Deliver email to multiple inboxes with dual delivery

Send incoming messages to two or more inboxes

If you want to send your organization's email to two or more inboxes, set up dual delivery. With dual delivery, messages are delivered to a Gmail inbox and to your legacy, non-Gmail system For example, you might want to deliver email to Gmail and to Microsoft Exchange or to an archiving server.

Incoming mail is delivered to the primary mail server first. The primary server is the mail server identified in the MX records for your public domain. The primary server delivers each message to the inboxes associated with it, and then forwards all messages to a secondary mail server. The secondary server delivers the messages to the secondary server inboxes.

With dual delivery, the primary server can be either Gmail or your legacy mail server. We recommend you always use Gmail as the primary server. However, you might use your legacy server as primary during a pilot or migration to Gmail. When your pilot ends, and you're ready to switch everyone to Gmail, update your email delivery to Gmail only.

Step 1: Add your legacy server in the Admin console

Before you can set up dual delivery, you must add your non-Gmail server with the Add Route setting.

Step 2: Set up dual delivery

After you add the legacy server with the Add Route setting, you’re ready to set up dual delivery. We recommend using Gmail as your primary server. If you must use your legacy server as the primary server, go to Option 2: Dual delivery—Legacy server as primary server.

Option 1: Dual delivery—Gmail as primary server (recommended)

The steps below describe the minimum required steps for setting up dual delivery. You can optionally choose more options in the routing setting. For details about all options available in the Routing setting, refer to Add Gmail Routing settings.

Sign in to your Google Admin console.
Sign in using your administrator account (does not end in @gmail.com).
In the Admin console, go to Menu AppsGoogle WorkspaceGmailRouting.
To apply the setting to everyone, leave the top organizational unit selected. Otherwise, select a child organizational unit or a configuration group.
On the Routing tab, click Configure or Add Another Rule.

In the Add setting box, take these steps:

Setting option	What to do
Routing	Enter a descriptive name for the address map. If you don't enter a name, you can't save your setting.
Email messages to affect	Select Inbound, or Internal-receiving, or both: Inbound—Incoming messages from external senders are delivered to both the primary and secondary server. Internal-receiving—Incoming messages from internal senders are delivered to both the primary and secondary server. Messages from internal senders have your organization's domain or subdomain in the From field.
For the above type of messages, do the following	Click the menu and Select Modify message.
Modify message	Select these options to set up dual delivery for affected messages: Scroll to Also Deliver to, and check the Add more recipients box. The Recipients table is shown. Beneath the Recipients table, click Add. The Add setting box appears. At the top of the Add setting box, click the menu and select Advanced. Beneath Route, check the Change route box. Beneath Change route, click the menu and select the server you added in Step 1: Add your legacy server in the Admin console. (Optional) Leave the 2 boxes beneath Spam and delivery options checked: Do not deliver spam to this recipient Suppress bounces from this recipient At the bottom of the Add setting box click Save. The new route appears in the Recipients table. At the bottom of the Add setting box, click Save.

At the bottom, click Save.
Changes can take up to 24 hours but typically happen more quickly. Learn more You can monitor changes in the Admin console audit log.

Option 2: Dual delivery—Legacy server as primary server

You may want to use your legacy server as the primary server for dual delivery. For example, to pilot Gmail with a few users during your trial period. Otherwise, we recommend Option 1: Dual delivery—Gmail as primary server.

Keep the following in mind when using your legacy server as the primary server:

Don't update your MX records to Google.
To set up server-based forwarding, you’ll need to sign into your domain provider. Make sure you have your username and password for your domain provider.
Google doesn’t support issues with third-party servers. If you need help with setting up your legacy server for dual delivery, check the help center for your server or contact the server vendor.

To use your legacy server as the primary server, use one of these methods:

Set up server-based forwarding from your legacy server to Google (recommended).
If your legacy server doesn’t support server-based forwarding, set up the server to forward messages to test domain aliases.

Server-based forwarding (recommended)—Legacy server as primary server

Set up server-based message forwarding on your legacy server. Email is delivered to the legacy server first. Then, messages are forwarded to Gmail.

Sign in to the management console for your domain host and locate the page where you update MX records for your domain.
Confirm that your MX records refer to the legacy mail server.
Set up the legacy server to forward all email to ASPMX.L.GOOGLE.COM.
Set up the legacy server as an inbound gateway, following the steps Set up an inbound mail gateway:
- Set up Gmail to get a high volume of mail from the legacy server.
- Improve SPF check accuracy. Mail coming from an inbound gateway is treated as an internal message. SPF checks are made against the server that sent the message to your legacy server.
Send test messages to each user's legacy server email address.
Verify that users get the test messages in both their legacy server inbox and their regular Gmail inbox.

Forward messages to test domain aliases—Legacy server as primary server

If your legacy server doesn't support server-based forwarding, use this option.

When you set up mail forwarding to a test domain alias, the legacy server forwards incoming messages to each person’s test domain alias. The message is then sent from the test domain alias to the person’s main Gmail account. Learn about domain aliases.

About test domain aliases

Your Google Workspace account comes with a test domain alias. Each users in your Google Workspace account is automatically assigned a test domain email address:

Test domain alias format: domain-name.test-google-a.com
Test domain email format: username@domain-name.test-google-a.com

For example, if your domain is solarmora.com, your test domain aliases are:

Test domain alias: solarmora.com.test-google-a.com
Test domain email: janedoe@solarmora.com.test-google-a.com

Learn more about test email addresses.

Secondary domain alias emails

Only your primary domain is assigned a domain alias and corresponding email addresses. If your users' email addresses are not part of the primary domain, create a secondary domain.

Update the MX records for the secondary domain to point to Google.

Set up forwarding to users’ test domain alias:

Set up mail forwarding on your legacy server. Messages sent to legacy email addresses are forwarded to the person’s corresponding test domain alias. Typically, forwarding rules are set up on a per-user basis.
Set up the legacy server as an inbound gateway, following the steps Set up an inbound mail gateway:
- Set up Gmail to get a high volume of mail from the legacy server.
- Improve SPF check accuracy. Mail coming from an inbound gateway is treated as an internal message. SPF checks are made against the server that sent the message to your legacy server.
Send test messages to each user's legacy email address.
Verify that users get the test messages in both their legacy server inbox and their regular Gmail inbox.

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