We are doing a migration from Exchange 2003 to Exchange 2010 the organization has approximately 6,000 mailboxes When Setup starts the Exchange CAS, presented the following problem: Error: The DNS domain name is invalid. It contains characters other than 'A'-'Z', 'a'-'z', '0'-'9', '.' and '-'. Domain Name: client_pr.br Is there some solution to this problem other than is renaming the domain?

Yes, there is one: create another domain tree in your existing forest and install Exchange there. "If the invalid characters are in the organization's DNS domain name, consider the feasibility of renaming the DNS domain or installing Exchange 2007 into a new domain tree." From: Invalid Domain Name System Domain NameJesper Bernle | Blog: http://xchangeserver.wordpress.com

Agree..Since Exchange 2007 special character (I call it ;)) is not allowed. Follow the article provided by Jesper and exchange installation should be fine. Cheers, Gulab | MCTS-MCITP Messaging: 2010 | MCTS-MCITP Messaging: 2007 | MCC 2011 | Skype: Gulab.Mallah

Thanks Jesper I had read about this also, I wanted to escape these two options. But now I need to explain to the client on these two options.

Thanks Gulab