You can set up a domain-wide routing policy for inbound messages using Default routing.
For example, you can use Default routing to set up split delivery to route unregistered G Suite users to your on-premise mail server. This is useful when transitioning users from a legacy mail server to Gmail. You can also use Default routing to designate an existing user account as a catch-all address to receive messages that are addressed to non-existent users in your domain.
To set up routing settings, you specify recipient addresses, and then specify an action to perform on mail intended for those recipients. If you set up multiple routing settings, you can arrange the rules in order of priority. See Ordering your routing settings.
For more information about configuring split delivery, catch-all addresses, and other routing options, see Email routing and delivery.
Note: Default routing takes lower precedence than other advanced Gmail settings, such as Content compliance or Attachment compliance.Configure a default routing setting for a domain
From the Admin console Home page, go to AppsGoogle WorkspaceGmailDefault Routing.
- Click Configure to set up Default routing. Or, to add a new default routing rule, click Add another rule.
- From the list, select the envelope recipients to match:
- Single recipient—Specify a single user by entering an email address, such as firstname.lastname@example.org.
- Pattern match—Enter a regular expression to specify a set of recipients in your domain.
- Group membership—Select from one or more groups in the list. Create your groups from the Groups tab.
Note: This option affects both direct and indirect group members. For example, if Group B is a member of Group A, users in Group B are indirect members of Group A.
- All recipients—Specify all recipients in your domain. By default, this only affects unrecognized addresses.
- In the If the envelope recipient matches the above, do the following section, specify whether the message should be modified or rejected when the conditions meet the routing setting.
This option lets you modify messages by adding headers, changing the route, changing the envelope recipient, adding more recipients (additional, or secondary routes), and removing attachments.
See the following descriptions for more details about routing controls:Add X-Gm-Original-To header
By checking this box, a header tag is added in case the recipient is changed so that the downstream server can know the original envelope recipient; for example, X-Gm-Original-To: email@example.com.
Adding the X-Gm-Original-To header is useful if you're rerouting a copy of the message to another recipient. In this case, you're changing the recipient address, but the new recipient wants to know the address of the original envelope recipient. The new recipient can see the original envelope recipient by checking the X-Gm-Original-To header box in the message.
Messages that are routed through Gmail are automatically filtered for spam and phishing. Select Add X-Gm-Spam header and X-Gm-Phishy header to add the following headers to indicate the spam and phishing status of the message:
0 indicates that a message is not spam: X-Gm-Spam: 0
1 indicates that a message is spam: X-Gm-Spam: 1
0 indicates that a message is not phishing: X-Gm-Phishy: 0
1 indicates that a message is phishing: X-Gm-Phishy: 1
Note: Any message marked as phishy is automatically marked as spam.
Selecting the Add X-Gm-Spam header and X-Gm-Phishy header option lets an administrator at a downstream server set up rules that handle spam and phishing differently from clean mail.
You can add 1 or more custom headers to messages that are affected by a Receiving routing setting, Sending routing setting, or other setting. For example, you can add a header that matches the description that you entered for the setting. This can be helpful for analyzing why a message was routed in a certain way, or why a filter was triggered.
You can enter a string to prepend to the subject of messages. For example, if you enter Confidential, message recipients might see the following subject: [Confidential] Monthly report.
The Change route option lets you change the destination of the message. By default, the Gmail mail server is the primary delivery location. However, you can change the delivery location. For example, you can route mail to an on-premise mail server such as Microsoft® Exchange.
Before you can change the delivery location, you must first add mail routes for advanced Gmail delivery. The routes that you add on the Hosts tab are then visible in the route drop-down list.
Also reroute spam
The Also reroute spam option is visible when you check the Change route box. Also reroute spam lets you route all mail that matches the criteria of the setting, including mail that has been marked as spam. If you check the Change route box but do not check the Also reroute spam box, then normal mail is rerouted but spam mail is not rerouted. Spam messages are stored in the G Suite platform for 30 days.
- Whether you check the Also reroute spam box or not, blatant spam is not rerouted since it’s dropped instantly at delivery time.
- If mail is classified as spam but one of the Gmail settings overrides it (for example, due to a sender whitelist), then the mail is not considered to be spam for this purpose and will be rerouted as normal mail.
To change the envelope recipient, click the option next to the Replace recipient field, and enter the user's email address; for example, firstname.lastname@example.org.
Changing the envelope recipient for a message on the primary delivery is equivalent to forwarding a message to a different recipient. You can also change the envelope recipient on the additional (secondary) delivery, which is equivalent to a Bcc.
Select this option to deliver incoming messages to recipients even if the spam filter identifies these messages as spam.
Select this option to remove any attachments from messages. Optionally, you can append text to notify recipients that attachments were removed.
Check the Add more recipients box to set up additional, or secondary, deliveries for dual delivery or multiple delivery.
Select Basic from the drop-down list to add individual email addresses, and then click Save. You can add multiple recipient addresses by clicking Add.
Select Advanced from the drop-down list to choose advanced options for your secondary delivery. Similar to the settings that you modified for the primary delivery, you can change the envelope recipient, add headers, prepend a custom subject, and remove attachments for the secondary deliveries.
- A limit of 100 additional recipients applies for each rule. For this reason, consider using groups for large lists.
- Any settings that you configure for the primary delivery also affect the secondary deliveries. For example, if you change the envelope recipient, prepend a custom subject, and add custom headers to the primary delivery, the same configuration is applied to the secondary deliveries.
- For secondary deliveries, the Do not deliver spam to this recipient and Suppress bounces from this recipient boxes are checked by default. Suppress bounces from this recipient prevents bounces from going back to the original sender.
This option rejects the message before it reaches the intended recipient. You can enter customized text for the rejection notice.
Note: Any routing settings with this action specified are automatically placed at the top of the Default routing priority list. See Ordering your routing settings.
- In the Options section, choose whether to perform the action only on unrecognized addresses. You can also choose both recognized and unrecognized addresses.
Note: Suspended users are considered unrecognized users.
- Click Save.
- At the bottom, click Save.
It can take up to 24 hours to propagate changes to user accounts. You can track prior changes in the Admin console audit log.
The Default routing tab lets you configure multiple routing settings for your domain. Each routing setting specifies a recipient or recipients and an action to perform on any mail intended for the recipients.
Note: You can configure a maximum of 1000 default routing settings per domain.
The Default routing page displays a list of settings. To adjust a setting, click Edit. To delete the setting, highlight the check box in the left column, and click Delete. You can also adjust the order (or priority) of the settings on this page.
Important: G Suite applies all routing settings you specify to the affected inbound messages. If two settings conflict, G Suite applies the setting with the higher priority and ignores the lower-priority conflicting setting. However, any settings that specify Reject are automatically assigned the highest priority, even if you have assigned a higher priority number to another setting.
- To change the priority of a routing setting, click Reorder next to the setting.
- Enter the new number (for example, enter 1 to assign the highest priority).
- Click Save.
- Repeat these steps for assigning other priority numbers, such as 2 or 3.
For more details and instructions, see Email routing and delivery.