As is the case with all conveniences, there is a trade-off for the speed and ease of connection that comes with a constantly-on, high-speed Internet connection. Since your computer or computers always have the Internet available to them, that means they are constantly exposed to the Internet. It is probably not news to you that the Internet can be a very unsafe place - but this need not be the case.
A few simple safeguards can restore security to your Internet connection without affecting performance. The first element is already built into devices like the Linksys Router shown on the previous page. It is called a Network Address Translation (NAT) Firewall. This is simply a technique which uses "local" addresses for your machines behind the firewall (addresses that don't exist and are not valid out on the Internet) and keeps them from being revealed in interactions with Internet servers. When servers ask the router what its address is, it replies with the address assigned to you by your Internet Service Provider. Anyone can know this address without fear, because there is no computer on your network that resides at that address. All your computers have local addresses that no one else knows. The router does all the dirty work of translating incoming and outgoing requests to the proper addresses and everyone is happy and secure.
While this method is robust, no security system is completely fool-proof. Even though there may be no known way to defeat a given technology today, someone might discover or dream up a way tomorrow. So, that's why we recommend a second security system - firewall software to supplement the firewall in the router.
There are several software firewall solutions on the market, but ZoneAlarm® from ZoneLabs, one of the most well-respected, is actually free for personal use. The paid version of ZoneAlarm®, suitable for business use, is an excellent way to secure and monitor all connections and access to and from your computer.
If you want to see just how effective the NAT firewall in a typical router is, simply remove the router and hook up your PC directly to your broadband modem, then start up the ZoneAlarm® software. Now you can watch all the alerts generated by (unsolicited!) attempts to connect to your PC from the Internet. Virtually all of these connection attempts would be filtered out when you run ZoneAlarm® behind the NAT firewall in a router.
Visit the ZoneLabs web site for more product information on ZoneAlarm®.