Megaphat Philter - Megaphat Philter is a server-side gateway that blocks unsolicited bulk e-mail (UCE, aka spam e-mail) using DNSBL technology. Unlimited DNS-BL databases, Reverse host lookup, alt-RR Lookup, MTA resolution, local blocking cache, dynamic DNS server caching, and so much more! Philter has real-time monitoring and a detailed report generating tool that lets you view all attempts to send mail from your SMTP server.