
Deerfield.com's VisNetic MailPermit represents a comprehensive new approach to spam prevention, combining SpamAssasin's™ advanced rules-based and Bayesian filtering technology with a proprietary challenge-response system to create a powerful barrier between your business and costly, time-consuming spam..
Upon receipt of each email, VisNetic MailPermit verifies that the intended recipient is a valid user on the mail server. If the recipient is not a valid user, the email is rejected. The From address on email sent to valid users is subsequently verified against whitelists and blacklists established in VisNetic MailPermit, starting with lists defined at the agent level, then domain and system level. Mail from whitelisted addresses is forwarded directly to the mail server. Mail from blacklisted addresses is deleted.
Upon receipt of each email, VisNetic MailPermit verifies that the intended recipient is a valid user on the mail server. If the recipient is not a valid user, the email is rejected. The From address on email sent to valid users is subsequently verified against whitelists and blacklists established in VisNetic MailPermit, starting with lists defined at the agent level, then domain and system level. Mail from whitelisted addresses is forwarded directly to the mail server. Mail from blacklisted addresses is deleted.

VisNetic MailPermit 1.1 was released by Deerfield.com on Saturday 27 December 2003. Its known requirements are : http://www.deerfield.com/products/visnetic-mailpermit/requirements/.
VisNetic MailPermit will run on Windows 2000, Windows NT and Windows XP.