Dovecot Proxy and Director

Hi, just a simple question: by using a directory and a proxy, I would be able to totally hide the pop3/imap server ip addresses from outside? I'm asking this because I would like to hide the real server IP for security reasosn (DDoS and so on).

The proxy would be placed on servers with high bandwidth while the pop3/imap dovecot servers are placed in a small datacenter that would go down easily in case of attack