> From: jarek
> Is it possible, to configure exim, so it will drop/reject message
> processing after first "Unknown user" ?
> One of my servers is under permanent DDOS with thousands of clients
> trying to send messages to non existing recipients.
If the non-existing recipients are on your server then
in the rcpt ACL insert before "require verify = recipient":
drop domains = +local_domains
!verify = recipient
If the non-existing recipients are not on your server then
https://github.com/Exim/exim/wiki/BlockCracking
