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Hybrid Exchange to Exchnage Online

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Thinking of moving from a Hybrid Exchange to Exchange Online only? Are there any drawbacks to moving to only the cloud?

Issue: The organization has been running in a hybrid configuration, and I have all of my mailboxes in Exchange Online. I do not need to manage my users from on-premises and no longer need directory synchronization or password synchronization.

Desired End State of Decommission Exchange Servers

Solution: Since all the users will be managed in Office 365, you can remove all on-premise infrastructure, which are: • Exchange Servers • DirSync/AD Connect (ADDSync) • ADFS • Public Folder

Actual End State of Decommission Exchange Servers

Per Microsoft, all the items will have to be removed, and no one component can stay up to be a supported architecture.

Question: Can I remove the Exchange Server and keep my AD Connect? From Microsoft’s perspective, the main concern with uninstalling the on-premises Exchange Server is that the Exchange attributes get wiped on the on-premises AD users, and those changes then get synced to Office 365 and Azure AD.

Some of the Attributes that get removed: | Attributes | Description | |——|————-| |mail | This is an attribute in Active Directory, the value of which represents the email address of a user | |msExchMailboxGUID | This is an attribute which defines the user’s mailbox globally unique identifier (GUID) | |msDsConsistencyGUID | This is an attribute is Azure AD Connect (version 1.1.524.0 and after) now facilitates the use as sourceAnchor attribute | |proxyAddresses | This is an attribute is a multi-value property that can contain various known address entries | |legacyExchangeDN | This is an attribute value when a mailbox is created, and includes the name of the Exchange administrative group where the mailbox belongs |

So, it is not supported, and you will have to keep Exchange installed and running

https://docs.microsoft.com/en-us/exchange/decommission-on-premises-exchange
This post is licensed under CC BY-SA 4.0 by David Marker