How to migrate users between Active Directory forests using ADMT when the source and target domain names are similar

This content is 19 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

One of my clients is undertaking a domain consolidation process, moving to a new Active Directory (AD) forest called with two child domains – and All of the user accounts from the various NT 4.0 and Windows 2000 domains around the organisation are being migrated into this structure using the Active Directory migration tool (ADMT) but access will be required to resources in the legacy domains (at least in the short term).

This is all reasonably straightforward, or it was until my colleagues unearthed a a new domain in Belgium called Because ADMT is reliant on external (NT 4.0) trust relationships, which are established using NetBIOS names (not DNS), and because already has a Kerberos trust with, it will not allow an external trust to be created with We don’t want to have to recreate the users and so I had to find a way around the problem. It’s not that complex – just a two step migration, but we also needed to confirm that the sIDHistory attribute for each user would remain in place if the account was migrated more than once (in order to maintain access to resources in the original domain).

To prove this, I created four virtual machines (which run very slowly when the host is a notebook PC with only 1Gb of RAM…) representing domain controllers as follows:

  • dc4.transfer.local

I created three users in (imaginatively named user1, user2, and user3) and a share called userdata (with some test files), to which users 1 and 2 had access and user 3 was denied access. I also disabled user2 and created a group to which all three users were added as members.

The intention was to transfer the user accounts from to transfer.local, and then to perform a second migration from transfer.local to, maintaining the account status (enabled or disabled), group membership and passwords, and then using a connection to the files on the share as a test of migrated sIDHistory.

Once I had DNS resolving names across the three forests, I installed ADMT on dc4.transfer.local and migrated the users. ADMT is fairly straightforward to set up and run, but it is necessary to read and fully understand the requirements in Microsoft knowledge base article 326480, with the main points for my client’s scenario being:

  • The target domain needs to be running in Windows 2000 native mode or later (without this, the sIDHistory attribute does not exist).
  • The computer running ADMT must be a member of either the source or the target domain.
  • The source domain must trust the target domain (in order for user and group migration to take place).
  • Administrator rights are required in both the source and target domains (e.g. by adding the target domain’s Administrator account to the source domain’s Administrators group and vice versa).

There is also an (undocumented) requirement that a non-blank password must be used for the account used to run ADMT (because I was running on a dedicated test system I was originally using the Administrator accounts with blank passwords, which needed to be changed). There is also some troubleshooting information available in Microsoft knowledge base article 322970.

Once the above are in place, ADMT will complete some of the other requirements for user and group migration, namely:

  • Creating a new (empty) local group in the source domain named sourcedomainname$$$.
  • Enabling auditing for the success and failure of Audit account management on both domains in the Default Domain Controllers policy.
  • Configuring the source domain to allow RPC access to the SAM by setting HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\LSA\TcpipClientSupport to 1 on the PDC Emulator for the source domain and restarting that server.

Microsoft knowledge base article 326480 also describes the process for installing the password migration DLL in order to migrate user passwords.

It should be noted that the configuration items above expose serious security weaknesses which must be secured once the migration is completed.

Once the users (with passwords) and group (with membership) had been migrated once, I could install ADMT on and migrate them again, this time from transfer.local to

Finally, to test that the sIDHistory attribute was allowing access to resources in the original source domain (, I logged on to and started a command prompt, from which I could issue the following commands:

net use e: \\dc3\userdata /user:emea\user1 password

(i.e. a connection to a resource in the original domain, using an account in the domain, which as expected, allowed access to the share as well as browsing subject to file permissions on the original resources).

net use e: /del
net use e: \\dc3\userdata /user:emea\user2 password

(as expected, access was denied as the account was disabled).

net use e: /del
net use e: \\dc3\userdata /user:emea\user3 password

(as expected, a connection was made, but access was denied when an attempt was made to browse the share due to denying permissions to user3 on resources in the domain).

net use e: /del

All of this indicated a successful migration from to and so I decided to look a bit closer at the sIDHistory attribute which allows all of this to work.

One of my colleagues had alerted me to an article on security concerns for migrations and upgrades to Windows Active Directory, which confirmed that a single user account might have numerous sIDHistory entries, depending on how many domains contained the user name before the migration and consolidation.

