Gizmo's Tech Support Alert

It seems that almost every web page you view these days has Google AdSense texts ads spread across the top or down the side.

These ads have never bothered me. They are easy enough to ignore and besides, webmasters are entitled to earn a living just like the rest of us.

However, lately some sites have started embedding the Google ads in the center of the page or worse still, right in the middle of a block of text. So I decided enough was enough and started looking for ways to block the ads.

It turns out that it's dead easy to stop them. In fact there are many ways you can do it. For example Firefox users can use the AdBlock or CustomizeGoogle extensions to kill the ads while Internet Explorer users can use one of the many ad-blocker add-ins such as AddSubtract or WebWasher.

Perhaps the simplest and most universally applicable method is to use the Windows Hosts file to block the address of the Google ad-server.

There is another advantage in using this technique; it will help you develop an understanding of the Hosts file and its many uses.

The Windows Hosts file

This a file on your computer that can be used to locally translate the names of web sites into IPs. IPs are sets of four numbers separated by dots like 65.109.128.16. They are the real addresses of the internet not web site names (URLS). Names are only a convenience and have to be translated into IPs. For example, the name (URL) of my website is techsupportalert.com but its IP, its "real" address on the internet, is actually 65.109.128.16.

Normally this kind of translation takes place at your ISP. They have a special server dedicated to the task called a DNS server. Whenever you type a URL like www.techsupportalert.com into your browser address window, the DNS server translates the name into the corresponding IP; 65.109.128.16. It's automatic and requires no involvement from you.

However, you can also do it locally on your own PC and that's where the Windows Hosts file comes into play.

The Hosts file is just a plain text file containing a simple list of web site names (URLs) and their corresponding IPs. Here's an example of what a Hosts file might look like:

216.109.118.69  www.yahoo.com
65.109.128.16   www.techsupportalert.com
216.239.115.141 www.cnet.com

You can think of this like an address book. In an address book you look up a name and find the address. With the Hosts file you look up a web site name (URL) and find the address (IP). In the example above, any reference to the name www.yahoo.com will directed to the address 216.109.118.69.

Now, the Hosts file on most computers has nothing in it. That's fine because the DNS translation is usually handled by your ISP.

If your Hosts file does have entries then these are used for the DNS translation for those sites instead of your ISPs DNS server. This is actually fractionally quicker as it saves a step. In fact. some web accelerators store thousands of popular sites in your Hosts file to take advantage of this slight increase in speed.

But there's another common usage for the Hosts file: to block addresses. This is done by using a dummy address, typically 127.0.0.1, that goes nowhere. For example, consider this entry:

127.0.0.1 wwww.yahoo.com

With this entry in the hosts file, any reference to www.yahoo.com will be redirected to the address 127.0.0.1. Now that address is not a valid web address for any real web site. In fact, by convention it refers to your own computer.

If you have this entry in your Hosts file and you type www.yahoo.com into your browser, you'll get an error message: "Host cannot be found."

This is the very technique that we can use to block Google text ads.

Stopping Google Ads with the Hosts File

All the Google text ads seem to come from the address pagead2.googlesyndication.com. If we place that name in the Windows Hosts file and point it to a dummy address then the Google ads will not appear.

First though, we need to locate the hosts file. Here is the usual location for the major Windows versions:

Windows 9x, ME C:\WINDOWS
Windows NT (and some 2K) C:\WINNT\system32\drivers\etc Windows 2K, XP, 2003 C:\WINDOWS\system32\drivers\etc

The Hosts file is simply called "HOSTS" and has no file extension.

It's a simple text file and must only be changed with a plain text editor like Notepad and never a word processing program such as MS Word.

First, we need to open the Hosts file in Notepad. If you don't know how to do that then locate the Hosts file in Windows Explorer and right-click on it. Select "Open" and then check "Select the program from a list." You'll then be presented with list of programs; select Notepad. You should now see a simple text file.

Go to the first blank line at the bottom of the file and type in this entry:

127.0.0.1 pagead2.googlesyndication.com

Make sure you leave no blank lines before this entry.

Just save the file and you are finished. Saving this change may spark an alert from your anti-spyware software but it's OK, just approve the change.

If you've followed the instructions carefully you should never see Google AdSense text ads again. If at a future stage you want to see the ads again, just use Notepad to delete the line you just added.

The same technique can be used to block other advertising servers, malicious spyware or sites containing inappropriate material. In fact a number of folks offer free downloads of Hosts files containing thousand of entries of such unwanted sites.

I'm not a great fan of using the Hosts file for such large scale blocking. To me it's too unselective - I prefer to know exactly what I am blocking and this is virtually impossible with a list containing thousands of sites. However if you want to play with this kind of application, here are some Host file download sites:

http://www.hosts-file.net/
http://www.mvps.org/winhelp2002/hosts.htm

Dedicated Host file enthusiasts may want to check out Hostess, a free Hosts file editor/manager you can get from here:
http://accs-net.com/hostess/.

Gizmo