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<title>
Internet Junkbuster Frequently Asked Questions
</title>
<base href="http://www.junkbusters.com/ht/en/ijbfaq.html">
<meta name="description" content="An extensive FAQ on the Internet Junkbuster, free software to removes banner ads, cookies, and other stuff you don't want from your web browser.">
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<body bgcolor="#f8f8f0" link="#000078" alink="#ff0022" vlink="#787878">
<center>
<h1><a name="top_of_page">Internet J<small>UNK<i><font color=red>BUSTER</font></i></small> Frequently Asked Questions
</a></h1>
</center>
<font face="arial, helvetica">
<p align="center">
<a href="#browser">Configuring Browsers</a>
<font color="#ff0000">
<b> &#183; </b></font><a href="#local">Installation</a>
<font color="#ff0000">
<b> &#183; </b></font><a href="#companies">For Companies</a>
<font color="#ff0000">
<b> &#183; </b></font><a href="#blocking">Blocking</a>
<font color="#ff0000">
<b> &#183; </b></font><a href="#cookies">Cookies</a>
<font color="#ff0000">
<b> &#183; </b></font><a href="#anonymity">Anonymity</a>
<font color="#ff0000">
<b> &#183; </b></font><a href="#security">Security</a>
</p>
</font><br>
<center>
<h2><a name="top"><font face="arial, helvetica">
The Top Ten Questions
</font></a>
</h2>
</center>
<br>For a list of the questions on this page (without the answers),
see our
<a href="toc.html#ijbfaq">Table of Contents.</a>
It also contains detailed pointers into our pages on busting 
<a href="junkemail.html">junk e-mail,</a>
<a href="junkmail.html">junk mail</a>
and
<a href="telemarketing.html">telemarketing calls.</a>

<h3><a name="what" href="/cgi-bin/gp?pg=ijbfaq&pr=what"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
What is the Internet Junkbuster and what does it do for me?
</h3>
<p>
The
Internet Junkbuster
Proxy
<a href="legal.html#marks"><small><sup>TM</sup></small></a>
blocks requests for
<small>URL</small>s
(typically banner ads)
that match its
<a href="ijbfaq.html#blocking">blockfile.</a>
It also deletes
<a href="ijbfaq.html#cookies">cookies</a>
and other
unwanted identifying
<a href="ijbfaq.html#anonymity">header information</a>
that is exchanged between web servers and browsers.
These headers are not normally accessible to users
(even though they may contain information that's important to your privacy),
but with the
Internet Junkbuster
you can see almost
<a href="ijbman.html#o_d">anything you want</a>
and control everything you're likely to need.
<b>You</b>
<a href="over.html#you_def">decide what's junk.</a>
<a href="legal.html#marks"><small><sup>SM</sup></small></a>
</p>

<h3><a name="free" href="/cgi-bin/gp?pg=ijbfaq&pr=free"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Is there a license fee / warranty / registration form / expiration?
</h3>
<p>
No, none of these.
It's completely free of charge.
Junkbusters
offers you the software to copy, use, modify and distribute
as you wish, forever, at
<a href="over.html#nobucks">no charge</a>
under the
<a href="gpl.html">GNU General Public License.</a>
<p>
<a name="warranty">It comes with</a>
<a href="gpl.html#nowarr">no warranty of any kind.</a>
<p>
<a name="register">You don't have to register,</a>
in fact we don't even provide a way to do so:
the practice of registering software is
almost always just an
<a href="links.html#smog">excuse</a>
to send you solicitations and
<a href="self.html#warranty">sell your name</a>
and information about your behavior.
You are welcome to obtain and use our software as anonymously you wish.
(Your
<small>IP</small>
address will naturally be
<a href="http://www.junkbusters.com/cgi-bin/privacy">disclosed</a>
when you download it,
so if you work for a web ad company
you might want to use a service such as the
<a href="ijbfaq.html#anonymizing">lpwa.com</a>
when you get it.
We
<a href="over.html#nopriv">never</a>
want to be given any information that you consider private or confidential.)
<p>
<a name="why">We are often asked why we give away a product that many</a>
would happily pay for.
The answer is that we are determined to carry out our
<a href="over.html">mission:</a>
to free the world from junk communications.
</p>

<h3><a name="windows" href="/cgi-bin/gp?pg=ijbfaq&pr=windows"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Does it run on Windows? On a Mac? On the AOL browser?
</h3>
<p>
For the latest information on availability, see the
<a href="ijbdist.html">Distribution Information</a>
page.
But you don't need to have it running on your computer
if you get your
<small>ISP</small>
or Systems Administrator at
<a href="ijbfaq.html#companies">work</a>
to run it.
</p>

