Deliver email to multiple inboxes with dual delivery

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 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.

Before you begin: Add your legacy server in the Admin console

Before you set up dual delivery, add your non-Gmail server with the Add Route setting. This step is required when using Gmail as the primary server.

Although this step isn't required when using a legacy server as the primary server, we recommend it for other use cases. For example, you'll need a host if you use compliance rules to route messages from Google servers  to legacy servers.

Set up a dual delivery method

After adding the non-Gmail server, you’re ready to set up dual delivery using one of the following options:

Option 1: Gmail as the primary server (recommended)

Option 2: Legacy server as the primary server

Option 1: Gmail as the 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.

1. Sign in to your Google Admin console.

   Sign in using your administrator account (does not end in @gmail.com).

2. In the Admin console, go to Menu  AppsGoogle WorkspaceGmailRouting.
3. (Optional) To apply the setting only to some users, at the side, select an organizational unit (often used for departments) or configuration group (advanced). Show me how

   Group settings override organizational units. Learn more

4. On the Routing tab, click Configure or Add Another Rule. 

5. 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. A domain is internal if it is a verified workspace domain, or a subdomain or parent domain of a verified workspace domain.
   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.

6. Click Save. Or, you might click Override for an organizational unit.

   To later restore the inherited value, click Inherit (or Unset for a group).

   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: Legacy server as the primary server

Although we recommend you use Gmail as the primary server for dual delivery, there may be times when you want to use your legacy server as the primary server. For example, to pilot Gmail with a few users during your trial period.

When using your legacy server as the primary server, keep in mind:

• Don't update your MX records to Google.
• You’ll need to sign into your domain provider to set up server-based forwarding. 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)

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

1. Sign in to the management console for your domain host and locate the page where you update MX records for your domain.
2. Confirm that your MX records refer to the legacy mail server.
3. Set up the legacy server to forward all email to ASPMX.L.GOOGLE.COM.
4. 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.
5. Send test messages to each user's legacy server email address.
6. Verify that users get the test messages in both their legacy server inbox and their regular Gmail inbox.

Forward messages to test domain aliases

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.

Set up forwarding to users’ test domain alias:

1. 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.
2. 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.
3. Send test messages to each user's legacy email address.
4. Verify that users get the test messages in both their legacy server inbox and their regular Gmail inbox.

Related topics

• Send email to two email systems with split delivery
• Email routing and delivery options for Google Workspace