Office365 DirSync Active Directory Integration

Solution 1:

1) The attributes for provisioning email addresses in O365 are Mail and ProxyAddresses. Populate the ProxyAddresses with SMTP:[email protected] smtp:[email protected] etc

2) I believe you need to populate Mail and ProxyAddresses

3) Not a problem. However, we prefer to add the email domain as a UPN suffix and set the users' UPN to match their email address, for simplicity. (ie. O365 login and email address are same)

As mfinni correctly points out, you can (indeed are advised to) maintain an on-premises exchange server for management. However, no on-premises exchange and DirSync rather than federation is totally supported.

Solution 2:

In my understanding, the current proper method for doing this is to have an Exchange 2010 server onsite. The 0365 account licenses you for a single server instance; this integrates with AD (populating all of the proper Exchange attributes) and then you federate with your O365 instance.

Point 3 is not a problem at all.