That is all. I made up that last part. It also knew the Media Access Control address of my network card and the name my computer uses to identify itself on a network. All such information could be used by an unwanted intruder to gain access to my machine or target it for a later attack. Gibson said there are basic precautions computer users should take to improve the security of their machines.
Nobody can use the Internet to break into a computer that's turned off.
As the name implies, these programs put up an electronic barrier between your computer and the Internet. Some are better than others. But the general idea is to block any online traffic to and from your machine unless you've authorized it. Firewall programs shouldn't be confused with anti-virus software. The latter is used to detect and delete electronic viruses that might be hiding within files that find their way into your computer.