Single-label Domain Names and Exchange Server 2007 SP1


EDIT 9/22/2008: The support policy for installing Exchange Server 2007 in an SLD environment has changed, and is now supported. Please go here and read it for follow-up on this situation.

If you attempt to install Exchange 2007 SP1 into an Active Directory forest containing a single-label domain name (e.g. "Contoso" instead of "Contoso.com"), you'll get this error message:

Microsoft Exchange Server 2007 setup cannot continue because this computer belongs to a domain that has a single-labeled DNS name. DNS domain name: XYZ

As the Exchange 2007 SP1 release notes state:

"Exchange 2007 is not supported in environments that use single-label DNS names. Single-label DNS names are DNS names that do not contain a suffix such as .com, .corp, .net, or .org. Exchange 2007 SP1 Setup performs a prerequisite check and will not continue if your environment includes single-label DNS names. For more information about single-label DNS names, see Microsoft Knowledge Base article 300684, Information about configuring Windows for domains with single-label DNS names".

The prerequisite checks built into Exchange 2007 SP1 setup look for this condition and, if found, Setup blocks the installation with the aforementioned error.

While the RTM version of Exchange 2007 also does not support single-label domains, the RTM version of Setup did not block installation into environments containing single-label domain names. With Exchange 2007 SP1, Setup does block installation into a single-label domain. This prereq check is an example of us increasing the amount of things that are checked prior to installations in order to prevent customers from getting into unsupported scenarios. You can expect this trend to continue.

An unintended side effect of the SP1 single-label domain check is that if you installed Exchange 2007 RTM into a single-label domain you are now unable to upgrade to Exchange 2007 SP1. Additionally, attempting to rename your Exchange 2007 domain is not an option because Exchange 2007 does not support domain rename. For some details as to why domain rename is not supported, see the Microsoft Exchange System Attendant service does not start on a computer that is running Exchange Server 2007 after you rename a Windows Server 2003 domain.

What We're Doing about this?

We realize that the new SP1 single-label domain prereq is blocking upgrades. We're actively investigating any issues associated with installing Exchange 2007 SP1 into a single-label domain to see if anything can be done about them. We'll update you on our findings and recommended courses of action on this blog when our investigation is complete. You can expect to hear back from us by February 15, 2008 on this blog.

We also ask that you tell us a little about your environment, if you have a single-label domain and are blocked in your upgrade to Exchange 2007 SP1:

  1. How many domains do you have?
  2. Is the single-label domain a root domain or a child domain?
  3. Does your single-label domain already contain Exchange servers? If so, what version of Exchange?
  4. Do you have Exchange 2000 or Exchange 2003 servers installed in your single-label domain?

You can post replies as comments to this blog post, or if you prefer to keep your answers confidential, please send them to edbeck AT microsoft DOT com. Please use "My SLD Topology" for the subject, if possible!

- Ed Beck


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Comments (58)
  1. Ed-

    Does this mean that .lan or .local domains are considered single-label domains since according to the fine print "DNS names that do not contain a suffix such as .com, .corp, .net, .org or companyname are considered to be single-label DNS names."?

  2. Exchange says:

    yyz,

    No, those are just examples. The domain that does not have the "dot" and something behind it is a single-label DNS name domain (SLD). So "contoso" would be a SLD. "Contoso.local" or .int or ."anything" would not.

  3. jc says:

    Hello Ed, thank you for showing us about this blog.  A lot of us have been in the dark about what to do for about a month.  I was told that the only solution was to start over (rename domain and reinstall E2K7).  Obviously, it is something that I want to avoid.  I’m lucky that I have a very small environment, but others have large complex forests to deal with.  Here are the answers to the questions given above.

    1.  We have 1 domain

    2.  It is a forest root domain

    3.  Prior to installing E2K7, the domain has never had any Exchange Servers.  We currenly have one Windows Server 2003 DC.

    4.  See #3.  

    I’m looking forward to hearing from you guys.  A fix for this would make my life a billion times better!

  4. Dave says:

    I’m running a 2003 SLD that I inherited. I’m not ready to make the jump to 2008 yet, but I assume that this will be an issue when I am ready.  I work for a small business. 2 sites, 100 employees….one IT guy.   I’d like to NOT have to create a new domain and migrate all my users, so I probably will not make the upgrade if that will be required.

    1.  one domain

    2.  forest root

    3.  Yes, Ex2003 SP2

    4.  See above

  5. Luke Edson says:

    I have a customer that all what you asked for:

    1. They have one domain

    2. forest root

    3. Yes, Exchange 2003 SP2 Active/Passive cluster

    4. Yes, Exchange 2007 CCR cluster with two Hub/CAS servers (4 additional servers)

    I have everything working correctly, but I’m glad I read this before attempting to upgrade them to SP1, that would’ve driven me crazy. – Eagerly waiting your workaround.

