A "hosts" file is a list of sites your computer is not allowed to connect to. A PAC (Proxy Access Control) file is a set of rules defining what type of content your web browser is not allowed to view. When used together, these files act like a wall, blocking where your computer is allowed to go on the Internet. By using a pseudo HTTP Daemon (a specialized web server), your web browser never even realizes it's being blocked.
A Leash for your Computer
So you think your computer is secure? Think again! Let us tell you why it is not.
The Internet is full of places you don't want your computer wandering into. Sites that install spyware, adware, viruses, mass-mailers, and worse. Many of these bad sites are well-known to Internet security researchers. Nothing on your computer should be allowed to connect to these known bad sites. Other sites are more of an annoyance. These are sites that slow your web browser down with advertisements or try to track everywhere you go on the web. Then there are hate, gambling, pornography and other "adult" sites. You might think these types of sites are fine if you're an adult, but these sites are often used as launching platforms for programs that are aimed at taking control of your computer.
Unfortunately, your computer will go anywhere it's told. Every time you do an innocent web search, you risk going to a new web page that will tell your computer to go to a half-dozen other web sites to get images, scripts, style sheets, cookies, movies, or controls. Maybe the site you originally went to is okay, but what about the other half-dozen your computer just went to without your knowledge?
You need a leash for your computer! Your existing anti-virus and anti-spyware software will have a much better chance of handling threats if yoiu can stop your computer from automatically wandering into the high-risk areas of the Internet.
All downloads on this site for both Unix and Windows systems use both 7zip (*.7z) and Zip (*.zip) format compression. The wonderful GPL 7-Zip program is available here: 7-Zip Program