Q. "My LAN consists of two home computers with Netgear cards in each. Both computers have Win98 Second Edition and Internet Explorer 5.5, and they share one modem and a printer. This works well. Norton Antivirus is installed on one machine. Are both machines protected through the network, or should I install this program separately on each machine?"

More Questions • Complete FAQ List    Join the Discussion "I plan to network my Windows XP computer with a Windows 98 computer at home, using network cards, a hub and CAT5 cable. I use a modem dial-up for Internet connection. If I enable Internet sharing, can I set it up so the XP machine is the only one that needs the firewall and virus protection? If the Win98 computer accesses the Internet and email via the WinXP computer, will the WinXP computer take care of all the Internet security for both?" -SUNFIRETERVS     Related Resources • Top Personal Firewall Software • Top Broadband Routers • Proxy Servers and You • Network Security Resources

... . Some computer viruses spread through files copied from floppies rather than through the network. Maintaining an antivirus program on each computer increases the likelihood of preventing this. When using Microsoft ICS or a proxy server, it is also possible for a person to download files from the Internet directly to any client computer on the home LAN. Even though the file's contents pass through the server's network interface, these downloads generally won't trigger the server's antivirus program because the data appears in the form of network data packets, not actual files that can be scanned. With antivirus software on each client, these downloads can be monitored.

Now consider firewall software. By definition, a firewall guards the boundary between a local area network and the "outside" world. Therefore, firewalls need only be installed on the home computer(s) that have direct access to the Internet connection (the phone line, cable line or satellite link, for example).

Today's broadband routers contain built-in firewall support as part of the hardware package. It's common for home networkers to wonder whether they need personal firewall software in addition to router hardware. Unless quality problems exist with the router, additional software is generally unnecessary. However, some networkers prefer to install a software firewall on each computer anyway. If having multiple firewalls increases a person's confidence in the security of their home network, that's reason enough to have them. Note, though, that installing more than one software firewall on the same computer is generally not recommended; some of these programs do not interoperate with each other.

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