What is the Sender Authentication Package (SAP) and what components does it include?

The Sender Authentication Package (SAP) is a premium add-on that bundles several authentication and branding features into a single configuration:
1. Private (Custom) Domain: A dedicated sending domain (e.g., email.yourcompany.com) instead of the default @exacttarget.com or shared domain. Required for DKIM alignment with your From domain.
2. Dedicated IP Address: An IP address reserved exclusively for your sends. Provides control over IP reputation.
3. Sender Authentication: Configures SPF and DKIM records on your private domain so emails pass authentication checks aligned to your From domain.
4. Reply Mail Management (RMM): Processes replies and out-of-office messages sent to the reply-to address; can forward replies, trigger automatic unsubscribes on reply keywords, and suppress auto-replies from being counted.
5. Custom Tracking Domain: Click and open tracking links use your private domain (e.g., click.email.yourcompany.com) instead of Salesforce domains — improving deliverability and brand trust.