<h3><a name="isp" href="/cgi-bin/gp?pg=ijbfaq&pr=isp"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
How can I get my ISP to run the Internet Junkbuster?
</h3>
<p>
First check whether they already are.
Most
<small>ISP</small>s
would announce this on their ``News'' page
or their pages for new subscribers.
If they state that they are considering whether to install it,
allow them
<a href="ijbfaq.html#isps">time to do it.</a>
<a name="switch">If they say they will not provide it,</a>
you might want to consider switching to 
an
<small>ISP</small>
that
<a href="ijbfaq.html#does">does.</a>
<p>
<a name="unaware">If they appear to be unaware of it,</a>
you might send them email including the follow
<small>URL</small>,
asking them
to provide the
Internet Junkbuster
for their customers.
<br>
<big><kbd>http://www.junkbusters.com/ht/en/ijbfaq.html#isps</kbd></big>
</p>

<h3><a name="who" href="/cgi-bin/gp?pg=ijbfaq&pr=who"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Who chooses the options that control what is blocked?
</h3>
<p>
Whoever starts the
Internet Junkbuster
chooses the options and the blockfile.
If your 
<small>ISP</small>
runs it for you, they have to make these decision
(though
<a href="http://www.lunatech.com/proxy/">some</a>
may give you a choice of proxies,
and a way to suggest new
<small>URL</small>s
to block).
If you run it on your computer,
<b>You</b>
<a href="over.html#you_def">decide what's junk.</a>
<a href="legal.html#marks"><small><sup>SM</sup></small></a>
</p>

<h3><a name="self" href="/cgi-bin/gp?pg=ijbfaq&pr=self"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
How do I run the code on my computer?
</h3>
<p>
If you have a C compiler and are using
<small>UNIX <a href="legal.html#not_our_trademark">&#174;</a></small>
or Windows 95 or NT,
you
<a href="ijbfaq.html#local">download it, compile it, start it running,</a>
and then
<a href="ijbfaq.html#browser">configure your browser.</a>
<p>
<a name="port">If you are using any other operating system</a>
you would need to port the code.
You are welcome to do this, and if you would like
us to consider publishing your ported version,
please
<a href="/cgi-bin/gp?pg=ijbfaq&pr=port">tell us.</a>
</p>

<h3><a name="show" href="/cgi-bin/gp?pg=ijbfaq&pr=show"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
How can I tell which blockfile and options are being used?
</h3>
<p>
Your
<small>ISP</small>
should have a page specifying the options they chose,
but you can check by going to
<a href="http://internet.junkbuster.com/cgi-bin/show-proxy-args">http://internet.junkbuster.com/cgi-bin/show-proxy-args</a>
or to any
<small>URL</small>
ending in
<big><kbd>show-proxy-args</kbd></big>
(even if it doesn't exist).
It needn't exist because the
Internet Junkbuster 2.0
intercepts the request, blocks it,
and returns in its place
information about itself.
This is also useful for checking that your browser really is
going through an
Internet Junkbuster.
Some people set the home page of their browser to such a
<small>URL</small>
to be sure that it is configured to use the proxy.
<p>
<a name="headers">If you wish to check the header information</a>
your proxy is actually sending,
a visit to
<a href="http://internet.junkbuster.com/cgi-bin/show-http-headers">http://internet.junkbuster.com/cgi-bin/show-http-headers</a>
will give you the more relevant ones first.
You might also like to turn the proxy
<a href="ijbfaq.html#discontinue">off</a>
and compare the difference. (Don't forget to turn it back on again.)
</p>

<h3><a name="responding" href="/cgi-bin/gp?pg=ijbfaq&pr=responding"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
My browser started giving me ``server not responding'' messages
</h3>
<p>
Once your browser is told to use a proxy such as the
Internet Junkbuster,
it thinks of it as its server for everything,
so this message means it can't talk to the proxy.
The
Internet Junkbuster
may not be running,
or you may have specified its proxy
<a href="ijbfaq.html#address">address</a>
incorrectly.
Check that the details you entered are correct.
If you have
<big><kbd>telnet</kbd></big>
you can try connecting to the appropriate port to see if the
Internet Junkbuster
is running.
If your
<small>ISP</small>
is running the
Internet Junkbuster,
you may want to check with them.
If you are running it yourself under
<small>UNIX <a href="legal.html#not_our_trademark">&#174;</a></small>,
try looking at a
<big><kbd>ps ax</kbd></big>
to see if it is running.
The
<a href="ijbman.html#o_h">port</a>
specified in its options should be the same one as your
browser has configured.
</p>