After installing the ADSI Edit support tool from the Windows 2000 media I could see that the sIDHistory attribute had two values on the version of the object (shown in the accompanying screenshot), a single value on the transfer.local version of the object and was not present on the original version.

sIDHistory in ADSI Edit

Rather unhelpfully, the ADSI Edit representation of the sIDHistory is not in the usual form, but if the ldp.exe support tool is used, then by connecting to the server, binding as an administrator, and viewing the directory tree, the sIDHistory can be seen in its normal form along with the objectSID. As expected the objectSID for (S-15-78B99911-320A1743-74B49FF8-451) appeared as the sIDHistory attribute for user1@transfer.local and had two values for sIDHistory – the original objectSID from (carried over in the sIDHistory from user1@transfer.local) and the objectSID from user1@transfer.local (S-15-11DA0ABB-64495118-320A1743-454).

sIDHistory in the LDAP editor

Incidentally, had this method not worked, my colleagues and I had identified two further potential methods of migrating the users and groups which I did not try:

  1. Install a second domain controller in, let it replicate, take the original offline and seize the FSMO roles, then upgrade to Windows Server 2003 and rename the domain, allowing a one-step migration to to to be used. After this, the Windows Server 2003 domain controller could be taken offline and the original Windows 2000 server brought back online (seen as a very complicated solution).
  2. Use the clone principal utility to clone the original accounts in the new domain (workable, but requiring some scripting skills and potentially a lot of time).

After many hours of waiting for virtual machines to catch up with my mouse/keyboard, I don’t think I’ll be trying them just yet…

Some clarity around Microsoft’s operating system release cycles

This content is 19 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

I normally avoid blogging about Microsoft’s release plans for new technology as they tend to be out of date almost as soon as they are written; however, at last week’s Microsoft Technical Roadshow, John Howard gave one of the clearest examples I’ve ever seen of Microsoft’s plans for new operating system releases.

Microsoft aims to provide a major operating system release every four years with release updates approximately half way between major releases. For example, Windows Server 2003 was released on 28 March 2003, Windows Server 2003 R2 is expected during 2005 (delayed due to the late shipping of service pack 1) and the next version of Windows Server (codenamed Longhorn) can be expected in 2007. Following this pattern, we can expect an update to Longhorn in 2009 and the following version of the Windows Server product (codenamed Blackcomb) to make an appearance in 2011.

On the support side, mainstream service packs and updates will be provided for at least 5 years from the date of a major release (i.e. until 2008 for Windows Server 2003) with extended support available for a further 5 years.

No NAP until Longhorn

This content is 19 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

Last year I commented that network access protection (NAP) had slipped from a planned feature pack for ISA Server 2004 to Windows Server 2003 Release 2 (R2). Well, it seems that has changed. Confirming what I wrote last March, when I blogged about the need for network segmentation and remediation, Steve Lamb commented at last week’s Microsoft Technical Roadshow that NAP will be a feature of the next version of Windows Server (codenamed Longhorn) and not in the R2 release scheduled for later this year.

Apparently the reasons for this are that NAP will require kernel mode changes (and there will be no kernel mode changes in R2) and the extra time will allow Microsoft and Cisco to ensure that NAP (Microsoft) and NAC (Cisco) play nicely together.

Until then we will have to make do with the network access quarantine controls (originally part of the Windows Server 2003 resource kit and productionised as part of the release of Windows Server 2003 service pack 1). The main differences are that network access quarantine control allows quarantining of inbound connections via the Windows routing and remote access service, but NAP will will support quarantine for wired and wireless LAN connections too.

How about this for a test system…

This content is 19 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

In one of the SQL Server sessions at last week’s Microsoft Technical Roadshow, Michael Platt showed the first three minutes or so from an MSDN Channel 9 video. In it, we saw one of the systems at Microsoft’s labs in Redmond where ISVs and OEMs assist the SQL Server team with their performance testing and benchmarking – an HP Integrity Superdome system with 64 64-bit Intel Itanium 2 CPUs, 1Tb of RAM and a couple of thousand 18.2Gb disks. Why so many small disks? Apparently it’s about providing provide parallel reading capacity to increase the overall system throughput and hence run the CPUs at their limits.

