One particular class of spam that just won’t get filtered by SpamAssassin seems to be “newsletters” I’m getting in foreign languages, to the tune of ten or so a day.
The spammers are very kind, however, and send from email addresses almost always in Brazil. How might I instruct my server to simply reject ANY emails where the sender has a .br domain? Yes, I realize the implications here - on this server, I am comfortable doing such a solid block.
At which point would I want to configure this, and perhaps a pointer to how? At the MTA level and simply drop the mail on the floor? Or at the SMTP level and reject it with hopes that the sender stops trying?