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Archive for September, 2008


Next to ADFIND.EXE, LDP is the tool I probably use most often when working with Active Directory.  It’s an LDAP client that was originally developed for use purely within Microsoft. It can be used for browsing, searching and making changes via the LDAP protocol.  Because of its usefulness, Microsoft included LDP in the Support Tools in Windows 2000 and Windows Server 2003.  It has now gone mainstream and is included as part of the Windows Server 2008 installation. 

Here are some of the improvements I have become aware of in the Windows Server 2008 version of LDP.  Note that with the exception of the help documentation, these improvements were first introduced in the versions of LDP that shipped with ADAM in Windows Server 2003 R2 and with the ADAM SP1 download.

Bind as currently logged on user

The long-winded method of getting going with LDP is to Connect and Bind using those options from the Connection menu and fill in all the boxes.  With the Windows Server 2000 and 2003 versions of LDP if you simply want to connect and bind to a DC in the domain that you are already logged into then you don’t need to both with all that.  You simply select Bind from the Connection menu, leave all the boxes empty and then select OK, as shown below.

Bind Windows Server 2003

That’s it – you are then bound to an in-site DC using your current credentials.  There is no need to use the Connect option, unless you need to target a specific DC or port number.

Windows Server 2008 makes this “bind as currently logged on user ” option explicit by a modification to the Bind dialogue options, as shown below.

Bind as currently logged on user

The behaviour is otherwise the same as the Bind method in earlier versions of LDP.

SID Lookup

With LDP you can lookup an object in the directory based on its security identifier (also known as the objectSid attribute).  The method for doing this is convoluted and involves specifying the SID value as the search base using a special syntax in the form <SID=<objectSid>>, e.g. <SID=S-1-5-21-2596592837-3109173549-302247358-1116>.  For this to work the search scope needs to be set to Base, as shown below.

SID Lookup Windows Server 2003

Windows Server 2008 makes the whole process of SID lookup much easier.  You can still use the method shown above, but there is now also a separate SID Lookup option within the Utilities menu.  This is much quicker if you simply need to resolve the SID to the friendly name.  The screenshot below shows the new feature.

SID Lookup Windows Server 2008

ACL Editor

The version of LDP included with Windows Server 2008 delivers the ability to edit object security descriptors (see screenshot below).  Previous versions of LDP allowed you to view but not edit DACLs and SACLs.

acl editor

Help Documentation

In earlier versions of LDP help comes in the form of a 13.3MB file by the name of LDP.DOC.  While the information in the file is comprehensive and useful, very few people knew of its existence.  The documentation for the Windows Server 2008 version of LDP is now fully integrated into Windows Help and Support.


There may well be other improvements within the utility that I am not aware of.  If you’re not already familiar with LDP I recommend you take the time get to know it.  It seems that Microsoft is committed to maintaining the tool and extending its capabilities.


I encounter a fair number of AD implementations as part of my work.  Some are good, some bad and some just plain ugly.  Here’s a more or less random collection of bad habits that I see quite regularly and some tips on how to avoid and/or kick them.

1.  Poor or missing Active Directory monitoring

A number of organisations rely on monitoring Domain Controllers simply as servers.  They will monitor things such as CPU, memory, disk utilisation, disk space, etc., but not AD as a service.  If something goes bad within AD it might not be picked up by standard server monitoring and alerting. You need to ensure that all AD services are available and healthy.  This involves monitoring items such as LDAP and GC port availability and response times, forest synchronisation with an authoritative time source, correctly published DNS SRV records, replication working, SYSVOL healthy, etc.

Implementing a monitoring and alerting solution for your AD service will allow problems to be detected and resolved early, rather than firefighting after the event has happened.

In addition to Microsoft’s Operations Manager Management Pack for AD, there are a number of 3rd party AD monitoring solutions.  NetPro’s DirectoryAnalyzer is one of the more comprehensive.

2.  Bad delegation

AD offers the ability to implement a granular delegation to suit environments of all sizes.  Why is it then that so many organisations end up with little or no delegation and security model?  For example, I regularly see environments that have 20 or more accounts in the Domain Admins group.  This appears to be because it is seen as too difficult and/or time consuming to configure the appropriate delegation.  Once an account is put into a privileged group there appears to be reluctance to remove it “in case it breaks something”.  Here are some general tips around delegation.

