Using the Hosts File to Block Content

Your Hosts file is an important system file for network communications, and it can be used as a rudimentary method for blocking Internet sites. Given the fact that the IP address 127.0.0.1 always points to your local computer, you can modify your Hosts file so that a website that you want blocked is mapped to that IP address.

Say that you wanted to block "www.facebook.com". Modify your Hosts file so that it contains this line:

127.0.0.1     www.facebook.com

Now if you direct your Web browser to "www.facebook.com" you will instead be directed back to your local computer. The reason this happens is that in parsing the domain name (www.facebook.com) your computer looks to the Hosts file for resolving the DNS address instead of to an external system which would return the real IP address for Facebook.

The ability to use a Hosts file has led some folks to develop rather complete blocking solutions for individual computers. One popular one is available at the following page:

http://winhelp2002.mvps.org/hosts.htm

Basically what is offered is a copy-and-paste way to block sites through your Hosts file, which can be simple and effective.

There is one caveat with using a solution such as the MVPS HOSTS file: It can have some unexpected results. One rather personal example is that the MVPS HOSTS file blocks anything related to a popular e-mail fulfillment service known as AWeber. It just so happens that WindowsTips (and other Tips.Net publications) utilizes AWeber for publishing newsletters. That means that on a system that includes, in its Hosts file, information copied and pasted from the MVPS HOSTS file, the user won't be able to click any of the links in the WindowsTips newsletter or any other Tips.Net newsletter. This occurs for reasons already discussed in this tip.

The moral of the story is that if you decide to use a Hosts-file-based solution provided by someone else, make sure that you understand what is actually being blocked. (You could use the MVPS HOSTS solution, but you'll want to search through the file for any entries containing the characters "aweber." Delete those lines—there should be two of them—and you can again access any links in Tips.Net newsletters, including the links in WindowsTips.)

As noted, using the Hosts file to block content is effective, but it is rather rudimentary because (1) you could always remove this line from your Hosts file, or (2) specify the IP address in your browser, thus bypassing your Hosts file altogether.

 This tip (12875) applies to Windows 7, 8, and 10.