[enhancement]: Prevent mailbox recipient bruteforcing

[ghagl]

Which feature or improvement would you like to request?

I would like to block spamhosts who repetitively try to e-mail (non-existent) mailboxes

Is your feature request related to a problem?

No response

Code of Conduct

• [X] I agree to follow this project's Code of Conduct

[williamdes]

I would like to block spamhosts who repetitively try to e-mail (non-existent) mailboxes

Can we have a system that does some of the following:

• Be very slow to reply to login for not known IPs ? (like a greylist)
• Add successful logins to a list and skip the slowness for next logins
• Have a code hook that users can implement and add a middleware to do the following: check if the IP is on a block list or check the country of the IP. And the reject the login.

Having a middleware/hook would be great so it can be easy to deny the login attempt before it is computed. Country of the IP check, you know China bots... -> Denied Reverse DNS -> Matches some name -> Denied AS owning the IP -> China net -> Denied

You get the idea