Gateway AV

Stopping viruses should be a three-tiered approach.  The first should be a server based anti-virus check for all inbound email, before it gets in to your network.  The next virus check should be at your internet "gateway," before the traffic passes from the internet into the network.  The last check should be at each user's desktop.  Combating viruses at each of these three check-points is critical. 

You see, viruses not only hide inside of email, they also hide inside of websites and downloads.  The Gateway AV check will look at various types of inbound traffic, and check for viruses.

Gateway AV