MIT's server limits the sending of unauthenticated mail to 1000 non-MIT recipient addresses per sending address, per day. The particular SMTP server used may either disallow or place limits on the sending of unauthenticated mail.

When sending email using an SMTP server, you have the option of authenticating or not authenticating. Sending email via SMTP server can be a useful option in that the user doesn't have to leave the FileMaker application during the process of generating email, and it eliminates any potential differences in behavior between the various email clients and how FileMaker interacts with them.

There are two native methods for sending email from FileMaker: via the user's default email client, and via an SMTP (simple mail transfer protocol) server.