Matt Fellenz

This is how it's done in gmail: https://www.lifewire.com/send-a-reply-and-archive-with-one-click-in-gmail-1172119 And it's a send option in fairemail:

It's in firefox. The Content-Type is correctly set to application/pdf. I think it's just missing the Content-Disposition to make it inline content instead of an attachment.

Also, if you change it from iframe to embed it works. I'll make a PR for that.

I can still reproduce in firefox, but not in chromium. Patch made no difference.

In my most recent testing none of the PDFs I tried caused a download. I still don't know what's causing it.

> only some hop headers [...] possibly dkim. > Use address B. This would cause C to evaluate spf to "pass", but may cause dmarc to evaluate to "fail" at...

Hm, I see your points and I agree that it's problematic that B becomes responsible for retrying sends to C. So maybe online forwarding is indeed the best way to...

Oh also I want to add that Outlook does forwarding wrong and messes up DKIM. So we can use it as a reference of how not to do forwarding :)

> And so actually C should be configured in a way that doesn't do IP checking against B. Maybe, but would there be an issue with C checking B anyway?...

> Another thing to consider is this forwarding scenario: A→B→C→D. [...] This is an argument to not apply sender rewriting at B. To me it seems more like an argument...