c) Create a connector1. A connector is a configuration setting that controls how email messages are delivered to or received from your own email servers or a partner organization1. You need to create a connector to route mail between Exchange Online and your on-premises alarm system that uses SMTP1. You can specify the IP address of your alarm system as a trusted sender and configure the connector to use certificate-based authentication or IP address-based authentication1.
e) Configure direct send2. Direct send is an option that allows you to send mail directly from your printer or application to Microsoft 365 or Office 365 without using a local email server2. You need to configure direct send on your alarm system settings to use an MX record of the tenant as the SMTP server address2. For example, contoso-com.mail.protection.outlook.com2. Direct send does not require TLS encryption or SMTP authentication2.