The whole system cost in the region of $5.1m and the full details of the benchmark tests may be found on the transaction processing performance council website.

Interestingly, one of the problems encountered during the benchmarking was running out of power to spin up all of the disks and having to install a new power distribution unit at a cost of $250,000!

How Microsoft does IT

This content is 19 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

Microsoft IT ShowcaseI was at a presentation last week where some interesting statistics were given about Microsoft’s own IT operations:

  • 300,000 devices for 92,000 users in 89 countries.
  • 7,000,000 remote connections per month.
  • 3,000,000 internal e-mails per day.
  • 100,000 e-mail accounts with 99.99% mailbox availability.
  • 1.7Tb SAP database (running on Microsoft SQL Server).

Now who says that Microsoft software doesn’t scale to enterprise levels? For anyone who has ever wondered how Microsoft runs its own IT, check out the Microsoft IT Showcase.

Crazy ringtones – could skins for smartphones be the next big thing?

This content is 19 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

It had to happen – with music single sales falling and downloads incorporated into the official UK music charts (since 17 April 2005) one day a ringtone-derived music single (the inevitable evolution of a music single-derived ringtone) would outsell a major music act. Keni was outraged to hear the crazy frog ringtone on my phone today (and no, I didn’t buy it – my brother sent it to me via Bluetooth) but I’m amazed at just how much attention the crazy frog has generated, seeing as it all started off as a Swedish student imitating his mate’s two-stroke scooter (hmm… I do something like that with my son in the shopping trolley as we whizz ’round Tesco…).

What seems particularly strange is how people are petitioning to get this off our airwaves (even complaining to the UK advertising standards agency) – surely if a company has enough money to pay for this level of advertising (and if you’re going to make £10m from selling a single ringtone, that should be plenty), then let them do it – even the “no advertising here” BBC runs ads on its World Service and in the RHS Chelsea Flower Show coverage Alan Titchmarsh regularly mentions that the event is “supported by Merrill Lynch” (there goes the last of my street cred’).

The ringtone download market is growing at a phenomenal rate and according to The Independent, the typical £3 cost of a realtone is divided up as follows:

  • Music publishers 32p.
  • Content aggregators and distributors 64p.
  • Mobile operators 75p.
  • Record labels £1.29.

I was interested to hear Keni comment today that with the launch of the Windows Mobile 5.0 platform (formerly codenamed Magneto), the market for skins to customise smartphones could potentially be as large as the ringtone market (especially with the convergence of consumer-focused mobile phones and digital music players). We’ll have to see if that prediction comes true, but in the meantime I have to confess that I quite like the crazy frog… and the Nokia tune has been driving me mad for the last ten years.

How to take part in some time travel

This content is 19 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

So you thought that old version of your website was gone forever? It may have been a little naive of me, but I figured that once I put up a new version of my website, then that was it, the old one was overwritten.

Not so, it seems – today I stumbled across the Internet archive wayback machine, which is a service that allows people to enter a URL, select a date range, and then surf on an archived version of the website. Scarily, I was able to search on old versions of my website going back several years. Not everything is in there, it takes a while to load, many graphics are missing, and if a site wasn’t picked up by the Internet archive crawler then it just won’t appear, but how about seeing old versions of

I guess this can be useful. For example, I used to work for a company called ICL. That name is long since consigned to the history books (they are now trading as Fujitsu Services), but it is still available on the wayback machine. I managed to find a press release from back when the BBC and ICL jointly announced BBC Online in September 1996; as well as what ICL was saying about millennium date compliance in the middle of 1997.

Most web administrators will know that they can control web crawlers (like the one behind the Internet archive) using a robots.txt file in the root of the site (there is even an online robots.txt generator). After the robots.txt file is loaded in the root of the webserver, the wayback machine can be forced to crawl the site, pick up the new file, and remove all documents.

Now it seems I need to go and update the robots.txt files on my websites…

Anyone worried about running Microsoft ISA Server as a firewall?

