My company is currently using Microsoft Exchange Server 2007 and wants to upgrade to 2010. My company has about 100 employees and a large flow of email messages in every hour.
Read from Microsoft article (http://technet.microsoft.com/en-us/library/dd638158.aspx), an extra domain is required for the co-existence when both servers are running.
As creating an extra domain is complicated, is there any quicker method that does not require an extra domain?