Use a Hosts File in Windows

Often times websites bombard you with advertisements when all you want to do is view the page. Other times you may accidentally download spyware from a harmful website. Sometimes you just need to block a webpage, either from a child or from a co-worker. A custom HOSTS file solves all of these problems.

The HOSTS file is a plain text file that you can edit (with system administrator privileges), or you can obtain a new extended HOSTS file which "blocks" (really redirects) various known ad sites. Note that you are a trusting soul if you do this without understanding and checking the contents of any file you use to replace a system file.

Steps

  1. Visit http://www.mvps.org/winhelp2002/hosts.htm and download the file "hosts.zip". Extract this zip file to your desktop.
  2. Next, locate your HOSTS file. The hosts file is located in different places depending on your Windows version. For XP it is located in the C:\WINDOWS\SYSTEM32\DRIVERS\ETC directory. For 2000 it is located in the C:\WINNT\SYSTEM32\DRIVERS\ETC or C:\WINDOWS\SYSTEM32\DRIVERS\ETC folder, depending on the nature of your Windows install.
  3. Copy the file "hosts" from the extracted zip file by right clicking on it and selecting "copy" and then paste it in the directory listed above. Windows will ask you if you wish to overwrite the existing file. Choose "Yes". Many advertising sites and known spyware sites are now being blocked.

Tips

  • To manually block a site, go to the bottom of the file and on a new line type "127.0.0.1 siteyouwanttoblock.com" without using quotes. This will block siteyouwanttoblock.com. Repeat the process for any other sites you wish to block, and then save the file by going to File>Save.
  • To view the contents of this file, browse to the location of the file and double click on it. For XP Users you will be asked whether you want to search the internet for a program to open the file or if you wish to choose from a list. Choose the list option and open the file with Notepad. You can now view all of the websites that are being blocked.
  • Click Start – search for “Notepad“, right-click and select “Run as Administrator“. This should launch notepad with elevated privileges. From Notepad, open the host file from the File menu, edit and save.
  • To unblock a site, find its line and put a "#" in front of the 127.0.0.1 for that line.
  • To edit the host file as an administrator:

Warnings

  • NEVER delete or comment out the first line of the file reading "127.0.0.1 localhost". This is normal and is needed by Windows.
  • If other PCs connect to the internet VIA your PC, such as pcs using Internet Connection Sharing, the HOSTS file will block websites not only on your PC, but on the other PCs as well. This is because the HOSTS file blocks all outgoing connection attempts by ANY PC to these harmful web sites.
  • On some pages, you may receive a "page not found" error on part of the page, usually in a square or rectangular box. This is normal and is part of the ad blocking process.
  • This file will block many common adware, spyware, and advertising sites. In some cases where you actually wish to view an advertisement it may be blocked, or may lead to an error page when clicked. This is most common when using Google Adwords or searching in Google. To view the site, simply type its full real url into the browser.
  • This file does not block all harmful websites, rather it blocks the most common known harmful sites. This file is not a cure-all and thus you should still execute caution when downloading files from the internet.
  • You can still visit websites you blocked with a web proxy. To completely block websites, you may need a professional website blocker.

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