I've been doing something similar for a good long time. Blogged about it here: https://www.spamresource.com/2015/12/mail-forwarding-in-dmarc-world.html The current version of my forwarding script rewrites the from address, disables the authentication headers (re-authenticating the message anew upon sending), rewrites the message ID (which I found to be very handy if you want to re-forward the same message more than once, either in testing or in real life) and I usually drop the original sender's address both into a hidden x-header and the reply-to header.
Cheers, Al Iverson On Wed, Jan 11, 2023 at 2:53 AM Hans-Martin Mosner via mailop <[email protected]> wrote: > > I've written something like that a while ago. It's in Rust, it's probably too > specialized and restricted for general use, but it does mostly what you > describe (in addition, it keeps sender addresses secret becaue I've > encountered too many cases of hacked e-mail accounts where address books have > been exfiltated). > I chose Rust because, well, I'm doing much of my side project hacking in Rust > nowadays, and it creates stand-alone binaries which simplifies deployment on > arbitrary Linux servers. The data is held in a simple sqlite database, and > the binary serves both as the actual forwarding filter as well as database > management tool, so it's somewhat scriptable. > I could clean it up a bit and put int into my github account, but as I said, > it's probably not general enough and would need some polishing before being > ready for public consumption. > > Cheers, > Hans-Martin > > 10. Januar 2023 22:59, "Dan Mahoney via mailop" <[email protected]> schrieb: > > > All, > > > > Sometimes a problem comes across your desk that you say “wait, how is this > > not solved yet?”. > > > > At the day job, we have a contact list for our customers that comes from > > our ticket system, and > > it’s stuffed into an alias file with :include:. > > > > The way postfix handles these aliases, is that it preserves the original > > envelope sender and > > recipient (which we don’t want anyway), and o365 is rejecting on that > > envelope sender/recipient > > (that it’s not allowed to deliver to our internal envelope recipient, which > > is not unreasonable, > > but still surprising we haven’t hit it before. > > > > The obvious answer is: “Don’t use the :include: mechanism, just use a > > mailing list manager.” Which, > > for one alias in a system, feels like overkill. I don’t need membership > > management. I don’t need > > archiving. I don’t need bounce detection. > > > > So I’ve gone down the rabbit hole, looking for various combinations of > > remailer scripts, forwarder > > scripts, group forwarder scripts, mailing list expanders, etc. And I’m > > coming up surprisingly > > short. > > > > Could I knock something together myself in perl in a half hour? Sure. > > > > Would it likely have its own untested edge cases for us to discover? > > Absolutely. > > > > In a world of DKIM/DMarc compliance, especially, where “blow away the > > original headers and forward > > anew” is the best answer, I’m shocked to not find something like this as > > well. > > > > Our needs are simple: a unix program we can pipe a message to that will > > preserve the original > > message mime portions and subject, but discard most of the previous other > > headers. How in 30 years > > of email, something that I can’t just pkg install isn’t easily findable > > baffles me. > > > > If someone knows of something, let me know. > > > > -Dan > > _______________________________________________ > > mailop mailing list > > [email protected] > > https://list.mailop.org/listinfo/mailop > _______________________________________________ > mailop mailing list > [email protected] > https://list.mailop.org/listinfo/mailop -- Al Iverson / Deliverability blogging at www.spamresource.com Subscribe to the weekly newsletter at wombatmail.com/sr.cgi DNS Tools at xnnd.com / (312) 725-0130 / Chicago (Central Time) _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop
