Migration from IMAP source to Exchange 2013/2016
I. Pre-migration activities
Below you will find the list of key points to be considered:
Step 1: Prepare a clean target Exchange environment in a new Active Directory forest
The following points need to be revised:
Step 2: Prepare domain accounts on the Target server
- Create mailboxes in the target environment.
Please be aware that for each user included in the migration, you must have mailbox-enabled user ready in the target environment prior to migration.
Step 3: Make sure that the Target server's Administrator belongs to the appropriate AD group, has permissions on users mailboxes and has his mailbox correctly configured
- Check if the Administrator belongs to the Organization Management group:
- Open the Exchange Management Shell on the target server and enter Import-Module ActiveDirectory script
- Then execute Get-ADPrincipalGroupMembership
- (Optional) Check the Administrator's impersonation rights on users mailboxes
Learn more on how to manually configure the impersonation rights
This step is optional as the software's target server connection wizard will attempt to assign impersonation rights for you.
- Check that the Administrator's mailbox is configured and activated
Step 4: Verify permissions of the software user and target server admin's account.
Make sure that the Target Server Admin, whose credentials are used, has proper access rights to the Target server's EWS service and that his mailbox is not hidden from the Exchange address lists
Verify the following:
- Domain Admins membership
- Organization management membership of the target server Administrator
- Access to the Target server's EWS service using FQDN or IP, e.g. https://[server-name.domain.com]/EWS/Exchange.asmx or https://[Exchange_IP]/EWS/Exchange.asmx
- If a Client connects to EWS from the outside of the local network he needs to have the external EWS URL correctly configured:
- Open the Exchange Management Shell on the target server and check if the ExternalUrl is defined: Get-WebServicesVirtualDirectory | fl
- If there's no address in the ExternalUrl line it needs to be defined. Execute the following script: Get-WebServicesVirtualDirectory | Set-WebServicesVirtualDirectory -ExternalUrl https://[Target server's internet name]/EWS/Exchange.asmx
Step 5: Adjust the EWS Throttling settings and change the maximum size limit of sent mail to decrease the time of migration processing
Step 6: Prepare source IMAP server settings
Verify the following:
- You have a list of all credentials for mailboxes you want to migrate via IMAP - here is why
- Know your IMAP server address or IP, port and SSL connection support - for example, for Google (whether Gmail or Google Apps) those are: imap.gmail.com, port 993, enabled SSL
- IMAP access is enabled on the source server - see here how to do this for Gmail and Google Apps accounts
Step 7: Installation of components required to install CodeTwo Exchange Migration (the installation wizard will guide you through this process)
- MAPI CDO (MAPI Client and Collaboration Data Objects, will be installed on all systems except for systems with coexisting MS Outlook x86 older than version 2016, MAPI will be used only if Exchange Server On-Premises is configured as a source)
- .NET 4.0 (required on any system, might be already installed)
Step 8: Installation and activation of CodeTwo Exchange Migration
In the case of migration from IMAP the program can be installed anywhere e.g. on a workstation outside source and target domains, however, it will most likely works the best if installed directly on the target Exchange Server.
Please note that if you are about to migrate from both: IMAP source(s) and Exchange Server On-Premises you must install the software in the source Exchange Server environment, preferably directly on the source Exchange Server.
II. Migration process
Step 1: Connect to the Source server
Once the program's installation is completed, you will see the Dashboard view. Click Create a new migration job link on How to start tile. You will first encounter a question regarding the type of the source server. Once you choose IMAP server, a wizard will pop-up which allows you to configure connection to your IMAP source. You need to go through those steps:
- Server connection - in this step, you need to choose your IMAP source and some connection settings.
- Throttling - there you can customize the software behavior if you stumble upon throttling issues on the IMAP source server.
- Configuration - this step configures your connection based on the settings provided in the previous steps.
Step 2: Continue the job configuration to provide source mailboxes credentials
After successfully configuring the Source connection, Create migration job wizard will open. Set the name of the job and hit Next to define which mailboxes you want to migrate:
- Prepare a CSV file that contains source mailbox credentials as listed below. Do not worry that much about CSV format. CSV import feature lets you adjust the software to the file format used, e.g. you do not need to use a specific fields delimiter - use the one you like, you will be asked by the CSV import feature what kind of delimiter was used in the file.
- Login - required
- Password - required
- First Name - optional
- Last Name - optional
- Display Name - optional
- Click Import CSV and select your CSV file.
- Configure the software to properly import data from your CSV file.
Step 3: Set the Target connection
After successfully configuring the source connection and choosing source mailboxes, hit Next to define the Target server connection on the very next step:
- From the Target server combo box select Add new target connection... and wait until next wizard opens.
