question

HK-7855 avatar image
0 Votes"
HK-7855 asked HK-7855 commented

Exchange hybrid setup question

Hello,

I have two question about exchange hybrid option.
There are classic and modern hybrid option, I found this article is some what useful



But it does not answer all my questions.

Here is my situation, I have on-prem exchange 2019 servers, there are 3 of them and it is clustered (DAG), requirement is setup hybrid only, so that teams can see employees' free busy info and show availability information correctly. We will not utilize office 365 (exchange online) to receive and send external emails.
We will not move any mailboxes to the exchange online. The only reason we want to setup the exchange hybrid is to sync free/busy info for teams.

Q1, I went to an office 365 class and the instructor said only way to make the free/busy info to be synced to exchange online is to perform modern full sync, however it will sync (duplicate) users' mailboxes to exchange online the reason is that when on-prem exchange goes fubar I can immediately use the exchange online, is this true? if it is true how do I prevent it from happening.

Q2, What is the most important difference between classic and modern hybrid?? the technet web site does not really say anything about it.

My question is simply, how do I sync only free busy info to exchange online?

office-exchange-online-itpro
5 |1600 characters needed characters left characters exceeded

Up to 10 attachments (including images) can be used with a maximum of 3.0 MiB each and 30.0 MiB total.

LucasLiu-MSFT avatar image
0 Votes"
LucasLiu-MSFT answered HK-7855 commented

Hi @HyeongWookKim-7855 ,
1.According to the Microsoft’s official article, the users must be synchronized to Azure Active Directory and we need assign Teams license for the Azure active Directory Synced users. According to my test, if the mailbox is not migrated to Exchange Online, the synchronized user will appear in the Admin center of Exchange Online as a "Mail user" type. After that, even if I assign a Microsoft 365 license to it, there will be no duplicate mailboxes in Exchange online and on-premises Exchange at the same time.

2.Compared with fully hybrid deployments, modern hybrid deployments have some constraints. For example, Hybrid Modern Authentication is not supported, and only a single Exchange organization is mixed. In the introduction of the official article, for Teams' Calendaring features that require access to on-premises mailboxes, it's recommended that you leverage the full Classic Exchange Hybrid Topology.
For more information you could refer to: Microsoft Hybrid Agent

3.As I said above, we need to sync the user to Azure Active Direcotory, we couldn’t sync only free /busy to Exchange online. And according to the research on the process, I agree with what Andy said, it is recommended that you perform a classic hybrid deployment. For more information: Configuring Teams calendar access for Exchange on-premises mailboxes



If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.




· 1
5 |1600 characters needed characters left characters exceeded

Up to 10 attachments (including images) can be used with a maximum of 3.0 MiB each and 30.0 MiB total.

I have one more question, my org going to get P1 license will it be sufficient?

0 Votes 0 ·
AndyDavid avatar image
0 Votes"
AndyDavid answered AndyDavid edited

You have to use full Hybrid if you want calendar integration - which I assume you do :)
https://docs.microsoft.com/en-us/microsoftteams/exchange-teams-interact

93127-image.png



image.png (24.5 KiB)
5 |1600 characters needed characters left characters exceeded

Up to 10 attachments (including images) can be used with a maximum of 3.0 MiB each and 30.0 MiB total.