Exchange Online - does it need AD?

Question

Active Directory

Now we use mail from Yandex, we would like to go to our mail and deploy our Exchange server. We learned that there is an Online version. Active Directory DC is not deployed. Questions:
1) In order to deploy Exchange Online - is it necessary to have AD?
2) If so, with which version of AD can you interact with Exchange Online - local or cloud?
3) For the cloud version of AD and Exchange - is it also necessary to purchase separate access licenses (CAL)?

Answer 1

Hey!
1. No, there is no need for a local AD.
2. Both cloud and local.
3. CALs are necessary for normal AD. If you only have Azure AD, then classic CALs are not needed. But you need certain licenses associated with either Azure or Office 365. I
recommend that you read:
https://docs.microsoft.com/en-us/office365/enterpr...
https://docs.microsoft.com/en -us/azure/active-dire...
When linking ground AD+Exchange Online (Office 365), Azure AD acts as an intermediary.
All this is synchronized via Microsoft Azure Active Directory Connect
As always, everything is individual and depends on your environment. In short - if you have few users, say up to 50, then for now you will only need Exchange Online. If it's bigger or if it's going to grow quickly, I'd consider deploying my own directory service (AD). Local or cloud, again, you decide, starting from your tasks.
If there are further questions, please ask. I've messed around with this enough.