You can move your users to the OpenSRS Email Service with little or no disruption when you plan ahead. The full migration breaks into four phases: preparation (about three weeks out), pre-migration (about one week out), migration (cutover day), and post-migration. This article walks through what to do in each phase, both in your current system and inside the OpenSRS Reseller Control Panel.
About the four migration phases
Each phase has tasks in your existing system and tasks inside OpenSRS. Treat the recommended timing as a guide and adjust to suit your customer base. The earlier you start, the smoother the cutover.
Before you begin
- Inventory the domains, mailboxes, and aliases you plan to migrate.
- Identify whether your end users connect via IMAP, POP3, webmail, or all three.
- Note your current DNS TTL values for MX and any mail hostnames.
- Confirm your branding and default company preferences are ready in the Reseller Control Panel.
- Communicate with end users at least three weeks before cutover.
Step 1: Prepare (about three weeks out)
In your current system
Required
- At least two weeks before cutover, lower the TTL on the MX and any mail hostnames to less than an hour (300 seconds recommended). Note the previous TTL.
Recommended
- Notify users that their accounts are moving and that they will need to reconfigure web-based signatures, auto-replies, forwarding, and filters afterward. Use the OpenSRS communication templates.
- Encourage users to back up address books to vCard and calendars to iCal (.ics) so they can re-import after migration.
- Introduce users to the OpenSRS platform and what to expect.
In the Reseller Control Panel
Required
- Set up branding for the domains you'll migrate and make it the default brand.
- Set default company preferences: branding, account limits, language, time zone.
Step 2: Pre-migrate (about one week out)
In your current system
Required
- Stop provisioning new accounts on the old system.
- Block password changes on the old system, typically by hiding the password preference page.
Recommended
- Tell users that changes to their address books or calendars after the extract date won't carry over.
- Confirm address book field headers are in a format the OpenSRS Email Service recognizes. Test by importing a sample.
- Extract each user's address books to vCard and calendars to .ics.
- Email each user their vCard and .ics files with instructions to re-import after cutover.
In the Control Panel
Required
- Create the same users in OpenSRS before changing DNS. If you have encrypted passwords (Unix-Crypt, MD5-Crypt, SHA, or BCRYPT), you can reuse them.
- For small numbers of accounts, create them manually. For larger numbers, use Bulk Add or the API. See Bulk Tools.
- You can create up to 1,000 accounts at a time; provisioning is real-time.
Step 3: Migrate (cutover day)
In your DNS system
Required
- Change DNS to point to OpenSRS. See Configure DNS for OpenSRS Hosted Email.
- Set the correct MX record and CNAME for your cluster. See Which Email Cluster Am I On?. The MX record is required; the CNAME is recommended.
- Wait for DNS to propagate. With the lower TTL set during preparation, propagation should be quick, but allow up to an hour before considering users fully cut over.
- Re-enable provisioning, directing new account requests at OpenSRS.
Recommended
- Add the RFC 6186 DNS entries so compatible email clients can auto-configure hostnames and ports, including SSL settings.
- Once the new TTL has elapsed, disconnect IMAP sessions on the old server. IMAP sessions can be long-lived and may otherwise stay on the old system.
In the Reseller Control Panel
Required
- Use the email migration tool to pull user mail over IMAP or POP. See How to Use the Email Migration Tool.
- Migrate up to 500 accounts per batch. Run batches one at a time.
- Track ongoing migrations from Bulk Actions in the user menu (top right).
- You can log out or do other work in the Control Panel; running jobs continue.
- Re-run any failed migrations. The tool prevents duplicate messages.
- Re-enable account provisioning.
Step 4: Switch to OpenSRS DNS
- In the DNS section of the Reseller Control Panel, duplicate your existing DNS entries.
- Change the authoritative nameservers to OpenSRS nameservers.
Note: You can do this step before the migration. OpenSRS can become authoritative ahead of mail cutover — mail flow and DNS lookups remain unchanged as long as the records match.
Step 5: Post-migrate
In the Reseller Control Panel
Recommended
- Begin provisioning new accounts in OpenSRS.
- Remind users how to import their saved vCard and .ics files.
- Reintroduce users to the OpenSRS platform.
Next steps
- Run a migration job — see How to Use the Email Migration Tool.
- Bulk-provision destination accounts — see Bulk Tools.
- Update DNS — see Configure DNS for OpenSRS Hosted Email.
- Anticipate transient SSL warnings — see Email Migration Service Interruptions.
- Download the timeline — OpenSRS Email Migration Timeline PDF.
Questions? Contact OpenSRS Support.
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