Giampaolo Tomassoni wrote:
> Hi everybody,
>
> anyone knows of a SA plugin to score mails based on challenging the sender
> e-mail?
>
> I don't mean C/R, but instead just attempt an SMTP session in order to see
> if the source mailbox is known to the sending domain's MX. If it isn't, the
> plugin applies a score to the e-mail.
>
> I know I could do something like this in my postfix, but this way I would
> totally reject e-mails carrying a wrong From: header. Since some people seem
> to be a bit dyslectic in writing its own e-mail address, I would prefer not
> to reject unless there are some other reasons too (i.e.: the mail hits some
> other SA rules).



Doing it at the MTA is called "Sender Address Verification", and isn't
considered to be that much better than C/R (it doesn't clutter a
forged-sender's mail box, but it can bog down a forged-sender's mail
server with verification requests).

I wouldn't expect a sender verification plugin for SA to be any better
liked than doing it at the MTA level.