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Hi Jens,

Thanks for the really thorough answer!

On Sat, 29 Jan 2022 at 13:45, Jens John <lists@example.com> wrote:

Under SRS, the From: header contents stay constant while the envelope address is changing. I believe that's what you're looking for.

Yes, that sounds like what I want.

SRS is meant to be used with SPF.

I'm not sure how doable SPF would be with my current setup, but I can definitely look into it.

If email is not properly or not sufficiently "authenticated", hosts like Gmail will add to emails a "Via" note in the web UI, for example, "From: joshglover@example.com Via: tlug.jp" if the email came via tlug.jp but without an unbroken ARC to the email origin.

This is perfectly fine for my use case.

Your solution with the S3 and Lambda might be enough for your use case. However, if you want to do email "right" in your own implementation, be prepared to implement a partial SMTP server, and due to DKIM/SPF/DMARC/ARC, SMTP is not really "simple" anymore.

Haha, I've come to the same conclusion about the deprecation of "simple".

I am prepared to implement a partial SMTP server, as it sounds like a fun way to learn about some of this stuff.

If you want to explore further, I suggest you sign up with a good host like Fastmail for a month or three, send yourself some email and observe the raw messages, or peruse the Gmail raw message view more often for debugging.

I can see the raw incoming and outgoing messages with my lambdas, so I've been able to reverse engineer *some* stuff.

Thanks for all the pointers! This has given me a few avenues to explore during the coming weekends. ;)

Cheers,
Josh

Re: [tlug] Email forwarding