It appears that Alessandro Vesely <[email protected]> said: >> Is that a thing? A message with multiple "From"? >> >> https://www.rfc-editor.org/rfc/rfc6854.html
We beat this to death a few years ago. While it is possible to put two addresses in the From header, it is very uncommon, it is even less common to have two addreses in different domains, and the few examples I've seen are either mistakes or malicious. They are rare enough we can ignore them, messages with multiple From header domains can't be DKIM2 signed. >Wei convinced me that there must be at most one rt=, because, he said, the >official recipients, To: and Cc:, do not need to be repeated in rt=. They are >already signed and delivery to them is due. rt= is only needed for Bcc: and >forwards (which can be thought of as Bcc:). This way, there must be at most >one rt=, but there may be none. By far the most common scenario where the recipient isn't in the header is mailing lists. There will always be exactly one rt= because we don't allow more than one, and a mail delivery without an envelope recipient isn't a mail delivery. R's, John _______________________________________________ Ietf-dkim mailing list -- [email protected] To unsubscribe send an email to [email protected]
