ORF Enterprise Edition 

ORF Enterprise Edition is an enterprise-level anti-spam solution that helps you to block spam before it reaches your network. ORF uses a combination of anti-spam technologies to stop the spam on SMTP protocol level.
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mxORB 

mxORB is a server-side spam filter that consistently blocks over 98% of unsolicited commercial email (also known as spam) at a fraction of the cost of other filtering solutions.
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PostGuard Spam Filter 

Sentinare PostGuard - Secure encrypted spam and virus free email for your home or business. 99% accurate filtering solution includes 1GB of email storage that will never be subjected to email marketing or advertisements. Your privacy, our priority.
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