Symantec Norton Personal Firewall 2003, User Manual

Page: 96 / 151

Blocking Internet advertisements
Enable or disable Ad Blocking
96
Blocking by location
Every file on the Internet has a unique address or URL . When you view a
Web page, your computer connects to a URL and displays the file that is
stored there. If the page points to graphics, audio files, and other
multimedia content, your
browser displays the files as part of the page.
When you go to a Web page that includes a banner ad , the instructions used
to display the page might include the following:
<p>Greetings from the Ajax company<img src="http://www.ajax.com/
nifty_images/image7.gif">
Your browser displays the text Greetings from the Ajax company on the
screen. Then it connects to www.ajax.com and requests a file called
/nifty_images/image7.gif. (The suffix .gif indicates that this is a Graphics
Interchange Format file, a common image file format.) The computer at
www.ajax.com sends the file to the browser, which displays the image.
When Ad Blocking is enabled and you connect to a Web site, Norton
Personal Firewall scans Web pages and compares their contents to two
lists:
See “Keeping
current with
LiveUpdate”
on
page 53.
1
A default list of ads that Norton Personal Firewall blocks
automatically. Use LiveUpdate to keep the list of blocked ads current.
1
A list that you create as you block specific ads. You can add to and
change this list.
If the page includes files from a blocked domain , Norton Personal Firewall
removes the link and downloads the rest of the page.
Enable or disable Ad Blocking
Norton Personal Firewall searches for the addresses of the ads that are
being blocked as the Web page is downloaded by your
browser . If it finds an
address that matches the list of ads to block, it removes the ad so that it
does not appear in your browser. It leaves the rest of the Web page intact so
that you can view the page without the advertisements.
To enable or disable Ad Blocking
1
Open Norton Personal Firewall.