we all just want a clean inbox

Ah, but we also want to retain the ability to receive legit mail from anyone, even people we've never got mail from before. (I have content on my personal website about puppetry, and about constructing puppet stages. I receive email from arbitrary people who found it in a web search, and wanted additional info about a particular facet of it, on a semi-regular basis. I don't want to make these people jump through extra hoops (web-based "mail" forms and similar) to contact me. Also I maintain a usenet FAQ (though I get fewer questions about that since it's an obscure one). Also, it seems wrong to penalize legitimate people who want to contact me, because of the abuses of a few utter losers.

Still, if it was relied on strictly enough by a significant enough portion of the internet, the pressure to get your RMX RR right or perish would be significant. Even if only the large mail hubs (Hotmail, Yahoo and the many other freemailers) which are frequently used as forged senders implemented this (on both directions, their own RMX RR as well as requiring them from senders) that would be a step forward.

You're daydreaming. The chances of a major ISP of any kind agreeing to reject possibly legitimate incomming mail because it doesn't comply with some new standard are roughly the same as the chances of Microsoft releasing the complete source code for the current version of Office under the BSD license, or Macromedia producing a useful piece of software.

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