I have 2008 Domain environment consists of the following :-
Exchange 2010 SP3 + DAG.
SQL Server 2012 + Cluster.
Oracle 11g integrated with A.D.
another 24 services ( home made ) integrated with A.D based on Asp.net & PHP & Drupal and Java for authentication.
my current domain is xyz.com we must change it to ABC.com also that will reflect to Exchange for sending and receiving .
for Exchange a new accepted domain and email address policy enough ?
can i use UPN suffix to keep the existing domain and make all users authenticate using UPN also the new users take the UPN ?
can i use upn suffix for domain join ?