Can You Have An Underscore In A Domain Name

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Upgrading AD and Exchange where AD 2003 has Underscore in Name

Question
Hi, we have an older 2003 AD with 2003 exchange system where the domain name
actually has an underscore within the name "domain_name" and if we are
understanding correctly, new 2008 AD domain names cannot have an underscore in
the name. Knowing that we are upgrading exchange as well, all on new servers,
what is the best sequence of events here for the upgrade?
- Set up a new AD
2008 server with a new domain name? upgrade and rename? if so, how do we do
it?
- Exchange upgrade? Do this after the rename of the domain name?
- can
we leave the underscore in the domain name?

Hope this won't become a
nightmare....

John

Answers

- Marked as answer by Friday, April 27, 2012 9:10 AM
Hi,

You are correct, you cannot have an underscore in Active Directory DNS domain name. I would suggest to setup new 2008 AD domain in a new forest and migrate the old forest stuff.

Also Check the ADMT high level steps by Santosh:
http://www.sivarajan.com/admt.html

ADMT v3.2 is now available:
http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=20C0DB45-DB16-4D10-99F2-539B7277CCDB

ADMT doesn't have an Exchange/mailbox migration option. It has only option to export the mailboxes and import them. But you will have some mail routing challenges here – like non-migrated users sending emails to migrated users and vice versa.

If you have a lot of mailboxes to migrate, I would suggest to use third party migration tool Quest or NetIQ or a custom solution for mail routing (you can use a dummy SMTP address in the targetAddress attribute and a SMTP connector during the migration/co-existence to achieve this).

Best Regards,

Abhijit Waikar.
MCSA 2003 | MCSA:Messaging | MCTS | MCITP:Server Administrator | Microsoft Community Contributor | My Blog

Disclaimer: This posting is provided "AS IS" with no warranties or guarantees , and confers no rights.
- Marked as answer by Miya Yao Friday, April 27, 2012 9:09 AM
You can't install Exchange 2010 with underscore ( _ ) character in the domain name. Also, if you are running Exchange 2007 and above or CA services, you can't rename a domain. Migration using migration tool is viable option considering the issues seen post renaming a domain. Since, exchange 2010 can't be introuced without removing a underscore in the domain name, you have to opt for the option carefully.

Exchange 2010 setup process fails if you try to install Exchange Server 2010 into a domain that has an underscore character ( _ ) in the domain name http://support.microsoft.com/kb/975104

Domain rename is pretty tricky and risk as well and i guess instead of risking whole domain with renaming operation you would be more happy to take safer approach of migration using ADMT or quest tool.

Renaming a Domain: Process and Side Effects http://support.microsoft.com/kb/178009

More references on the domain rename

http://technet.microsoft.com/en-us/library/cc794869%28v=ws.10%29.aspx

http://www.techrepublic.com/forum/discussions/102-229757

If you plan to take a migration approach, take a look at below article. http://awinish.wordpress.com/tag/admt/

Awinish Vishwakarma - MVP - Directory Services
My Blog: awinish.wordpress.com Disclaimer This posting is provided AS-IS with no warranties/guarantees and confers no rights.
- Edited by Awinish Tuesday, April 24, 2012 5:57 AM
- Marked as answer by Miya Yao Friday, April 27, 2012 9:10 AM

Can You Have An Underscore In A Domain Name

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