Zoho Mail Split Delivery

If you use Zoho Mail for your primary mailboxes but want ImprovMX to handle catch-all addresses or specific aliases, you can configure split delivery. Zoho Mail will handle known users while forwarding unrecognized recipients to ImprovMX.

Prerequisites

• Full admin access to your Zoho Mail Admin Console
• Your domain's MX records pointing to Zoho Mail with higher priority than ImprovMX
• Recommended: Disable strict MX verification alerts if applicable

Step 1: Configure Email Routing

First, add ImprovMX as a routing destination in Zoho Mail.

1. Open the Zoho Mail Admin Console
2. Navigate to Mail Settings > Email Routing
3. Click Configure routing or Add
4. Select your domain from the dropdown
5. Enter the destination host details:
   • Primary host: mx1.improvmx.com
   • Secondary host: mx2.improvmx.com
6. Specify a verification email address — use an alias configured in ImprovMX that does not exist in Zoho Mail
7. Enable TLS and certificate validation if available
8. Click Add and wait for verification confirmation

Step 2: Set Routing Type to Split Delivery

Configure Zoho Mail to use split delivery for your domain.

1. In the Email Routing configuration, go to Basic Settings
2. Under Type of Email Distribution, select Split Delivery
3. This setting tells Zoho Mail to:
   • Deliver emails to existing Zoho Mail accounts
   • Forward emails for unknown accounts to the destination host (ImprovMX)
4. Optionally, enable Do not retain Zoho Mail copy to prevent duplicate storage
5. Click Save

Step 3: Configure ImprovMX Aliases

In your ImprovMX dashboard, create the aliases you want to forward. For example:

• info@yourdomain.com → your-personal@gmail.com
• * (catch-all) → catchall@gmail.com

Step 4: Test the Configuration

After saving your settings:

1. Send a test email to a Zoho Mail user — it should be delivered to their Zoho mailbox
2. Send a test email to an ImprovMX alias — it should be forwarded to your configured destination
3. Monitor for successful delivery or any bounce notifications

Note: Ensure all your ImprovMX aliases are properly configured before testing. Zoho Mail will relay emails for unknown accounts to ImprovMX.

SPF Configuration

When using both services, combine the SPF records into a single TXT record:

v=spf1 include:zoho.com include:spf.improvmx.com ~all

Note: Use include:zoho.eu or the appropriate regional include if you are on Zoho's EU or other regional data centers.

See our guide on combining SPF records for more details.

Advanced Routing Options

Zoho Mail also offers additional routing options you can customize:

• Criteria-based routing: Route emails based on specific conditions
• Group member routing: Route based on group membership
• Recipient routing: Route based on recipient addresses

Refer to Zoho's Email Routing documentation for more details.