I have a question, more so probably an idea.
We are using Smarter mail 14. Can 15, 16 or 17 do this ? Or if not, can it be implemented ?
We have various EHLO SMTP blocking set up (*.date, *.top, *.ninja) In total we have about 50 of them blocked as they are pretty much guaranteed spam.
I would also LOVE to block *.us as the bulk of it is spam, since places like Godaddy are selling .us domains for 99 cents each, this is cost effected for spammers to buy these domains up as burners
However, about 10% of the .us email coming in is legitimate.
What i would love to do is :
1) set up SMTP EHLO blocking (graylisting ?) on *.us domains,
2) and then tell smartermail if an email comes in from a *.us domain, to have smartermail send an email back to the sender requesting whitelist status or requesting a send verification. something like
--- Notice : You are sending from a domain that has been flagged on our servers as a potential spammer, Please click this link below and answer the captcha to verify this is a legitimate email contact.
3) If you get a legit authentication response (or maybe 2 or 3), then it could white list or flag that domain so it does not consider it as a blocked one any more.
This way we could block the vast amount of garbage and still let the legitimate email come in.