Archive for March, 2014

Remote Powershell in domain environment

March 21st, 2014 3 comments

Sometimes you need to run some command on remote computer. If you don’t want to bother user using Remote Assistance or user is not at the computer you can try Remote Powershell. Powershell was new feature when Windows Vista and Windows Server 2008 came. So we can divide operating systems into three categories. Each category requires some things and some requirements.

Windows 7 / Windows Server 2008 R2 and higher

  • Needs to open ports in firewall (is your firewall is not open all the way)
  • Needs to enable and configure WinRM
  • Needs to configure WinRM service to run

Windows Vista / Windows Server 2008

  • Needs everything from first group
  • Needs to install PowerShell 2.0

Windows XP / Windows Server 2003

  • Needs everything from second group
  • Needs to install .NET Framework

Probably your environment will be mixed of all three types of operating systems. So let’s look how to configure it. I will use GPOs everywhere it can be used.

Enable Remote PowerShell for Windows Vista and Windows Server 2008

Create GPO and set following:

Computer Configuration > Policies > Administrative Templates > Windows Components > Windows Remote Management (WinRM) > WinRM Service > Allow automatic configuration of listeners (Allow Remote Server management through WinRM):

Firewall exceptions

Firewall exceptions for Windows 7 / Windows Server 2008 and higher

If you have Microsoft firewall closed and you need to make exception using GPO in Computer Configuration > Policies > Administrative Templates > Network > Network Connections > Windows Firewall > Domain Profile > Windows Firewall: Define inbound port exceptions:

Firewall exceptions for Windows XP / Windows Server 2003

You have to define New Firewall rule under Computer Configuration > Policies > Windows Settings > Security Settings > Windows Firewall with Advanced Security > Windows Firewall with Advanced Security > Inbound Rules and create new Inbound rule with predefined type “Windows Remote Management”:

Configure Service

To enable Remote Powershell I need to configure service. WinRM service has to start automatically. Create new setting in GPO in Computer Configuration > Policies > Windows Settings > Security Settings > System Services. Setup service Windows Remote Management (WS-Management) following way:

Let’s change startup for this service using GPO settings under Computer Configuration > Preferences > Control Panel Settings > Services. Create new Service setting with following settings:

Windows XP / Windows 2003 specialities

To make Powershell work remotely on older operating systems you need to make sure your operating systems have installed two hotfixes: KB968930 and KB951847. These hotfixes are distibuted via Windows Updates so if you use WSUS, there updates are already on your older operating systems.

To enable PowerShell for remote connection you need to enable it using startup script. So you need to create new GPO which will run only on older OS. You can use following WMI filter to make this GPO apply only on older OS:

You can use following script as a startup script to enable Powershell Remote for Windows XP.

To test it you can run following command:

Enter-PSSession -ComputerName COMPUTER_NAME

Active Directory Users and Computes Implementation

To make it look better you can implement connection to computer using Active Directory Users and Computers.

On location \\domain.local\NETLOGON create new Powershell.vbs file:

' ' Script to run Remote Powershell on domain computer '

Set wshArguments = WScript.Arguments Set objComputer = GetObject(wshArguments(0))

' ' Check if Remote Assistance is installed '

Set fso = CreateObject("Scripting.FileSystemObject") 
If (fso.FileExists("C:\Windows\system32\WindowsPowerShell\v1.0\powershell.exe")) Then  
' Is istalled  
   Set objShell = WScript.CreateObject("WScript.Shell")  
   Return = objShell.Run("C:\Windows\system32\WindowsPowerShell\v1.0\powershell.exe -noexit \\domain.local\NETLOGON\Remote_Session.ps1" & objComputer.dNsHostName, 1, false) 
   ' Is not installed, error.  
   Wscript.Echo "Microsoft Remote PowerShell is not enabled on this machine." 
End If

On location \\domain.local\NETLOGON create new Remote_Session.ps1 file:


Enter-PSSession -ComputerName $computername

 When files are ready, you need to create new record in Active Directory using adsiedit.msc. Connecto to configuration partition of your domain:

Go to Configuration > CN=Configuration,DC… > CN=DisplaySpecifiers > CN=409 > CN=computer-Display and edit property called adminContextMenu.

Add another record into existing list of records. I used following record:

3, &PowerShell Remote,\\domain.local\NETLOGON\Powershell.vbs

which means:

3 – order of record in the list of records (if you have only one existing record, your number will be 2)

&PowerShell Remote – name of the item in context menu

\\domain.local\NETLOGON\Powershell.vbs – path to vbs script you created

Here is how it looks in one of the environments:

When all is done, your Active Directory Users and Computers console has to be reopened and you will find new record under computer account:

When you click on this new item in context menu new powershell window opens. This powershell window is remote powershell windows from remote computer.

I hope people start using powershell more often,

Broken ForestPrep

March 19th, 2014 1 comment

Friend of mine tried to promote Windows Server 2012 into Windows Server 2003 SBS environment. He had installed Windows Server 2012 Server. He also installed role Active Directory Domain Services. When he tried to promote new installed Windows Server 2012 into existing SBS domain he received following error:

Error was generated while Windows Server 2012 tried to do preparation of AD forest. So I have tried to do it using command line:

So same error (Adprep could not retrieve data from the server through Windows Managment Instrumentation WMI). Some problem with WMI on existing domain controller. I have tried to rebuild WMI from scratch using this article. No luck. Message saying “Access is denied” was not true, because account used to run setup.exe /forestprep was Enterprise, Domain and Schema Admin. When I read this article I found out that DCOM has to be enabled and accessible when doing domain controller promotion. So I looked into configuration of old domain controller following way:

Run command dcomcnfg.exe

Browse down to Component Services -> Computers -> My Computer. Right click and select Properties. I found that DCOM was disabled:

So I enabled it with following settings:

…and I was able to promote Windows Server 2012 as a new domain controller. No more access or WMI errors.

This was really hard one to find out 🙂

DNS netmask ordering

March 19th, 2014 No comments

One customer has two physical locations. Here is following IP setting for both locations:

Location 1 – IP range and wpad server is

Location 2 – IP range and wpad server is

When you create two same A records in DNS you get two IP addresses on DNS query. Order of DNS record is changing, because we have Round Robin enabled on our DNS servers. This is default behaviour.  Here is some testing with nslookup:

Same results were in both locations. What we wanted to achieve was that we need DNS servers to return IP address in location Location 1 on first place and IP address in location Location 2 on first place. To make it work we need to look on feature called netmask ordering on DNS servers. You can read more here.

Let’s transfer IP addresses in each location into binary:

00001010.00000000.00000000.00000000 — 00001010.00000000.00000001.11111111

00001010.00000000.00000010.00000000 — 00001010.00000000.00000010.11111111

Networks in both locations are same to 22 bit from begging. First different bit in 23rd. So we need to change netmask ordering on DNS server to use first 23 bits to compare when returning results to client. It means our netmask ordering has to be set to:

00000000.00000000.00000001.11111111 — 0x000001FF

We need to set it on all DNS server and restart DNS service:

Once we do this on server we can see following result in Location 1:

and following result in Location 2:

So now it’s all set and ready to go.

Have a great day,