Golden Rule #1 gives what I consider to be the most basic security maxim, one on which I base all of my security practices, so let me repeat: The best security measures are completely useless if you invite attackers into your PCs or networks.
Windows users will remember back before Windows XP Service Pack 2 was released that simply plugging your computer into your cable or DSL modem was almost certain to result in your being compromised in short order. (Who can forget the havoc that Sasser and other worms wreaked before Microsoft wised up and finally turned the firewall on by default?) Running naked with all ports open to the world is a gold-gilt invitation to every criminal and mischief maker on the Internet, and while running a software firewall is a good idea, it’s not nearly enough–crackers have known for some time how to disable the Window’s firewall.
Consider this: every IP address owned and/or issued by your Internet Service Provider, no matter who that may be, is constantly being targeted by hackers that are scanning the’Net for vulnerable systems, and worms, viruses and other malware that have already infected machines on the ‘Net. (As I write this, the IP address assigned to me by my cable Internet provider has been scanned or probed 46 times in the last hour; this goes on 24 hours a day, seven days a week.) I certainly don’t want my PC’s software firewall subjected to this kind of thing. Yet, most people, not knowing any better, plug their computer directly into the broadband modem. There is absolutely no reason to do this when there is an inexpensive, simple, yet effective first line of defense available at any big box electronics or office supply superstore–a router (Fig. 1).
Through the beauty of Network Address Translation (NAT), even the cheapest router becomes an effective hardware firewall, virtually making your PC invisible to the ‘Net. NAT Router Security Solutions by Steve Gibson of “Security Now!” explains NAT in detail. Here’s one of his illustrations from that article:
I must mention that except for one, easy configuration change that is absolutely essential, these simple devices work fine right out of the box. The average user can plug it in and not have to worry about a complicated setup process.
Golden Rule #2: A first, important step in securing your PC is to install and configure a NAT router.