Use the HOSTS File to Block Web Sites

By: Stephen Bucaro

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Use the HOSTS File to Block Web Sites

By Stephen Bucaro

When you type a domain name into your Web browser, Internet
Protocol contacts a computer that is a domain name server
to look up the IP address of the Web site. In the early
days, the Internet didn't need domain name servers. Every
computer had a file named HOSTS that listed the domain name
and IP address of the systems connected to the Internet.

Even today when your Web browser needs to resolve a domain
name to an IP address, it first looks for a file named
HOSTS on the local computer. In Windows NT, the HOSTS file
is located in c:windowssystem32drivers. In Windows 9x,
the HOSTS file is located in c:windows.

Because the HOSTS file is no longer required, you may not
find it on your computer.

Instead, you might find a file
named HOSTS.SAM, the SAM extension meaning "SAMPLE". You
might also find a file named LMHOSTS. The LMHOSTS file was
used to resolve NetBIOS names to IP addresses.

The HOSTS file is simply a text file with a list of IP
addresses and their respective domain names. You can open
the file with Windows Notepad. The HOSTS file may list only
one IP address, the loopback address, as shown below. localhost

To block a Web site, enter an IP address that is not
allowed for the Web. For example, any IP address with the
first digit of 0 would be on the local network. Any IP
address with the first digit of 127 is looped back. Then
map that IP address to the domain name that you want to

For example, suppose you want to block a porn site that
your teenager has been visiting, you might add an entry
like the one shown below.

Banner ads are usually hosted on an advertiser's domain and
linked to sites all over the Web. Suppose you want to block
annoying banner ads displayed at a site that you visit
frequently. You might add an entry like the one shown below.

Then when a file from that domain name is requested,
instead of the porn site or the banner being displayed, the
browser will display the message "The Page Cannot be

When you save the HOSTS file after editing, make sure that
the file name does not have an extension. Sometimes Windows
Notepad adds the extention .txt.

The HOSTS file is a quick, easy way to block access to a
Web site. But if you use this method to block a porn site
that your teenager has been visitingFree Reprint Articles, make sure they don't
find this article.
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