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Configure Dual Delivery


When you change the MX Records of your domain to Zoho, all the emails addressed to your domain starts arriving in Zoho. This is direct email delivery. Apart from the direct email delivery, you can also configure dual delivery or partial delivery to Zoho Mail Servers. The Dual Delivery or Split Delivery can be configured in your Legacy Servers or in Zoho Servers. This will be helpful for users who are in the transition phase, and want to evaluate the Zoho Mail Services parallely without completely discontinuing the current Email Services. This will also ensure Business continuity when you switch the Email Service from one provider to the other. 

Dual Delivery through Zoho Email Server

You may choose the Zoho Mail Server as your primary server. In this case, the MX entries should be pointed to Zoho. You can configure dual delivery in Zoho Mail server, to route a copy all the incoming emails to your legacy server. 

Split Delivery through Zoho Email Server

Even in this case, Zoho will act as the primary server. The email routing in this case will happen a little differently, compared to the previous scenario. The email accounts which exist in Zoho will receive the email here itself. When emails are addressed to email addresses that are not in the Organization setup in Zoho, those emails will be routed to the other server. The option is currently in beta and will be made available to users upon request.

Steps to configure Email Routing (Delivery Options) through Zoho Email Servers :

If you want to route the emails to your domain in Zoho to other servers, you can configure Email Routing or use the Delivery options available in Zoho Mail. 

  1. Login to https://www.zoho.com/mail as Super Administrator
  2. Click Control Panel >> Email Routing >> Email Delivery Options
  3. Domain: Select the domain for which you want to enable Email Routing. 
  4. Email Delivery Options: 
    1. Split Delivery : When you select Split delivery, when the emails are addressed to accounts present in Zoho Servers, email is delivered to Zoho Mail only. If the emails are addressed to non existent email addresses, the emails will be routed to the servers or the domains mentioned in the Destination section. 
    2. Dual Delivery: When you select Dual Delivery, when the emails are addressed to accounts present in Zoho Server, the emails are delivered to Zoho Mail and also to the selected Destination servers. If the emails are addressed to non existent email addresses, the emails are bounced back to the original senders with the error messages. 
    3. Email Routing: When you select Email Routing, all the emails will be routed to the destination servers, irrespective of whether the email accounts are present in Zoho or not. 
  5. Destination: The destination can be MX records of other servers or another domain. Provide the destination to route the emails. You need to provide the other destination MX servers or another domain which you may have, which can receive the email based on the domain. This can be your legacy server (old email servers) or servers where you want to have a back up of the emails. If you provide another domain, the emails will be delivered to the MX records of that domain. 
  6. Verification Email Address : Provide the verification email address in the destination server, using which the routing can be tested. We will send a test email, to check if the destination server accepts the email. Only if the test is successful, the routing will be enabled. 
  7. Change SMTP envelope: When you provide a domain name instead of the MX servers, the SMTP envelope can be changed. i.e If the email is sent to you@yourdomain.com where yourdomain.com is the domain you have in Zoho, if Change SMTP envelope is selected, the email will be routed to you@otherdomain.com. Generally change SMTP envelope is required when you provide the domain name in the destination option. 
  8. Send bounce when the email to the destination fails: If you select On, if the destination server bounces the email, the undelivered notice will be sent to the original sender of the email. 
  9. Status for the Advanced Delivery option: The Email routing will be enabled only if this option is turned ON. When the option is Off, the settings will be saved for a later usage. 

Note: In this case you need to be sure whether the email account needs to be present in Zoho or in the other server, and create the account in either of the server to avoid any loss of data. Also when you configure dual/ split delivery in Zoho Servers, the email routing will be disabled if the number of bounces from your secondary servers exceeds the threshold limit. The other Email server needs to be configured to accept the emails relayed from Zoho Mail. Ideally, you can white-list the IP addresses or configure Inbound gateway in the secondary servers. You may configure the Catch All accounts in the secondary servers, to avoid any bounce and subsequent disabling of routing settings. 

Important Note:

In both cases, it is essential to setup SPF records mentioning both the server details as valid servers for your domain. 

Dual Delivery through your Legacy Email Server

In case you wish to use you legacy server as the primary email server, the MX entries need not be changed. You can configure dual delivery in your legacy server, to route a copy of incoming emails to Zoho or configure your email server in such a way that the emails for a set of email addresses get routed to Zoho Mail Server. 

