Mail migration is transferring messages from the old system to the new mail service and directing the new incoming mail to the correct system. When data copying, DNS change, and user migration are planned as separate steps, it becomes easier to spot errors and manage rollback.
What inventory is taken prior to migration?
List public addresses, aliases, groups, and redirects next to personal boxes. Mailing web forms, printers, accounting application and CRM should also not be forgotten. Archives kept on the local computer may not be the same as the content on the server.
The access method, approximate volume, data type, and job principal should be recorded for each bin. Instead of sharing credentials in an open email or public file, choose a limited-access transfer method.
Which transportation method to choose?
The source system, target system, and type of data to be moved determine the method. Don't assume that a tool that only copies messages also moves calendar, contacts, and authorizations. Microsoft also defines separate migration options for different resources.
Technical reference: Microsoft Learn — Email migration methods.
First, choose a small and representative pilot group: different examples such as the large archive, the public address team, and the mobile user. The purpose of the pilot is to see not only the transfer speed but also the missing functions.
At what stage is DNS change made?
Do not change MX routing until target accounts and pilot testing are ready. Designate people responsible for source copying, synchronizing final differences, and routing incoming mail to the destination. When to close the old service should be decided once the acceptance criteria have been completed.
Due to DNS caches, it is not expected that every sender will see the same system at the time of switching. How to check new messages generated on both sides and combine them when necessary should be included in the transition plan.
How to understand that the migration is over?
- Check old and new dated messages, attachments, and folders in sample boxes.
- Try sending, receiving, replying, and public address usage.
- Authenticate phone and desktop applications with the user.
- Close error and skipped item reports with the job principal.
- Consider the written terms of acceptance and return before closing access to the legacy system.
Based on available provider, number of users and data types corporate e-mail transportation You can clarify its scope.
Related resources
For application and enterprise support coverage Corporate Mail Transport Service You can review the page.
Official sources
Technical documentation and legislation may change; The relevant version and current text should be checked before application.
Frequently Asked Questions
Is it necessary to move the domain name as well?
It's not always necessary. Changing the e-mail service and changing the domain name registrar are separate processes.
Can old boxes be used during transportation?
It depends on the method chosen and the migration schedule. Data differences that will arise from the use of dual systems should be planned from the beginning.