  • Document your delegation model.  Implement it, enforce it and monitor it.
  • Separate standard user accounts from administrative accounts.  Only allow administrative accounts to be members of privileged groups.
  • Don’t allow service accounts to be members of the highly privileged groups (e.g. Domain Admins, Schema Admins, Enterprise Admins and built-in Administrators).  If the documentation from a vendor says that this membership is required the information is probably wrong.  99% of the time there is a way to delegate without making the account a member of a privileged group.
  • Apply the principle of least privilege.  Give accounts the permissions they need to perform their tasks and no more.
  • Keep the Schema Admins and Enterprise Admins groups empty.  Only populate these groups temporarily when required for a specific task.
  • Don’t mess with the built-in Administrators group.  Leave it alone.
  • Keep the membership of Domain Admins to a low number (should be no more than 5 trusted individuals, even in large environments).

3.  Abuse of the Default Domain Policy

I have seen a number of environments in which the Default Domain Policy and the Default Domain Controllers Policy are heavily used.  It is considered a best practice to leave the Default Domain Policy and the Default Domain Controllers Policy untouched and to create new GPOs linked at the Domain and Domain Controllers OU to hold your required settings.  The reason for this is that if the Default policies become corrupt and you have no good backups you at least have the option of restoring the defaults using DCGPOFIX.

4.  No formal object lifecycle management

I often encounter environments that have little or no formal process for AD object provisioning, re-provisioning and deprovisioning.  Amongst other issues, this can lead to a large number of inactive/unused accounts and other objects in the directory. Often the problem is only addressed during a migration or upgrade.  The clean-up can be time-consuming, difficult and expensive.  Try to associate each newly provisioned object with a human owner (guardian).  This will help when making changes in your environment and when you need to remove inactive or unused objects from your directory.

5.  No representative staging environment

When making changes to your AD environment, especially schema changes, it is important to have a representative staging environment.  This will reduce the overall risk when making the change in your production environment.  To make the environment representative, try to make sure at least the following items are the same in both environments:

  • Schema extensions
  • Domain Controller service pack and patch levels
  • Domain and forest functional levels
  • Number of domains
  • GC availability
  • FSMO role distribution

6.  No tracking of schema changes 

There is nothing built-in to AD that will keep track of what changes have been made to the default schema.  Quite often I see environments in which the administrators have no idea what changes have been made to the schema.  This can lead to risk and uncertainty when making future changes.  If you have a formal change management system in place in your organisation, ensure that schema changes are included and fully documented.  Try to maintain copies of the LDIF files that are used for the schema extensions,  These are useful for preparing test environments as well as being self-documenting. 

Even if you do have a formal change management system in place, consider keeping a separate change log somewhere inside your AD environment (e.g. in SYSVOL).  Change management systems may come and go, but your AD infrastructure could be in place for 20 years or more.

7.  Missing forest recovery plan

Given the importance of AD to most organisations, I am constantly amazed at how many have no forest recovery plan.  When challenged on this, most just point to off-site DCs as an indication of the redundancy they have.  But what if you lose forest-wide functionality?  Microsoft’s excellent whitepaper on forest recovery lists the following failure/horror scenarios that might require a forest recovery:

  • None of the domain controllers can replicate with its replication partner.
  • Changes cannot be made to Active Directory at any domain controller.
  • New domain controllers cannot be installed in any domain.
  • All domain controllers have been logically corrupted or physically damaged to a point that business continuity is impossible (for instance, all business applications that depend on Active Directory are non-functional).
  • A rogue administrator has compromised the Active Directory environment.
  • An adversary intentionally or an administrator accidentally runs a script that spreads data corruption across the Active Directory forest.
  • An adversary intentionally or an administrator accidentally extends the Active Directory schema with malicious or conflicting changes.

The whitepaper offers guidelines for building your own forest recovery plan and provides a sample roadmap for the recovery steps involved.  Microsoft also recommends that you test your forest recovery at least once per year.

