Once you create the content compliance rules, you must set up the routing rules to configure SMTP relay service. This ensures that you receive emails only from Nightfall's trusted IP addresses.
In the Nightfall UI, navigate to Integrations from the left navigation bar and click the Manage button for the Gmail integration.
All the headers and expressions required to create the compliance rules are available in the Installation section under Gmail settings as displayed in the image below. Keep this screen open to copy/paste the headers as you create the routing rules in Google Workspace. We will refer to this page as the Gmail settings page throughout the document.
To configure routing rules:
Login to your Google Workspace with an admin account.
Navigate to the admin console.
From the left menu, expand Apps > Google Workspace > Gmail.
Scroll down and select Routing.
Scroll down to the SMTP relay service section and click ADD ANOTHER RULE (the button can be displayed as CONFIGURE if you have not created any SMTP rules).
Enter a name for the SMTP rule (the name"Routing" is used in this case).
Select the Only accept mail from the specified IP addresses check box.
Click ADD.
In the Add Setting dialog box, enter a description in the Description field ("Nightfall IP" is used in this case).
Navigate to the Gmail settings page on the Nightfall UI and copy the value from the IP Address 1 field, located under the Routing - SMTP Relay Service section.
Return to the Google Admin Workspace window and paste the copied value in the Enter IP address/range field.
Click SAVE.
The IP address is added as shown in the following image.
Repeat steps 8-12 to add the other two Nightfall IP addresses (In step 10, copy the values under IP address 2 and IP address 3 fields).
Select the Require TLS encryption check box.
Click SAVE.
