When you use an inbound mail gateway, the MX records for your domain point to the inbound
mail gateway server. You configure the gateway server to pass the incoming mail on to the
Google Apps mail servers, and configure the Google Apps mail servers to accept a stream of
incoming mail from the gateway server.
To configure an inbound mail gateway:
1. Update your domain's MX records so that the highest priority record refers to the inbound
mail gateway server.
See Creating MX records for detailed instructions.
2. Configure the inbound mail gateway server to deliver mail to the Google Apps mail
servers.
The configuration steps differ depending on the gateway server.
3. Sign in to your Google Apps administrator control panel.
4. From the menu at the top of the page, select the Settings tab.
5. From the left-navigation menu, click Email.
6. From the Email settings page, click General Settings.
7. In the Organizations section at the top of the page, highlight your domain.
8. In the Inbound gateway box, enter the IP address of the inbound mail gateway server.
If you have more than one gateway server, enter an IP range in CIDR notation or separate
each IP address with a comma. If you are using the Postini Services, include the
addresses of the Postini servers:
64.18.0.0/20,207.126.144.0/20,74.125.148.0/22,74.125.244.0/22
9. Select the check box Only let my users receive email from the email gateways listed
above.
This setting ensures that all incoming email comes through the inbound gateway server
and is therefore properly filtered or archived. The Google Apps mail servers will reject
incoming mail from any other mail server.
10. Click Save changes at the bottom of the Email settings page.
11. Verify that incoming mail is properly delivered.
Once your MX record changes from step 1 have taken effect (that is, after the previous
MX record's TTL has expired), send an email message to a user in your domain. Confirm