Anti-spam SMTP mods

[Lucas Peet]

David Nicol wrote:
> Problem two:  Assuming that SMTP requires all participating peers to 
> sign themselves, how
> does that help arbitrate and filter?  Fine, upstanding direct marketers 
> will still be sending you
> advertisements for keywords that if mentioned would get this message 
> filed as junk, but now
> from an authenticated server.

Because there is no authentication.  And yes, spammers & direct 
marketers will still be trying to send signed messages that can be 
verified where it came from, but those originations can be easily 
blacklisted. Also, if like I had mentioned, if a rating system was 
implemented at the same time, spam / marketing hosts, because they send 
off so much spam, fewer hosts will sign them, because they get spam from 
them.  This goes back to the PGP trust method - check them out, when 
you're 100% sure of their identity, *then* sign their key.  If they have 
a particularly low spam-to-real email ratio, they'll get a higher rating.

So the servers that are known to *not* send spam will have more 
signatures, giving them a higher rating than a server that is *known* to 
send spam, which will have fewer signatures, and thus a lower rating. 
And only valid, verified and previously signed signatures can sign 
others, like you need 2 (or 3?) signatures on your PGP key to be able to 
sign another with any kind of authority.

-Lucas