On Wed, Jul 4, 2018 at 9:51 AM, Evgeniy Berdnikov via Exim-users < [email protected]> wrote:
> On Tue, Jul 03, 2018 at 06:46:25AM +0200, Jan Ingvoldstad via Exim-users > wrote: > > On Mon, Jul 2, 2018 at 6:40 PM, Bill Cole via Exim-users < > > [email protected]> wrote: > > > > > On 29 Jun 2018, at 15:30, David Cunningham via Exim-users wrote: > > > > > > > > >> I am using a smart host that will not accept emails from <>. > > >> > > > > > > Are you convinced that "smart" is the right word here? I'm quite > certain > > > it is not. Maybe you meant "grossly misconfigured outbound relay" > instead? > > > > > > I think another issue to keep in mind is that certain broken e-mail > clients > > also send messages with the empty envelope sender in response to spam. > "I'm > > on vacation", "This message has been read", "This message has been > deleted". > > The 2nd and 3d messages may be treated as Message Disposition > Notifications > (MDNs), and 1st message may be admittedly assigned to this cathegory too. > All MDNs must be sent from <> address, as RFC3798 says in p.3: > > The envelope sender address (i.e., SMTP MAIL FROM) of the MDN MUST be > null (<>), specifying that no Delivery Status Notification messages > or other messages indicating successful or unsuccessful delivery are > to be sent in response to an MDN. > > The most impotant reason to treat mentioned messages as MDNs, I think, is > the fact they SHOULD NOT be answered. If such message has user's envelope > address, autoreply or other MDN may be generated, forming mail loop. > > So, broken e-mail clients are those that put user's address to envelope > sender for MDNs, particularly Outlook and MS Exchange. > No, Outlook does not do this. Outlook is one of those who, brokenly, send MDNs, generating backscatter. Maybe MS Exchange can be configured to generate backscatter similarly, I don't know. -- Jan -- ## List details at https://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
