed me the object had a property called PSComputerName. I thought maybe that would have the name of the host but that came up blank when I tried to select it.
I then Googled around a bit and found a few pages that recommended a few ways to use RecordData.ipv4address to coax the data out of the DnsServerResourceRecordPtr object but I haven’t gotten any of them to work yet. Output still prints blanks.
So my question is: does a reliable method exist for getting the actual hostname from a PTR record?
Answer:
To select the PtrDomainName property from the DnsServerResourceRecordPtr object, use a calculated property:
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... |Select-Object HostName, @{Name='RecordData';Expression={$_.RecordData.PtrDomainName}} |