Praetor is not a virus scanner in the traditional sense but can coexist with any virus scanning software to augment the AV technology you may already have installed.

Praetor provides an extra layer of antivirus protection by examining the message and its attachment declaration within the message header.   Praetor's rules can disallow reception of attachments containing *.EXE, *.VBS or any other file types which can commonly carry email-borne viruses.  There is then no need to AV scan such attachments.

Since Praetor's introduction in 1999, it has been completely effective against unknown viruses. Not one customer has ever had an infection get past Praetor.  All this without the need to install the virus pattern file updates  that are issued in response to a new viruses.