Proposed authentication standard that is a merged proposal between the authors of SPF and Microsoft's Caller ID.

An authentication scheme, similar to SPF, sponsored by Microsoft. See "SPF."

Sender ID is an authentication protocol used to verify that the originating IP address is authorized to send email for the domain name declared in the visible "From" or "Sender" lines of the email message. Sender ID is used to prevent spoofing and to identify messages with visible domain names that have been forged.

Also known as TTI (Transmit Terminal Identification). This is the name (letter and/or numbers) entered into your fax unit to identify the company to a remote fax unit. The Sender ID prints out at the top of copies transmitted to other fax units.