  6. Ed Beck says:

    Dave – when you say that you are "not ready to make the jump to 2008" are you referring to Windows Server 2008 or did you mean Exchange Server 2007?

  7. David says:

    "This prereq check is an example of us increasing the amount of things that are checked prior to installations in order to prevent customers from getting into unsupported scenarios."

    LOL that’s funny!! just thought I’d repost it…..  Hilarious…

    Ed, you must be a manager!

  8. Matt says:

    1.) 1 Domain

    2.) Root Domain

    3.) Yes, Exchange 2007 RTM

    4.) No, Exchange 2003 Server was removed.

    Thank you for looking into a resolution for this problem.

  9. Lukas Beeler says:

    Why would anyone use a single label domain für Active Directory? That’s just insane.

    I usually use ad.company.tld or ad.company.internal, depending on a variety of factors…

  10. Eric says:

    WOW!! thank you for recognizing this as a problem and trying to help us out.

    To Lukas Beeler: This domain was in place before I got here. Now I have to find a way to make it work.

    1.  We have 1 domain

    2.  It is a forest root domain

    3.  Prior to installing E2K7, the domain has never had any Exchange Servers.  We currenly have one Windows Server 2003 DC.

    4.  See #3.

  11. michal says:

    1) One domain

    2) Root domain

    3) Exchange 2007

    4) No

    Good luck.

  12. Mike Crowley says:

    Please read here: http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=2496277&SiteID=17

    if you haven’t already.  There are several people posting on this issue, including myself.

    I have a client who has 50+ users in an SLD enviroment.  We are using exchange 2k7 with all roles on a single server.  they had exchange 2003 and we upgraded.  I would REALLY love to see this addressed in some sort of workaround.  I am very excited to see this post, and would like to think its because of the above technet post!

  13. Mike Crowley says:

    Sorry, to more directly answer your questions:

    1) One domain

    2) Root domain

    3) Exchange 2007

    4) Did, not anymore

  14. jc says:

    Yes, I think Mike is right.  I know I’ve been checking my inbox for updates on that thread since it came out!  

  15. Tony Bunce says:

      1.  We have one domain.

      2. It is a root domain

      3. It only has the one Exchange 2007 server.  We have no problems running exchange in the domain.

      4. We don’t have any other exchange servers, but we did run Exchange 2003 in that domain without any problems before we upgraded to 2007.

  16. EdBeck says:

    Mike and JC, thanks for pointing out the forum, I have been keeping an eye on that post.  Have a look at the post for the 18th at 12:37 AM.

  17. Dave says:

    Ed Beck:  Sorry, I blew that answer.  I meant Ex.2007, but I had always planned to wait on the Exchange 2007 upgrade until Server 2008 was out and I could install on that.  

  18. Devon says:

    1) one domain

    2) Root domain

    3) We have 6 Exchange 2007 servers and 4 Exchange 2003 servers

    4) We are running Ex2007 and Ex2003

    To Lukas Beeler:

    I think most administrators here are well aware of how "insane" single label domains are.  In our case, this was inherited from the previous IT group (all of which are currently locked up in the asylum).  We would like to fix this but there is not a satisfactory way of renaming the domain once Exchange is installed in the forest.  Thanks for the input though.  ;-)

  19. Devon says:

    1) one domain

    2) Root domain

    3) We have 6 Exchange 2007 servers and 4 Exchange 2003 servers

    4) We are running Ex2007 and Ex2003

    To Lukas Beeler:

    I think most administrators here are well aware of how "insane" single label domains are.  In our case, this was inherited from the previous IT group (all of which are currently locked up in the asylum).  We would like to fix this but there is not a satisfactory way of renaming the domain once Exchange is installed in the forest.  Thanks for the input though.  ;-)

  20. terry says:

    1) One domain

    2) Root domain

    3) Exchange 2007

    4) No

  21. Robert says:

    1. One domain

    2. Root Domain

    3. Yes, 2007

    4. Not any longer, migrated from 2003 last year

  22. Bijleai says:

    1 Domain

    Root Domain

    Yes, Exchange 2000 & 2007

    Exchange 2000 installed in our single-labeled domain.

  23. Benoit says:

    1. Two domains

    2. the both are Root domain

    3. Yes each domain has 1 exchange 2003 server

    4. 2 exhcnage 2003

  24. Thomas Wallutis says:

    Hi,

    now you tell me about this;-)

    The situation at our customer is:

    – one domain

    – Windows 2000

    – Exchange 2000

    – only seven users

    I wanted to make the move directly to Exchange 2007 SP1 and ran into this problem. Now i have installed a complete new forest.

