Hello All,
Below is the Customer's messaging environment:
Company-A is already running with on-prem Exchange 2016 with hybrid configurations.
Company-B is running with purely on-prem Exchange 2016.
Now Company-B is acquired by Company-A.
Current status of Company-A Hybrid Configuration: Company-B domain verified and added as accepted domain in Company-A O365 portal.
Also Mail flow for Company-A and Company-B MX records pointed to ProofPoint Gateway for all the inbound and outbound mail flow.
Company-B will be going to decommission post movement of all the on-prem mailboxes to Company-A O365 EXO.
Hence we selected to migration type is Mailbox export to PST, upload PST into Azure Blob storage container, Mapping the PST file and Import PST into O365 mailbox. All the AD accounts will be create in Company-A local AD and sync to Azure AD via AD connect.
Current Stage and Future stage:
Current SMTP address in Company-B: email address removed for privacy reasons as primary address
Post migrating to Company-A domain: email address removed for privacy reasons as primary address and email address removed for privacy reasons as secondary address.
We will be going to create a contact for Company-A and will keep it on Company-A mailbox, so that Company-A emails forwarded to Company-B mailbox.
We will be going to keep the on-prem mailbox as it is but we will block the Exchange protocols for migrated mailbox.
In this scenario we will be having Domain-A and DOmain-B email addresses as email address removed for privacy reasons as primary address and email address removed for privacy reasons as secondary address-Post migrating to Company-A O365 EXO.
Additionally we will be having on-prem mailbox as email address removed for privacy reasons as primary address
This will be applicable for all the mailboxes, resource mailboxes, Distribution Groups as well.
MY CONCERN: When someone from the internet sends email to email address removed for privacy reasons does it sends directly to Company-B on-prem Exchange or does it send that email directly to O365 mailbox.
Any help really appreciated.
Anand Sunka