<h3><a name="idea" href="/cgi-bin/gp?pg=ijbfaq&pr=idea"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
I've got this great idea for a new feature. Who do I tell?
</h3>
<p>
We'd be very interested to hear it, but please bear a few things in mind.
<br><ul  type="1">
<li>
<a name="considered">Please check this FAQ to see if we've already considered</a>
the idea,
such as
<a href="ijbfaq.html#size">automatic detection</a>
of banner ads
and
<a href="ijbfaq.html#broken">replacing ads</a>
with something else such as a
transparent
<small>GIF</small>.
<li>
<a name="confidential">Don't tell us anything you want to keep confidential</a>
or retain some right over.
<li>
<a name="wish">We currently have a</a>
long wish list of things that we may or may not do
in the near future, including
a version for your favorite computer and a plug-in version.
<li>
<a name="go4it">If you don't want to wait</a>
you're welcome to improve on our code, publish your version on the Web,
and
<a href="/cgi-bin/gp?pg=ijbfaq&pr=idea">tell us</a>
where to find it.
Ports to platforms such as the Mac are most welcome.
</ul>
</p>

<h3><a name="other" href="/cgi-bin/gp?pg=ijbfaq&pr=other"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
My question isn't listed here. Who do I ask for support?
</h3>
<p>
The answer to detailed technical questions may be answered in
<a href="ijbman.html">manual page</a>,
or in the source code.
Also double-check this page for an answer:
using the ``find'' feature on your browser for likely keywords may help.
<p>
<a name="them">If your</a>
<small>ISP</small>
is providing
the
Internet Junkbuster
for you,
and your question is about how to use it,
check their web page before asking them.
<p>
<a name="us">Even though we don't offer the kind of</a>
support you might expect if you paid a lot of money for a software product,
you can still ask us.
But before you do, please consider whether
you could ask someone closer to you.
And please be patient if we're slow to reply: we
<a href="over.html#nobucks">never charge consumers </a>
for our services,
so we have to subsidize consumers with revenue from companies,
and our resources are limited.
<p>
<a name="quote">If your company or organization</a>
would be interested in a maintenance contract
with phone and email support,
hard copy documentation and source code and pre-compiled binaries on tape
or disk,
please
<a href="/cgi-bin/gp?pg=ijbfaq&pr=quote">ask us</a>
for a quote.
</p>
<p align="center"><a href="#top_of_page"><img border=0 width=250 height=15 src="/images/top.gif" alt="--- Back to Top of Page ---"></a></p>
<br>
<center>
<h2><a name="browser"><font face="arial, helvetica">
Configuring your browser to talk to the Internet Junkbuster
</font></a>
</h2>
</center>
<br>
<h3><a name="address" href="/cgi-bin/gp?pg=ijbfaq&pr=address"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
What is the proxy address of the Internet Junkbuster?
</h3>
<p>
If your
<small>ISP</small>
or company is running 
the
Internet Junkbuster
for you,
they will tell you the address to use.
It will be the name of the computer it's running on
(or possibly its numeric IP address),
plus a port number.
Port 5865 is the default, so assume this number if it is not unspecified.
Sometimes a colon is used to glue them together,
as in
<big><kbd>junkbuster.pro-privacy-isp.net:5865</kbd></big>
but
with most browsers
you do not type the colon,
you enter the address and port number separately.
<p>
<a name="localhost">If you are running</a>
the
Internet Junkbuster
on your computer,
the machine will probably be
<big><kbd>localhost</kbd></big>
and
the port will be 5865 unless you have told the
Internet Junkbuster
to
run on a different port with the
<a href="ijbman.html#listen-address">listen-address</a>
option.
</p>

