FBL Basics

Our FBL is keyed to the IP address of the server sending mail to our customers, not to the sending domain of any message. When we say "sending mail to our customers", we are referring to the server that connects to our inbound servers as part of the SMTP transaction; some might refer to this as the "peer server" or "connecting MTA" in the transaction.

What this means for you as a sender is that any data we provide you as part of an FBL enrollment will pertain to all mail from that IP address; if the server in question is a shared server (meaning one that sends mail on behalf of multiple domains) then the application for enrollment should be submitted by the organization that owns the server, and not by someone who owns/uses one of the domains on that server.