That is the question and the answer is: It depends, but most like yes. You need to ensure that you have no on premises dependencies. I’ve had this conversation with more than 5 customers in the past 2 weeks, so thought I’d present the discussion of the options and thought process around removing the Exchange servers from on premises.
This tech net article lists the options and discussions, but here is the short and skinny:
- Have you migrated your provisioning and de-provisioning processes to the cloud?
- Are there any dependent applications or devices performing SMTP mail relay?
- Are there any other dependencies?
For question 1, many customers have not reviewed or updated their provisioning process. Mainly, the scripts or directions have just added a mailbox migration into the mix, but have not looked into: just creating the AD account onsite, kicking off AAD sync, then licensing the provisioned account in O365. If you leverage group membership licensing, that makes this process even easier.
For the second question, usually customers have several or even hundreds of scanners or all in one devices that can send messages via SMTP and therefore need updating. This updating of the devices could be a very manual process and one that could take a long time. However, I have found several customers with 3rd party appliances or other SMTP servers that already exist in their environment and can be used instead of the Exchange Servers.
And yes, you can point the devices directly to the cloud. You must make sure they have internet access (which they may or may not) and update the SMTP value on each device.
That covers most of the concerns, however, in item #3, there could be other applications, or processes, or something in the environment, somewhere, that still needs either a mailbox on premises, or maybe a public folder for access, but something that Exchange needs to provide. Thus, the dependency would need to be reconfigured.
If you do come to the understanding that you no longer need Exchange Servers on site, the steps for decommissioning them are found here. Or if realize that you need to retain Exchange servers on site, there is a free hybrid license option available, if you only need SMTP relay. You cannot host a mailbox database, nor any mailboxes on those servers with a hybrid license, but it could be an option for many customers.
There you go, a nice and quick discussion about to stay hybrid or not to stay hybrid.