Of course, as businesses give their employees Internet access, the chances of a virus finding its way to your network multiply. Not surprisingly, email is the leading method of virus transmission. And that s what we saw with Melissa. While most administrators are diligent about protecting file servers and desktop clients, they often leave Internet connections unprotected and hope the firewall will keep them safe. Unfortunately, firewalls care only about where a file came from, not what it contains, making them poorly equipped to cope with viruses.
Different servers require different types of protection.
HTTP is the carrier for ActiveX controls and Java applets, which could contain viruses that must be removed before they reach the browser. To protect email, the products must open up each database and look for any hidden viruses attached to the message before the recipient reads it or forwards it to others. And FTP is a perfect way to download applications that could be laced with a virus. Products such as Trend Micro's InterScan VirusWall, Symantec Corp.'s Norton AntiVirus for Firewalls and Networks Associates' WebShield address all these threats by scanning all packets coming in from the Internet. Most run on Windows NT, but some are also available for Sun Solaris.