Filter mail on dns niveau

[snaaps]

I think,

maybe it's a good idea that users can select in the spam filter or spamasassin that they want to block mail that hasn't reverse dns, use a blacklist (spamcop) and other dns futures.

That way each user can select if they want to recieve mail that doesn't a good dns, c.q. can be seen as spam.

how to you think about this?

 

[nobaloney]

By the time email gets to either the filters or to SpamAssassin, it's already been accepted on the server and it's too late to block it. You can either discard it or deliver it. You can't return it because you have no idea who sent it (the username on spam is usually forged).

You can certainly add rules to SpamAssassin to filter on either of your criteria, and you can tell SpamAssassin to throw away the emails that are over a certain score. For example, add 100 points for no reverse DNS and 100 points for inclusion in (for example SpamCop, and then to throw away the email on scores over 99 points.

But for blocklists, you'd be much better off turning on SpamBlocker for the domain; SpamBlocker does block emails in blocklists.

Jeff