    But there is another nice problem:

    i wanted to use ADMT to transfer users and computers, but ADMT couldnt find the DCs of the old domain. I tried NDS forwarding, zone transfer, WINS replication and LMHOSTS (with 1b and 1c entries); nothing helped. The only thing that helped was to add the "old" DCs with their incorrect FQDN into the HOSTS file on the machine with ADMT installed.

    Greetings from germany

    Thomas

  25. josemtba says:

    1. 5 domains

    2. Root domain

    3. No, exchange 2003 sp2

    4. No

  26. Mike Crowley says:

    Aha, right.  Thanks Ed, I saw your post, just didn’t put two and two together.

  27. Sandro Pizzingrilli says:

    Hi,

    1.  6 domains

    2.  Root domain

    3.  Exchange 2007 RTM

    4.  No more. Upgraded Exchange 2000 to 2007 RTM

    It would be nice to have a solution how to rename a 2003 SLD forest with exchange 2007.

    Regards

    Sandro

  28. Ken says:

    Created Domain as per business senario (not my choice to go single label domain)

    1. 2 domains

    2. Root domain

    3. Running Exchange 2003 and 2007 RTM

    4. Both are in the SLD.

    We haven’t moved any users to Exchange 2007. Did not see the warning about sld installs and was told there were no concerns at MS- Exchange course 5047.

    I’ll be one of many watching this blog.

    Looking forward to some good news.

    Cheers,

    Ken

  29. Rhys says:

    Thank the lord this is being looked at. I was facing having to explain to the top brass why we may have to stay with Exch 2003 for the rest of time. Way too many problems involved with migrating our users and custom apps to a brand new domain. Details below.

    1. 1 Domain, 4 sites

    2. Root domain

    3. Yes, Running Exchange 2003 and 2007

    4. Yep, Exchange 2003

    Also have a seperate company we look after that are running below config.

    1. 1 Domain

    2. Root domain

    3. Yes, Running Exchange 2003 and 2003

    4. Yep, Exchange 2000 and 2003

    Cheers guys.

  30. Vince says:

    I had a support call with MS about this and received much the same answer as we see here.

    1. One domian, 4 sites.

    2. Root (forest)

    3. Migrating to 2007 from 2003. Both currently installed (2003 for public folders).

    4. 2003, 2007 (had 5.5 and 2000).

    have 50+ servers, 200+ computers and most are mobile workers.

  31. Dvityuk says:

    1.One domain

    2. Root

    3. Exchange 2003 SP2 (Upgrade from Exchange 2000)

    4. Exchange 2003 SP2

  32. sam says:

    I thought one of requirements of Windows 2000 AD was that you don’t have Single Labled Domain (SLD). You are always encouraged to use domain "." something.   I am surprised organizations with 200+ users have SLD.

  33. ricargm says:

    1. Almost 200 Domains

    2. Root domain

    3. No. All Exchange servers (2003 and some 5.5) are located in child domains.

    4. No, in fact there are not users accounts nor resources in the single-label root domain.

  34. Less disgruntled customer! says:

    Fantastic, thanks for mentioning this post! Hope you can resolve the issue.

    1) 1

    2) Root

    3) Yes, Exchange 2007

    4) No

  35. fzilz says:

    Really looking forward to a work around or recommended way to resolve this issue.  

    Our network has been in place for 15 yrs, upgrading in place and raising functional level as we went.  The single-label domain name was not an issue when the domain was created (before my time) and until 2003 there was not a rename option.  

    Now we have Exchange 2007 in place and want SP1.  We do still have an Exchange 2003 install for Public folder management and because MS CRM 3.0 connector only runs on 2003 – we expect to remove 2003 when we upgrade to CRM 4.0

    We have a single root domain single forest windows 2003 Multiple DCs.

    We have a remote site with 1 DC and locally we have 6 servers three are virtual. Sharepoint server 2007, SQL 2005

  36. Joao Gazzoni says:

    1. One Domain, w/ 04 DC servers (three W2K and one W2K3).

    2. Root

    3. Four E2K Servers and  two E2K7 Servers;~ 10Kmailboxes.

    4. Exchange 2000

  37. Joao Gazzoni says:

    Changing SLD is a ‘bigger’ infrastructure project.  It is not a messaging project, like the simple upgrade of Exchange.

    And all existing solutions (migrate forest or even a future rename tool w/ E2K7), for a medium-large company,  

    will  be done in a large amount of time (form serval months

    to year).

