I've a mail server, which handle multiple domains. Due to concern of spam and mail server performance. I've configured another machine which will be in bridging and mail server would be behind that it.
How can i filter spam emails in bridging server without running any smtp services.
Internet +------+ Spamfilter Server (in bridging mode) +---------+ MailServer
SmartHost will work for outgoing email. In this scenario i can filter all incoming emails. There is also another option of DNS which i don't want to use.