After you complete a new installation of Exchange 2010 or after you add an additional Exchange 2010 server role to an existing Exchange 2010 server, you should complete the post-installation tasks. Because each server role offers several features that you can configure for your organization, make sure that you complete the post-installation tasks for each server role that you install.
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Cheers,
Anderson Patricio
http://www.andersonpatricio.ca
http://www.andersonpatricio.org (Portuguese)
Twitter: @apatricio