On Tue, Dec 17, 2019 at 01:49:00AM +0100, Ralph Seichter wrote:
> * Tom Blackwood:
>
> > In the outgoing message, what does "sender:" header stand for?
>
> https://tools.ietf.org/html/rfc2822#section-3.6.2
These days one should quote 5322 instead, but perhaps a more readable
discussion of email architecture concepts can be found in RFC5598,
and this case specifically:
https://tools.ietf.org/html/rfc5598#section-4.1.4
RFC5322.Sender: Set by - Originator
This field specifies the address responsible for submitting the
message to the transfer service. This field can be omitted if it
contains the same address as RFC5322.From. However, omitting this
field does not mean that no Sender is specified; it means that
that header field is virtual and that the address in the From:
field is to be used.
Specification of the notifications Return Addresses, which are
contained in RFC5321.MailFrom, is made by the RFC5322.Sender.
Typically, the Return address is the same as the Sender address.
However, some usage scenarios require it to be different.
--
Viktor.
