Solved

How to programatically query DNS for records soon to expire / be scavenged?

Posted on 2008-06-11
4
882 Views
Last Modified: 2013-12-01
I would like to know if there is a way I can programatically query a windows based DNS server for records that have failed to be reregistered in a certain time frame and thus up for expiration and scavenging?

Is there a query-language for DNS? How does one use it to find this sort of information?

An example would be wonderful in c# or vb or a scripting language... anything, really.
0
Comment
Question by:DefyFate05
  • 3
4 Comments
 
LVL 70

Expert Comment

by:Chris Dent
ID: 21773436

Hey there,

It's all exposted in WMI.

I have VbScript or PowerShell versions to find this kind of thing. The PowerShell version is a hell of a lot neater / more flexible / more reliable.

Copy and paste this, fixing the Domain Name and Server Name.

Listing All Stale Records within a given Domain:

$DNSServer = "YourServerName"
$Domain = "YourDomain"

Get-WMIObject -Class "MicrosoftDNS_AType" -Namespace `
    "root\MicrosoftDNS" -Comp $DNSServer -Filter "DomainName='$Domain'" | `
    Select-Object `
    OwnerName,@{n="TimeStamp";e={(Get-Date("01/01/1601")).AddHours($_.TimeStamp)}} `
    | ?{($_.TimeStamp -lt ((Get-Date).AddDays(-14))) -and ($_.TimeStamp -ne (Get-Date("01/01/1601")))}

Note the use of "AddDays(-14)", that means we're only looking for entries where the TimeStamp is more than 14 days old, it assumes you're using 7 Days No-Refresh and 7 Days Refresh, change as appropriate.

HTH

Chris
0
 
LVL 70

Expert Comment

by:Chris Dent
ID: 21773447

Oh yeah, just for interest, this is a modification of it to show Static Records:

$DNSServer = "YourServerName"
$Domain = "YourDomain"

Get-WMIObject -Class "MicrosoftDNS_AType" -Namespace `
    "root\MicrosoftDNS" -Comp $DNSServer -Filter "DomainName='$Domain'" | `
    Select-Object `
    OwnerName,@{n="TimeStamp";e={(Get-Date("01/01/1601")).AddHours($_.TimeStamp)}} `
    | ?{$_.TimeStamp -eq (Get-Date("01/01/1601"))}

TimeStamp is always 0 for Static Records, so the adjusted time always ends up being 01/01/1601.

Chris
0
 

Author Comment

by:DefyFate05
ID: 21775939
Can you throw the vbscript version up?

0
 
LVL 70

Accepted Solution

by:
Chris Dent earned 250 total points
ID: 21776839

Certainly, here we go.

Chris
' No-Refresh + Refresh
Const MAXIMUM_AGE = 4
 
' DNS Server Name ("." if run locally)
Const SERVER_NAME = "."
 
' Domain Name to check 
' WMI query returns A records from all zones without WHERE filter
' Domain Name should be lower case and should not include trailing "."
Const DOMAIN_NAME = "domain.local"
 
Set objWMIService = GetObject("winmgmts:\\" & SERVER_NAME & "\root\MicrosoftDNS")
 
Set colItems = objWMIService.ExecQuery("SELECT * FROM MicrosoftDNS_AType WHERE " &_
        "DomainName='" & DOMAIN_NAME & "'")
 
Set objFileSystem = CreateObject("Scripting.FileSystemObject")
Set objFile = objFileSystem.OpenTextFile("StaleRecords.csv", 2, True, 0)
 
objFile.WriteLine "FQDN,IPAddress,TimeStamp"
 
For Each objItem In colItems
	' If InStr(1, objItem.DomainName, DOMAIN_NAME, VbTextCompare) > 0 Then
	        If objItem.TimeStamp > 0 Then
        	        dtmTimeStamp = DateAdd("h", objItem.TimeStamp, "1/1/1601 00:00:00 AM")
 
 
 	               If dtmTimeStamp <= (Date - MAXIMUM_AGE) Then
                	        objFile.WriteLine objItem.OwnerName & "," & objItem.IPAddress &_
        	                        "," & dtmTimeStamp
	                End If
        	End If
	' End If
Next
 
Set objFile = Nothing
Set objFileSystem = Nothing
 
Set colItems = Nothing
Set objWMIService = Nothing

Open in new window

0

Featured Post

Optimizing Cloud Backup for Low Bandwidth

With cloud storage prices going down a growing number of SMBs start to use it for backup storage. Unfortunately, business data volume rarely fits the average Internet speed. This article provides an overview of main Internet speed challenges and reveals backup best practices.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Welcome to my series of short tips on migrations. Whilst based on Microsoft migrations the same principles can be applied to any type of migration. My first tip Migration Tip #1 – Source Server Health can be found listed in my profile here: http:…
Today, still in the boom of Apple, PC's and products, nearly 50% of the computer users use Windows as graphical operating systems. If you are among those users who love windows, but are grappling to keep the system's hard drive optimized, then you s…
Email security requires an ever evolving service that stays up to date with counter-evolving threats. The Email Laundry perform Research and Development to ensure their email security service evolves faster than cyber criminals. We apply our Threat…

828 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question