SMTP Service Extensions for Transmission of Large and Binary MIME Messages
This memo defines two extensions to the SMTP service. The first extension enables a SMTP client and server to negotiate the use of an alternative to the DATA command, called "BDAT", for efficiently sending large MIME messages. The second extension takes advantage of the BDAT command to permit the negotiated sending of MIME messages that employ the binary transfer encoding. This document is intended to obsolete RFC 3030.