You need to configure the inbound gateway in Zoho Mail Control Panel, to authorize incoming emails from that other IP address to your domain accounts in Zoho Mail. 

Configuring Inbound Gateway in Zoho Mail:

When you configure dual delivery or routing through your existing servers, you need to configure inbound gateway in Zoho Mail control panel. 

  1. Login to https://www.zoho.com/mail
  2. Click Control Panel >> Email Routing >> Inbound Gateway
  3. Provide the IP address from which the emails will be delivered to your domain. 
  4. Click the plus icon to specify multiple IP addresses from which email will be routed to your domain. 

 Configuring Dual Delivery in Google Apps

If you are currently using Google Apps as your Server, you can set up dual delivery in Google Apps to deliver a copy of all incoming messages to Zoho. To forward messages for the entire domain:


  1. Log into the Google Apps control panel for your domain.
  2. Click the Settings tab and then select Email in the left column.
  3. In the Email routing section, click Add another destination.
  4. In the Destination box, enter zoho.com.
  5. Specify which accounts the mail server applies the routing rule to by selecting a Deliver email for option.
    • To forward all messages that the Google Apps mail server receives, select Provisioned accounts, if you want to duplicate the user set up in Google Apps here.
    • Select ‘Unknown Accounts’ to route the emails, addressed to non-existing email addresses to Zoho.
  6. Select ‘Send Bounce Notifications’ as per your requirement.
  7. Click Save changes.

Configuring Dual Delivery in Exchange

You need to decide on the number of ‘Pilot’ Test users for whom you want to set up Dual Delivery in Exchange. Unlike Zoho, email forwarding or email delivery cannot be set up at the Exchange level for the domains. To configure dual delivery in Exchange, you need to set up Contact Objects for the Pilot users, and configure each user account to Forward the domain email to the contact email.

Creating New Mail Contact

  • Start the Exchange Management Console.
  • In the console tree, expand Recipient Configuration, and then click Mail Contact.
  • In the action pane, click New Mail Contact. The New Mail Contact wizard appears.
  • On the Introduction page, in Create a mail contact for, click New contact, and then click Next.
  • On the Contact Information page, complete the following fields:
    • Organizational unit By default, the New Mail Contact wizard displays the path to the Users container in the Active Directory directory service. To modify this field, click Browse, and then select the organizational unit (OU) that you want.
    • First name Type the first name of the contact. This field is optional.
    • Initials Type the initials of the contact. This field is optional.
    • Last name Type the last name of the contact. This field is optional.
    • Alias By default, the alias is the first name, initials, and last name of the contact, separated by underscore characters (_). You can modify this field.
    • External e-mail address To specify the external e-mail address, perform one of the following tasks: To specify a custom e-mail address, click the arrow next to Edit, click Custom Address, and then in E-mail address, type the e-mail address.
  • On the New Mail Contact page, review the configuration summary, which contains information about the options that you selected for the new mail contact. To make changes, click Back. To create the new mail contact, click New.
  • On the Completion page, the summary states whether the contact was successfully created. The summary also displays the Exchange Management Shell command that was used to create the new mail contact.
  • Optional: To avoid confusion, hide the newly created Contact object from the Exchange Global Address List for your domain, as follows:
    • In the Exchange Advanced tab, check the box next to Hide from Exchange address lists.
    • Click Ok to save the changes.
  • Click Finish to complete the task.
  • Repeat the steps for each pilot Contact you want to add.

Configure Forwarding to the Mail Contact:

  1. Start the Exchange Management Console.
  2. In the console tree, expand Recipient Configuration, and then click Mailbox.
  3. In the result pane, right-click the mailbox for which you want to configure mail forwarding and click Properties.
  4. In Properties, on the Mail Flow Settings tab, click Delivery Options, and then click Properties.
  5. Click the Forward to check box. This enables the Browse button.
  6. Click Browse to open the Select Recipient dialog box. click OK.
  7. To deliver incoming messages to the mailbox as well as to the forwarding address configured, select the Deliver message to both forwarding address and mailbox check box.
  8. Click OK to return to Properties.
  9. Click OK.
  10. Repeat the steps for configuring forward to Zoho for each Pilot user you have set up.

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