How to Migrate Exchange to Office 365: Step by Step

  • When planning an Exchange to Office 365 Migration, it can be quite confusing to understand what steps to take and in what order.


    This article describes the steps and decisions you must make when migrating to Exchange Online. In Part 1 we will consider the first two most important steps: deciding on a migration approach and taking the central steps for identity. We do the hybrid configuration of Exchange and we do the mailbox migration.


    Although we will cover a lot of information in no time, you will find detailed instructions at all times.


    Prepare to migrate from Exchange to Office 365


    Before starting the migration, you must ensure that the source environment you are migrating from is in good condition.


    If the Exchange environment you're running today is unhealthy, this can often serve as a motivator for getting around. What could be an easier solution for Exchange's low daily performance than switching to Office 365?


    If you have everyday problems with Exchange, p. For example, user issues with remote access to Exchange, error messages, and slow mailbox access times, or worse, database corruption, switching to Office 365 is most likely another problem; Not only for people accessing the environment you want to migrate from, but also during migration, as errors are likely to occur along the way.


    The first step before starting a migration should be to make sure that the environment is reasonably error-free and fix any underlying issues before migrating.


    Hybrid migration or tool-based migration?


    If you are considering moving your Exchange environment to Office 365, you probably know that there are many options available.


    From Microsoft, you have options for staged migration and transition migration, as well as hybrid migration, and third-party providers have a variety of different tools in the mailbox and email file migration market.


    If you have a Microsoft-compatible version of Exchange Server (Exchange Server 2010 and later) and it's part of your Active Directory, your default should generally be an Exchange hybrid migration.


    An Exchange hybrid builds on a minimal or full Exchange hybrid and creates a relationship between your on-premises Exchange servers and Exchange Online. This allows movements of native mailboxes, similar to those made between local Exchange servers, with Outlook clients that switch natively without having to download copies of emails offline again. With Full Hybrid, this also extends to the secure flow of messages between the two environments and to coexistence features such as free / busy and free calendar.


    Azure AD


    Azure AD Connect complements Exchange Hybrid. You must use hybrid if you want to sync your identity with the cloud. Azure AD Connect synchronizes your on-premises Active Directory domain with Office 365 and creates a copy of the on-premises AD accounts in Azure Active Directory that are linked to the master copies. Azure AD Connect is also the part of the puzzle that maintains a consistent global address list between installations and the cloud.


    Because AD and Azure AD Connect understand when an existing Exchange organization exists, existing mailboxes on the site do not create Office 365 mailboxes. You are expected to use Exchange Hybrid to move mailboxes.


    The same rules do not apply to tool-based migration. A fully hybrid-compatible Exchange hybrid migration provides an excellent experience. However, the correct configuration can be complex, particularly in environments with multiple forests. Azure AD Connect or Exchange Hybrid often cannot be configured in hosted environments. If you have earlier versions of Exchange, you can install additional Exchange 2010 or later servers that contain the hybrid components. Therefore, there are valid uses for an Office 365 custom migration tool. However, this article assumes that you have chosen Exchange Hybrid.


    Understand the requirements and dependencies.


    If you have decided that migrating to Office 365 with Exchange Hybrid is right for your business and you have a healthy migration environment, you need to make sure that you have completed the necessary planning activities.


    Many organizations beginning this journey at this point will ensure that they have a design that supports the changes that will take place. However, since you are not designing Office 365 or Exchange Online and instead are designing the bridge to Office 365, the design is often not as detailed as a full Exchange migration.


    Instead, focus on the changes that are required in your existing environment to make sure you are ready for the changes. We won't see that in this article, but it's worth noting that most large and small organizations don't just go into the unknown without making advance plans.


    The most important prerequisite for migration to Exchange is that the correct identity model is available. There are several options available when choosing an identity. However, the most common use is Azure AD Connect with synchronized identities and password hash synchronization.


    Before that, we performed a number of key tasks.