Thanks Viktor. That make thing clear. On Tuesday, December 17, 2019, Viktor Dukhovni <postfix-us...@dukhovni.org> wrote:
> 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. >