- On the step Server connection choose Autodiscover Exchange Server (default option) to automatically find the proper Target server. This will work flawlessly if you installed the software in the target server environment or in trusted domain. Otherwise you may need to configure the connection manually.
If you decided to configure the target connection manually, be aware that using either IP address or netBIOS name to connect to the target server will render listing target mailboxes and automatching impossible. Consequently, you will need to configure every source-target mailboxes pair manually, by typing in the target SMTP addresses. So, if possible, use FQDN address to define target server.
- Admin's credentials - specify the UPN of the Target server Administrator and its password. If you installed the software in the target server environment or in trusted domain you can click the Browse button to use AD user picker. Next, enter the Admin's credentials and move on to Configuration.
UPN (User Principal Name) is an Internal account name of a user in an e-mail address format.
- Configuration - this process configures the target server connection based on the entered settings.
- If any errors appear please consult the Learn more sections describing the most common configuration mistakes.
- Now is the time to test the Administrator's impersonation rights on the chosen Target mailbox. Under the Test button provide the Active Directory user's e-mail address and hit Test. If your rights have been successfully granted, you will be notified about that.
- Close this window, you will return to the IMAP job configuration wizard.
- Target mailboxes enumeration - choose one of the two available options:
- Read mailboxes from the target server - the software will connect to the target server and extract the list of all mailboxes. Use the Test button to verify the connection to your target server works.
- Import mailboxes from a CSV file - automatic mailboxes enumeration might take a while in big environments (thousands of mailboxes). Some admins prefer to export a list of mailboxes to a CSV file first and import it to the software to speed up the configuration process.
Step 4: Pair up source and target mailboxes
Matching the Source with the Target mailbox can be done in two ways: automatically via the built-in Automatch feature or manually. Use one of the below way to match mailboxes. Read more here on how to properly use all Automatch options.
- Automatch with patterns - this mechanism automatically matches the Source mailboxes with the corresponding Target mailboxes based on matching patterns, whether predefined in the software or user-configured.
- Automatch with a CSV file - this option allows you to provide a list of already matched source and target mailboxes in a CSV file. This will be of use if source and target mailboxes have nothing in common so it is not possible to find the right matching pattern to automatch mailbox pairs.
- Manual matching - allows you to manually assign target mailboxes to the source mailboxes one by one.
- If you chose this option, skip to Step 5 to complete the wizard and then come back here.
- On the Mailboxes list, hit Click to match target button for a desired mailbox. Then, either select the appropriate target mailbox from the list or type in the SMTP address.
- Click OK to confirm your decision. You must repeat the procedure for unmatched mailboxes.
Step 5: Customize all necessary aspects of the migration job
You may configure the following additional options:
- Scheduler - allows you to set the job to be automatically started in desired period of times, so you do not have to control it manually.
- Time filter - is used to exclude items that are older or newer than a particular date
- Folder filter - may completely exclude specific folders from the migration process
- Address rewrite - enables automatic conversion of EX addresses to the SMTP equivalents. This option needs to be enabled if you are performing cross-domain migration; otherwise you will not be able to reply to messages containing EX addresses.
- Concurrency - provides an option to define how many mailboxes should be migrated at same time. This number should correspond to the number of logical processors.
Step 6: Start the migration
Simply click Start on the ribbon to begin the migration.
The migration processing time depends on several different factors, e.g. the number of mailboxes and items, the speed of internet connection, EWS Throttling settings. We have published more details here.
Step 7: Check if the number of migrated items in the Target mailboxes matches the Source server mailboxes
If you notice any missing items in the Target mailbox restart the migration using the Rescan feature.
Please be aware that the program does not migrate some specific folders at all. Those are i.e. Sync Issues or ones created while putting a mailbox on a litigation hold.
If any problems appear during the migration process they will be indicated on the dashboard, pointed on the reports and logged in the log files. Check out the software's diagnostics.
Step 8: Check if there are any new items in the Source mailbox after migration
Once the migration is finished and you have noticed that some new items appeared in the migrated Source mailbox, just restart the migration using the Rescan feature. Please keep in mind that the Rescan feature uploads only new items, not changed ones.
III. Post-migration cleanup
Step 1: MX records
If you have your own domain pointed at source server you probably want it now to point at the new server. Change MX records with your domain registrar to enable mail flow to new servers instead of the old ones. Please note that this process may take several hours.
If any new items appear in a source mailbox while the MX records are being changed, it is possible to migrate them after the records' migration process is completed. It can be done using Rescan feature.