Part two of that Slashdot article I mentioned before:
For some reason, this happens most frequently when I go to washingtonpost.com,
but it happens on other sites, too. I click on an article, and get
the message
Waiting for doubleclick.net
and then the web page hangs for awhile.
What's happening is that the Post is going to
doubleclick.net and waiting for advertisements to load up.
Of course, the net doesn't just go to doubleclick, it goes elsewhere
as well. And many of those ``elsewheres'' are nothing but annoying
ads.
Wouldn't it be great to get rid of those ads? OK, we can use
something like Adblock, and
I recommend that, but wouldn't it be wonderful to make your computer
believe that places like doubleclick never existed? (And,
incidentally, decrease worries about your privacy.) There is a way.
Let's go back to the early days of the Internet. There was
nothing like the current Domain Name Service (DNS). Oh, each web site had an IP address, but there were no
central directories to tell you which IP address belonged to Google (not that Google
existed back then).
So how would you have found Google? In order to find things on
the Internet, each computer had a file called /etc/hosts.
(OK, each Unix-like computer had such a file. I have no idea what
other OS called it.) In the /etc/hosts file was a line
like:
216.239.41.104 www.google.com
which told your computer the IP address of Google. Of course, this file had to be upgraded periodically by downloading a new file from somewhere, and eventually it got so big that the whole thing had to be scrapped and DNS was adopted. But, the /etc/hosts file still exists, and it's read before your computer goes out to your chosen name server!
This is really quite useful. If you use Google a lot, for
example, adding the line
216.239.41.104 www.google.com
to /etc/hosts saves you from having go to the DNS every
time you want to do a search. And there's another use:
Near the top of /etc/hosts is a line like
127.0.0.1 localhost.localdomain localhost
This tells your computer where your local computer lives on your
local network (even if you don't have a local network). If you try
to go to localhost from your web browser, you'll get a
message like
The connection was refused when attempting to contact localhost
(Unless you are running your own web server, in which case you'll
get your home page.) In this case, localhost and
localhost.localdomain function as aliases for the address
127.0.0.1. Any request to go to localhost takes
you to 127.0.0.1, and does whatever you tell it to.
Now suppose the webpages you visit regularly connect you to a
scuzzy site we'll call reallystupidads.com. You're tired
of these ads and never want to see them again. What to do?
Remember that /etc/hosts is read first, before the request
goes out to the DNS. So add a line
127.0.0.1 reallystupidads.com
to /etc/hosts. Now, when
that page you are interested in asks reallystupidads.com
send some advertisements, your computer looks up the address, finds
that it is 127.0.0.1, and does whatever you've set it up to
do. If you don't run your own web server, it does nothing.
It's as if that site never existed.
So, what you need is a list of really annoying sites that should
be banned from your computer. Of course, this being the Internet,
there are many such lists. The one I'm using is Mike Skallas' Ad Blocking Hosts file. Basically, you add it to
/etc/hosts. And, frabjous day, there are instructions for doing the same thing in Windows
2000 and XP.
And, of course, once you know the trick, you can add your own
annoying sites to the list. Parents can add sites that they want to
keep their children out of, e.g.
Hopefully no one will add
127.0.0.1 hawknotes.blogspot.com
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