RFC 2852 (rfc2852) - Page 2 of 13
Deliver By SMTP Service Extension
Alternative Format: Original Text Document
RFC 2852 Deliver By SMTP Service Extension June 2000 17:00. Another common usage arises when a sender wishes to be alerted to delivery delays. In this case, the sender can mark a message such that if it is not delivered within, say, 30 minutes, a "delayed" DSN is generated but delivery attempts are nonetheless continued. In this case the sender has been allowed to express a preference for when they would like to learn of delivery problems. 1. Definitions Throughout this document, the term "deliver" is taken to mean the act of transmitting a message to its "final" destination by a message transport agent (MTA). Usually, but not always, this means storing or otherwise handing off the message to the recipient's mailbox. Thus, an MTA which accepts a message to be delivered within a specified time period is agreeing to store or handoff the message to the recipient's mailbox within the specified time period. Outside the scope of the term "deliver" are any user-specified actions which might take place after the MTA stores or hands off the message; e.g., user-programmed filters which, often unbeknownst to the MTA, resend the message to some other location. The key words "MUST", "MUST NOT", "SHOULD" and "SHOULD NOT" in this document are to be interpreted as described in RFC 2119 [7]. 2. Framework for the Deliver By SMTP service extension The Deliver By SMTP service extension uses the SMTP service extension mechanism described in [4]. The following SMTP service extension is therefore defined: (1) The name of the SMTP service extension is "Deliver By". (2) The EHLO keyword value associated with this service extension is "DELIVERBY". (3) One optional parameter is allowed with this EHLO keyword value. The optional parameter, when supplied, is a comma separated list of options. Only one option, a min-by-time, is specified in this document. Future documents may extend this specification by specifying additional options. The min-by-time is a fixed integer indicating the fixed minimum by-time that the server will accept when a by-mode of "R" is specified as per Section 4. The syntax of the optional parameter is as follows, using the augmented BNF notation of RFC 2234 [2]: Newman Standards Track



