SMTP Service Extension for Message Size Declaration
This memo defines an extension to the SMTP service whereby an SMTP client and server may interact to give the server an opportunity to decline to accept a message (perhaps temporarily) based on the client's estimate of the message size. [STANDARDS-TRACK]
Replaces RFC 1427: SMTP Service Extension for Message Size Declaration, RFC 1653: SMTP Service Extension for Message Size Declaration.
Normative requirements
Every sentence in this RFC carrying an RFC 2119 keyword, with the section it came from. 1 must, 0 should, 0 may.
6 The extended MAIL command
- MUST NOTNOTE: Servers MUST NOT use the SIZE parameter to determine end of content in the DATA command.