    The pratic effect is to stop the upgrade from E5.5 or E2K,

    for a ‘dangerous’ period. Because we can not use new anti-spam/antivirus integrated features. And all the new ‘corporate policies’ with Transport Rules. And the new mobile functions. Depending the case and urgency, similar products of other companies will be evaluated to make these funcions.

    Btw:

    IPV6 ist not a good reason for the real world. If it is  incompatibile with SLD, them it is better to block the use of IPV6 on SLD. And not SLD  by SLD itself.

  38. p-r says:

    1 – one

    2- root

    3 – it did, 2003.  Now upgraded to Exchange 2007.  Exchnge 2003 removed.

    4 – not now that we have upgraded

  39. EdBeck says:

    Hello everyone,  

    I just wanted to pop in and thank everyone for their feedback, let you know that I am recording it, and that we’re on track to get back to you with our findings and recommended courses of action by February 15th.

  40. Inf says:

    Came across a help site with a work-around:  www.outlook-web-access.com – first  item.  It says it works in their lab.

  41. jacques says:

    I appreciate you guys looking into the issue.

    Due to time constraints, I may be attempting a resolution, which others may find interesting.

    Ed, I would be interested in seeing what you think of the plan (and correcting me if there’s an issue I don’t see).

    1) Put all Exchange services on manual.

    2) Rename the domain to "current.something"

    3) Install SP1 without launching the Exchange services.

    4) Rename the domain back to "current"

    5) Restart the appropriate Exchange services

    The domain is question is below

    1) 1 Root Forest/Domain – WS2K3 R2 DC’s

    2) Forest is a single-label domain

    3) 1 Exchange 2007

    4) No Exchange 2003

    My direct is J LATOISON at THEHIERARCHY dot NET

  42. Bradley Johnson says:

    Here’s our details…

    1) Single Domain Forest (2k3 R2 DC’s)

    2) Single-label Domain

    3) Exchange 2003 (not for long, only part of mixed mode migration) X1; Exchange 2007 X1 (will be adding Edge Transport down the road)

    We are an MSP, so feel free to contact…

    bjohnson AT ptnet DOT com

  43. inf says:

    SP1 likes to restart things as it goes and will complain

    if you actually disable the services.  Broke many a lab

    machine doing that.

    suggest you try the solution here:

    http://www.outlook-web-access.com

    Especially if you’re just going to rename back after!

    gl

  44. IB says:

    1.) 1 Domain SLD

    2.) Root Domain

    3.) Exchange 2007  

    4.) No, Exchange 2003 Server was removed.

    We have a small enviorment with 4 servers in AD.

    I think the best solution would be to get a domain rename tool that supported 2003 server and Exchange 2007 so we could solve this problem once and for all without having to reinstall all our servers.

  45. T McNutt says:

    One Domain

    Root Domain

    1 2000 exchange w/2007 installed ready for migration

    1 2000 exchange

    Problem: I am ready to retire the 2000 exchange but wanted to patch up the 2007 before I make the switch. Do I wait?

  46. HTRN says:

    I’m with IB, it would be really nice to have a domain rename tool that works with Exchange 2007.

  47. Ade D says:

    Does the inability to rename a domain containing Exchange 2007 only impact changes to the FQDN?  We have a domain on which we need to change the NETBIOS name only, but the FQDN will stay the same (and thankfully isn’t a single label DNS name).  

  48. brad says:

    I have a root domain called "root" and a chile domain called company.local

    EX2K7 Sp1 Installed from scratch on company.local.

    Will I have problems with the root being called "Root" Single-domainname?

    thanks

  49. Stefan says:

    I have one SLDN root domain with 2 AD servers and Exchagen 2007 already installed. What can I do since I can’t install SP1? I really don’t want to migrate the domain.

  50. jc says:

    The big day is here tomorrow!

  51. zembla says:

    Waiting for solution….

  52. Rhys says:

    Waiting with baited breath. Come on fella’s! :-)

  53. Micko says:

    Comeon comeon…

  54. Exchange says:

    Everyone that has been waiting…

    This is coming, hang on for just a little longer!

  55. JoeWells says:

    Well, since there’s a little more time:

      1. One domain

      2. Root

      3. We’re just beginning to install Ex 2007, but it isn’t in production yet.

      4. No previous versions of Exchange.

    Fingers crossed like everyone else.

  56. Exchange says:

    Hi All! Please see the following post:

    http://msexchangeteam.com/archive/2008/02/15/448140.aspx

    Thanks!

  57. Nimish says:

    We have ove 100+ servers and 400 desktosp. It not possible to change the single label domain to FQDN in few months.

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