SonicWALL Network Anti-Virus is a subscription-based upgrade for SonicWALL's family of Internet security appliances. Network Anti-Virus ensures that the entire network is constantly protected from virus attacks. The SonicWALL Internet security appliance enforces the use of up-to-date anti-virus software on each protected computer to prevent users from disabling the software and risking infection. The anti-virus software is transparently and automatically deployed and maintained for each computer on the network, eliminating the need for desktop-by-desktop installation and maintenance. SonicWALL Network Anti-Virus also includes E-mail Attachment Filtering, which allows the network administrator to set up rules for filtering incoming E-mail.