This content is 19 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

Over the last few years just about every network administrator I’ve worked with has laughed at the idea of a Microsoft firewall in an enterprise environment (at least as a front line of defence – many organisations use Microsoft ISA Server behind another firewall). When forced by the American parent company to run Check Point FireWall-1 on a Windows platform instead of a Nokia appliance server, one of my ex-colleagues in the European subsidiary of a major fashion design, marketing and retail company was disgusted; but in all honesty, a well-patched and well-managed Windows system can just as secure as a well-patched Linux one (and conversely badly patched systems are badly patched, whoever the operating system vendor).

The Common Criteria Evaluation and Certification Scheme (CCS) is an independent third party evaluation and certification service for measuring the trustworthiness of IT security products, recognised by governments in Canada, the United States, United Kingdom, Netherlands, Germany and France.

Windows 2000 Professional, Server, and Advanced Server with service pack 3 and the hotfix described in Microsoft knowledge base article 326886 has been certified for common criteria evaluation assurance level (EAL) 4+; and ISA Server 2000 with service pack 1 and feature pack 1 (in firewall mode) has EAL 2 certification. According to Microsoft, Windows XP with service pack 2, Windows Server 2003 with service pack 1 and ISA Server 2004 are all undergoing EAL 4+ certification at present.

In addition, ICSA Labs tests firewall products against a standard yet evolving set of criteria and Microsoft ISA Server 2000 with service pack 1 running on Windows server 2000 with service pack 4 has been certified by ICSA. As a side note, for anyone looking at the area of firewalls, the ICSA firewall buyer’s guide is worth a read.

So it seems that a Windows server can be secure enough to run a firewall; and that Microsoft’s firewall product is also pretty secure. EAL 2 might not be the highest certification level, but if ISA Server 2004 achieves EAL 4+, then maybe all of those network administrators’ minds can be put to rest.

Things to ask your ISP before you sign up

This content is 19 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

A couple of days back, I came across a forum post on things to ask your ISP before you sign up – looks like some good advice to me.

Whatever the platform, it’s the solution that counts (problems with AOL on a Mac via ADSL)

This content is 19 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

At the danger of being flamed by Apple Macintosh fans everywhere (please don’t) – I thought Macs were supposed to be simple.

To be honest, that’s one of the reasons I didn’t get on with my iMac in the late 90s – it was too big a shift for me as a long-time Windows user (even though I had used Macs at uni’ many years before), but that was with OS 8 or 9 (I can’t remember) and I guess, being UNIX based, that OS X will also give me a command prompt?

Anyway, a couple of nights back, my neighbour, who is very proud of his new purchase – an iMac G5 – dropped by to ask if I could help him get his Mac connected to the Internet. His Windows PC connects fine, using a BT Voyager 100 ADSL modem and AOL but when he called AOL, they said they don’t provide Macintosh support. We spent a few hours looking at this and the best advice I could find was to obtain the Mac drivers for the modem and some configuration information (as well as a phone number for AOL Mac support!) from the Mac User’s forum. Unfortunately the last post at the time of writing is just a few days old and is from someone who had a working connection that has just stopped and we couldn’t get it working either.

Fast forward a couple of days and my neighbour dropped by to say that he phoned AOL and they only support dial-up connections for Macintosh users. He also found the same anecdotal evidence I had found of people who have their Macs working with AOL broadband (but not consistently). Once glimmer of hope is that net4nowt and MacUser talk about AOL Services for Macintosh, which it seems was released on 6 May 2005 as AOL Service Assistant, allowing Macintosh users to access AOL services, although the net4nowt advice seems to be to use this on a routed connection (not direct via ADSL modem).

My neighbour is now off to buy a broadband router (probably the best solution for him anyway given that he has multiple computers now) – fingers crossed that gets him on line with the Mac.

The irony of all this is that he upgraded from Windows ME to XP and couldn’t get his broadband connection working – until I downloaded the BT voyager 100 drivers for Windows XP for him a couple of weeks back! Now his Windows PC works, but the Mac he bought in frustration doesn’t… just goes to show that it doesn’t matter what platform you use, there will usually be some complications in getting the various elements of a solution to pull together (and it seems that for broadband AOL on a Mac it just won’t work at all).