RFC 1426 (rfc1426) - Page 2 of 6

SMTP Service Extension for 8bit-MIMEtransport

RFC 1426                SMTP 8bit-MIMEtransport            February 1993


          (1)  the name of the SMTP service extension defined here is
               8bit-MIMEtransport;

          (2)  the EHLO keyword value associated with the extension is
               8BITMIME;

          (3)  no parameter is used with the 8BITMIME EHLO keyword;

          (4)  one optional parameter using the keyword BODY is added to
               the MAIL FROM command.  The value associated with this
               parameter is a keyword indicating whether a 7bit message
               (in strict compliance with [1]) or a MIME message (in
               strict compliance with [3]) with arbitrary octet content
               is being sent. The syntax of the value is as follows,
               using the ABNF notation of [2]:

                    body-value ::= "7BIT" / "8BITMIME"

          (5)  no additional SMTP verbs are defined by this extension;
               and,

          (6)  the next section specifies how support for the extension
               affects the behavior of a server and client SMTP.

4.  The 8bit-MIMEtransport service extension

   When a client SMTP wishes to submit (using the MAIL command) a
   content body consisting of a MIME message containing arbitrary
   octet-aligned material, it first issues the EHLO command to the
   server SMTP. If the server SMTP responds with code 250 to the EHLO
   command, and the response includes the EHLO keyword value 8BITMIME,
   then the server SMTP is indicating that it supports the extended MAIL
   command and will accept MIME messages containing arbitrary octet-
   aligned material.

   The extended MAIL command is issued by a client SMTP when it wishes
   to transmit a content body consisting of a MIME message containing
   arbitrary octet-aligned material. The syntax for this command is
   identical to the MAIL command in [1], except that a BODY parameter
   must appear after the address.

   The complete syntax of this extended command is defined in [5]. The
   esmtp-keyword is BODY and the syntax for esmtp-value is given by the
   syntax for body-value shown above.

   The value associated with the BODY parameter indicates whether the
   content body which will be passed using the DATA command consists of
   a MIME message containing some arbitrary octet-aligned material



Klensin, Freed, Rose, Stefferud & Crocker