I have a user whose domain receives an ungodly amount of spam (one word domain name), and has opted to not use his mail at all because of it. This is great because he receives so much spam that it causes load spikes on the server.
I removed his MX record from DNS thinking that this would stop mail from coming to the server, but it seems that even after about a week, the messages were either still cached OR, they were just tracing to the IP of the server and flatout sending it too that IP (I know that sounds far fetched, but somehow they are still getting to the server).
My question, how do I prevent any and all mail for this domain from even hiting my server? I'd much rather not worry about his e-mail. Any suggestions?