what does block mail mean? Is the mail then silently dropped
I dont like silently blocking either. I'd be more interessted in rejecting since the sender gets informed. I cant use block for content that could be false-positives.
if i reject a mail the server whos trying to deliver a mail would just see the reject and would act on it. If its a spammer he probably wouldn't do anything at all. If its a "real" Mail the sender would act on the rejected reason.
Most of the time, will do a lot of actions, like:
- send again, but with a modifiied message(so on the next try his message will be not rejected)
- inform others spammers that your mail address is valid, and could be used
So if you want to have a low spam rate(and not others reasons), the best thing is to REJECT with a nice message like this:
REJECT 554 5.1.1 Recipient address rejected: User unknow
@Spanguel Be careful with automated answers, as @dietmar wrote, it's a very bad idea, you act as a backscatterer then and may get blocked. So that's why I asked for a reject. The current code base with spamassassin "alone" is not able to handle that, maybe Proxmox will change to amavisd(-new) or rspamd, then it would be possible.
If you think that silently dropping is not legal in your country, just do not use block rules.