Zero-Downtime Email Migration

Migrating email is trickier than migrating a website. If you just flip the MX records, you’ll lose emails sent during propagation (some servers deliver to the old host, some to the new). Here’s how to do it with zero lost messages.

The Problem link

When you change MX records, DNS propagation takes up to 48 hours. During that window:

• Some senders’ DNS caches still point to the old mail server
• Other senders see the new MX records and deliver to GoZen
• Emails sent to the old server during propagation can be lost if you’ve already cancelled that account

The Zero-Downtime Process link

Phase 1: Set Up Email Accounts on GoZen (Before Changing Anything) link

1. Log into cPanel on your GoZen Host account
2. Go to Email > Email Accounts
3. Create every email account that exists on your old host, using the same addresses
4. Set passwords for each account

Don’t change DNS yet. Just create the accounts.

Phase 2: Sync Existing Emails link

Transfer your existing emails from the old host to GoZen so you have a complete history:

Option A: IMAP Sync with imapsync (fastest for large mailboxes)

If you have SSH access on either server:

  imapsync \
  --host1 old-mail-server.com --user1 you@yourdomain.com --password1 "oldpassword" \
  --host2 mail.yourdomain.com --user2 you@yourdomain.com --password2 "newpassword" \
  --ssl1 --ssl2
  

This copies all folders, messages, and flags from the old server to GoZen.

Option B: Email Client Drag-and-Drop

1. Add both email accounts to Thunderbird or Outlook (old server and GoZen server, using different IMAP server names)
2. Select all messages in each folder on the old account
3. Drag them to the corresponding folder on the GoZen account
4. Wait for the sync to complete

Option C: Contact Support

Open a support ticket and we’ll handle the migration. Include your old server’s IMAP details.

Phase 3: Change MX Records link

Now that accounts are created and emails are synced, point your MX records to GoZen:

1. Go to your domain registrar’s DNS management
2. Update the MX records to GoZen’s mail servers (check your welcome email for the exact values)
3. Keep the old email account active during this phase

Phase 4: Dual Delivery Period link

For the next 48 hours, emails might arrive at either server. To catch everything:

1. Keep the old email account active and check it periodically
2. Set up forwarding on the old host: forward all incoming email to the same address at GoZen. Most hosting providers let you configure email forwarding in their control panel
3. Monitor both inboxes for 48 hours

Phase 5: Clean Up link

After 48 hours:

1. Verify that all new emails arrive at GoZen (check your GoZen webmail)
2. Do one final sync from the old server to catch any stragglers
3. Update your email client to point to GoZen’s mail server
4. Cancel the old hosting account (only after confirming everything works)

Updating Email Clients link

After migration, update your email clients (Outlook, Thunderbird, mobile) to use GoZen’s server:

See Gmail Setup and Outlook Setup for step-by-step guides.

Email Authentication link

After the MX records point to GoZen, set up SPF, DKIM, and DMARC to keep your emails out of spam folders:

1. In cPanel, go to Email > Email Deliverability
2. Click Repair next to your domain if there are warnings
3. Verify at GoZen DNS Inspector

See Email Delivery Problems for full setup details.

What to Do Next link

• Setting Up Email Accounts in cPanel - configure your email accounts
• Email Delivery Problems - fix deliverability after migration
• Set Up GoZen Email in Gmail - access your new email from Gmail