On Thu, Feb 21, 2013 at 6:53 AM, Cyborg <[email protected]> wrote: > This seems to be a design issue :
It's not an exim design issue. It is a design issue of the SMTP protocol. Once you get to the data phase of an smtp email delivery, you are only allowed to issue one answer for all intended recipients: accept, reject, or defer. > Too inform the sender, that his attempt did not work, we have to reject it > on SMTP level, means inside acl_check_data or a similar capable acl. > Otherwise, we have to create a new delivery message and inform the sender > about the "later" failure inside a router. Which will not work with spams as > of the nature of most faked sender addresses. Correct, it's called backscatter. > a new acl "acl_per_recipient" could solve such problems on an elegant way. An experimental proposed SMTP protocol called PRDR (Per Recipient Data Responses) from several years back is exactly what you describe. It just so happens that Jeremy Harris and I coded up some experimental PRDR support and have merged it into the master development branch (which leads to the next release of Exim, whenever that turns out to be). It is sparsely tested, but I am running the code on a production server and it has not blown up yet, though I'm not really using the PRDR acl for anything that the DATA acl doesn't already do. If you want to test it, you can checkout master, build, install, and run it. If you happen to run exim on a CentOS 5.x machine that is not plesk or cpanel, I can put up for download on my personal website the rpms that I built and use in production. My build also has experimental DMARC enabled, which means that libopendmarc must be installed, which I also have available for download from my personal website. ...Todd -- The total budget at all receivers for solving senders' problems is $0. If you want them to accept your mail and manage it the way you want, send it the way the spec says to. --John Levine -- ## 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/
