On 2012-03-11, at 8:39 PM, Ken Hornstein wrote: > My thinking was that since bounces go to the SMTP envelope-from, > bounces should go back to the person who wrote the message. In the > example above, I'd want to know about a bounced email, rather than > my secretary (I guess I could see other people NOT wanting to deal > with that, though). But since it's not obvious what to use when > there are multiple addresses in From:, Sender: should be the one > that should be used. But since I could imagine wanting to override > that, that's why I created Envelope-From:.
The intent for Sender: is that it represent the entity responsible for the transmission and delivery of the message, and that explicitly includes handling DSNs, therefore the Sender: address should always be used as the MAIL FROM address, if it's present. But even in the presence of Sender:, the Envelope-From: should override Sender: to allow for the scenario where [email protected] sends a message on behalf of [email protected], but wants DSNs directed at [email protected]. E.g.: From: [email protected] Sender: [email protected] Envelope-From: [email protected] This makes it clear that grunt initiated the message on behalf of boss while allowing grunt to point DSNs at a filter that automatically processes those DSNs. Thus the MAIL FROM construction logic would be: * use envelope-from, if present * use sender:, if present * if multiple from: and no sender:, abort * use from: address But there is another issue that we need to address. Envelope-From: is a valid message header. It's remotely conceivable that someone might have a need to use it for another purpose. And there are other SMTP parameters that it might be useful to set, e.g.: deliver-by. I don't like the idea of co-opting yet more headers out of the 822 namespace for this. I would prefer to build these non-822 directives using a syntax that can't be confused with a valid 822 header. I suggest the format: metahead = "." directive *(SP params) directive = LETTER *(LETTER / DIGIT / "-") params = ; free-form text to the end of line In the new syntax the above example would be written as: From: [email protected] Sender: [email protected] .mail-from [email protected] Post would strip out all the .foo meta-headers. Since these headers will be specific to the backend transport I would suggest ignoring ones unknown to the backend, and giving the backend the ability to print warnings, or abort the send, if there are problems processing a recognized directive. --lyndon _______________________________________________ Nmh-workers mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/nmh-workers
