rconner Posted September 8, 2007 Share Posted September 8, 2007 I normally post in the lounge, but this seemed like a more apporpriate board for this question. Admins may move it if they see fit. As I understand it, bounce messages sent by MTAs can be called "non-delivery reports" (NDRs) or "delivery status notifications" (DSNs). Apart from the fact that DSNs have their own MIME type and RFC (3464), plus an expanded set of reason codes (RFC 3463), what is the difference between the two terms (if any)? I get the impression that NDR is a rather generic term dating from original SMTP, while DSN refers to a message that follows the RFC and is of the appropriate MIME type, and might be associated with ESMTP. I also get the impression that you can get a DSN if your message is delayed (i.e., "We'll keep trying...") while the NDR implies by its name a final notice of non-delivery. Maybe NDR is an old-school term, to be replaced by DSN? Wikipedia was a bit ambiguous on the topic, and SMTP (RFC 2821) was not very explicit either. I'd appreciate any thoughts on the subject, as I'm presently writing a book (on spam) and would like to get these terms down correctly. -- rick (edited to add more descriptive subject line) Link to comment Share on other sites More sharing options...
This topic is now archived and is closed to further replies.