I have an Exchange 2010 on premises organization with about 80 mailboxes. I'm planning to migrate half of these mailboxes deeemed "mission critical" to O365, and leave half of them on premises. I'd like to perform this as a cutover migration, and
at the same time, rename the on premises domain something like "@corp.contoso.com", with the O365 mailboxes continuing to use simply "@contoso.com" (which is our existing domain). What are the basic steps to accomplish this? I can complete
the cutover migration, which will grab all mailboxes, but then I expect I'll just add the domain as an accepted domain in the on prem server, change the recipient policies to use the new domain name as default and apply to all local mailboxes, update mx/autodiscover
records for new domain. Is that about it?
All users physically on the same LAN as this exchange server and in the same AD domain will be looking to O365 for their mailboxes, and all remote users will be looking to the on-prem server for theirs. What is necessary to make this work correctly? Just change the autodiscoverinternaluri record to point to o365?