Zoho Mail provides four email delivery types, each suited to a specific routing scenario:

• Split Delivery: Delivers emails to existing Zoho Mail accounts while redirecting emails for non-existing accounts to a destination server instead of bouncing them.

• Dual Delivery: Delivers emails to both Zoho and an external server simultaneously for all existing accounts. Best suited for organizations maintaining an email backup or running two systems in parallel.

• Email Routing: Routes all incoming emails to a configured destination server, regardless of whether the account exists in Zoho.

• Custom Routing: Routes emails for specific accounts based on administrator-defined rules and criteria.

Inbound and Outbound Gateways   

Organizations that use third-party services for email backup, archival, or retention may need all emails to pass through those systems before reaching or leaving Zoho Mail. This is achieved by configuring Inbound and Outbound Gateways.

• Inbound Gateway: When your domain's MX records point to a legacy or third-party server, you can configure those servers as an Inbound Gateway. Emails relayed from these trusted servers to Zoho Mail are recognized as legitimate and accepted for your organization.

• Outbound Gateway:  Configure an external server as the Outbound Gateway to ensure all outgoing emails pass through it before delivery. This is commonly used for email archival, retention, compliance, or backup purposes.

When should admins use Email Routing? 

 Email Routing is particularly useful in the following scenarios:

• During email migrations: Use Split Delivery to ensure uninterrupted email delivery while users are gradually migrated from a legacy mail server to Zoho Mail.

• Maintaining email backups or archives: Configure Dual Delivery to ensure every email is delivered to both Zoho and an external archival system simultaneously.

• Handling emails for non-existing accounts: Route emails to a designated server instead of bouncing them, especially when migrations are still in progress.

• Filtering emails through a spam gateway: Configure an Inbound or Outbound Gateway to ensure all incoming or outgoing emails pass through a third-party spam filtering service. This provides an additional layer of protection against spam, malicious emails, and other security threats.

• Meeting compliance and retention requirements: Route emails through third-party archival or retention systems to meet regulatory or organizational policies.

Steps to configure Email Routing in Zoho Mail Admin Console 

1. Log in to Zoho Mail Admin Console.

2. Navigate to Mail Settings in the left pane and go to Email Routing.

3. In the Email Routing section, click the Configure routing button under Configuration to begin setting up email routing.

4. Select the domain for which you want to enable Routing from the drop-down list.

5. Provide the Destination host to which you want to route the emails. You can enter either the Domain name, Smart host, MX or the IP Address.
   

6. Enter other relevant details and click Add. This verification process may take a while before the routing configuration gets added.
   

Know in detail about the Email Routing configuration in Zoho Mail Admin Console.