8.  Missing subnet registrations

In a number of environments I have seen, AD subnets are registered and associated with their corresponding AD site when the infrastructure is first put in place.  Subnets introduced afterwards are not always registered.  When subnets are not registered, clients on those subnets will not find an in-site DC and/or GC to use, which can lead to slow responses and unnecessary bandwidth utilisation.

DCs detect connections from clients on unregistered subnets and log the information in the Directory Service event log (Event 5807). The DC also commits the information into the %windir%\debug\netlogon.log.  You should regularly monitor your DCs for missing subnets and register them as required.

9.  No auditing of Directory Service Access events

If someone deletes an entire OU tree in your domain, you are very likely going to want to know who (or at least which account) was used to perform the deletion.  That information will be captured in the security event log of the DC where the change was made, as long as auditing is enabled for the DCs via Group Policy and turned on in the appropriate SACLs of the objects within the directory.  Quite often I see that either one or both of these two steps are missing.

I recommend defining and documenting an audit policy for your AD environment and then implementing the policy.  Each environment will have different auditing requirements based on the type of organisation that it is, so it is important not to simply accept the default configuration.

10. No event log consolidation

This is linked to the previous entry.  There is no point implementing an audit policy if you then subsequently lose the information you need simply because the events have been overwritten in the security event log.  Microsoft doesn’t provide a built-in mechanism for consolidation of audit and other event log information.  They do however include an Audit Collection System as part of Operations Manager.  A number of 3rd parties offer similar solutions that provide a centralised, consolidated view of event information.  These systems have the advantage of storing the events more efficiently for much longer periods of time and allowing faster event searches.  If the information is important to you (as it is for most organisations) then consider putting the money and resources aside to implement such a system.


It’s been a little while since I’ve blogged, so here’s a more or less random collection of snippets for you to enjoy/delete at leisure.

Quest acquires Netpro

Wow, this one took me by surprise, especially as I have been contracting to Quest on and off for the past 10 months.  Two of the biggest names in the Active Directory management space are now one.  It’s going to take quite a while for competitors to breach the gap.

Microsoft acquires Deano

I just learned from Joe Richard’s blog that Dean Wells has taken a position at Microsoft within the Directory Services product team in Redmond.  I’ve known Dean for the past six years or so and he is one of the most knowledgeable AD people around.  He’s forgotten more about AD than most of us know.  I’m sure he’ll be a huge asset to the DS team.  Good luck Deano!

Handy CSV import script

I came across a good vbscript for modifying AD attribute values using a CSV input file.  There are a number of methods and scripts around that can work with CSV input files, but the cool thing about this script is that can easily be modified to accommodate different attributes.  Check it out here.  I’m thinking of putting together a Powershell version of the same thing.

Good anecdote from Don Hacherl

A while back I blogged about one of the new features of AD in Windows Server 2008: protection from accidental deletion.  If you were looking for a good supporting anecdote to hasten the deployment of this feature in your environment, look no further than this nugget from one of the Godfathers of AD, Don Hacherl, posted on the mailing list at ActiveDir.org:

From: ActiveDir-owner@mail.activedir.org [mailto:ActiveDir-owner@mail.activedir.org] On Behalf Of Don Hacherl
Sent: Sunday, 7 September 2008 4:52 p.m.
To: ActiveDir@mail.activedir.org
Subject: RE: [ActiveDir] Delegating Start/Stop Service on DCs

Years ago I worked with a “domain admin qualified” person at Microsoft who fat fingered the admin UI and deleted a container instead of the object he was intending.  The container was named “North America”, and that was the night we wrote our first authoritative restore tool.  (Later he said “I wondered why it was taking so long to finish.”)

A tightly constrained proxy program can be more reliable and less dangerous than a distracted human administrator.



My sessions at Auckland and Sydney completed without mishap and my demos (bizarrely) worked without one single blue-screen :-)   The feedback was positive and I was happy with the eval scores.  Looking at the video of my session, I realise that I need to slow down a little, engage the audience more and stop saying “um” so much.  Talking in front of a large audience is nerve-wracking and I wasn’t even aware I was doing it.

Tech-Ed in Sydney was also a good opportunity to catch up with fellow DS MVP Gil Kirkpatrick and my ex-colleagues from Gen-i, Craig Pringle and James Brombergs.