<h3><a name="set" href="/cgi-bin/gp?pg=ijbfaq&pr=set"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
How do I tell the browser where to find the Internet Junkbuster?
</h3>
<p>
All current browsers can be told which proxy to use.
You enter the same information under two lines: one for
<small>HTTP</small>,
and one for the Secure Protocol if your browser supports
<small>SSL</small>.
If you find some information already entered for your proxy,
see the next question.
Here are the menus you go through to get to the proxy configuration settings.
(We also recommend that you
<a href="links.html#java">disable Java</a>,
which is a separate operation.)
<br><ul  type="1">
<li>
<a name="netscape">For</a>
<a href="http://www.netscape.com/comprod/products/navigator/version_3.0/index.html">Netscape</a>
2.01, 2.02 and 3.0:
<b><font face="arial, helvetica">
Options</font></b>;
<b><font face="arial, helvetica">
Network Preferences</font></b>;
<b><font face="arial, helvetica">
Proxies</font></b>;
<b><font face="arial, helvetica">
Manual Proxy Configuration View </font></b>
(enter details under
<b><font face="arial, helvetica">
HTTP</font></b>
and
<b><font face="arial, helvetica">
Security Proxy</font></b>)
<b><font face="arial, helvetica">
OK</font></b>;
<b><font face="arial, helvetica">
OK</font></b>.
<br>
With Netscape 2.0,
follow with
<b><font face="arial, helvetica">
Options</font></b>,
<b><font face="arial, helvetica">
Save Options</font></b>.
<br>
<a name="Netscape4.02">With Netscape 4.02, you first have to go through</a>
<b><font face="arial, helvetica">
Edit/Preferences</font></b>.
Then in the frame on the left,
click on triangle pointing to the right towards the word
<b><font face="arial, helvetica">
Advanced</font></b>;
it will switch to a triangle pointing down;
and the words
<b><font face="arial, helvetica">
Cache</font></b>,
<b><font face="arial, helvetica">
Proxies</font></b>
and
<b><font face="arial, helvetica">
Disk Space</font></b>
appear.
Click on
<b><font face="arial, helvetica">
Proxies</font></b>
and the frame on the right will
display a banner saying
<b><font face="arial, helvetica">
Proxies Configure proxies to access the Internet</font></b>.
Click the radio button labeled
<b><font face="arial, helvetica">
Manual proxy configuration</font></b>
then click the button labeled
<b><font face="arial, helvetica">
View</font></b>
and the continue the procedure above for Version 3.
<li>
<a name="explorer3">For</a>
<a href="http://www.microsoft.com/ie/support/docs/tech30/">Internet Explorer 3.0:</a>
<b><font face="arial, helvetica">
View</font></b>;
<b><font face="arial, helvetica">
Options</font></b>;
<b><font face="arial, helvetica">
Connections</font></b>;
tick
<b><font face="arial, helvetica">
Connect through proxy server</font></b>
box;
<b><font face="arial, helvetica">
Settings</font></b>;
enter details into the 
<b><font face="arial, helvetica">
HTTP</font></b>
Box, with port number in the second box;
same with Secure;
<b><font face="arial, helvetica">
OK</font></b>.
<li>
<a name="explorer2">For Internet Explorer 2.0: </a>
<b><font face="arial, helvetica">
View</font></b>;
<b><font face="arial, helvetica">
Options</font></b>;
<b><font face="arial, helvetica">
Proxy</font></b>;
enter details;
<b><font face="arial, helvetica">
OK</font></b>.
<li>
<a name="nt">On NT for MS-IE:</a>
<b><font face="arial, helvetica">
Control Panel</font></b>;
<b><font face="arial, helvetica">
Internet</font></b>;
<b><font face="arial, helvetica">
Advanced</font></b>;
<b><font face="arial, helvetica">
Proxy</font></b>.
<li>
<a name="if">For MS-IE 4.0: we're told it's the same as for 3.0.</a>
Please
<a href="/cgi-bin/gp?pg=ijbfaq&pr=set">tell us</a>
if you see any differences.
<li>
<a name="mosaic">For NCSA Mosaic for Windows:</a>
<b><font face="arial, helvetica">
Options</font></b>,
<b><font face="arial, helvetica">
Preferences</font></b>,
<b><font face="arial, helvetica">
Proxy</font></b>;
enter details under
<b><font face="arial, helvetica">
HTTP</font></b>.
<li>
<a name="Opera">For</a>
Opera:
<b><font face="arial, helvetica">
Preferences</font></b>,
<b><font face="arial, helvetica">
Proxy servers</font></b>;
check the box next to HTTP;
enter the server and port number in the box on the other side;
click
<b><font face="arial, helvetica">
OK</font></b>.
<li>
<a name="lynx">For</a>
<a href="http://www.yahoo.com/Computers_and_Internet/Software/Internet/World_Wide_Web/Browsers/Lynx">Lynx,</a>
<a href="http://www.yahoo.com/Computers_and_Internet/Software/Internet/World_Wide_Web/Browsers/Mosaic/">Mosaic/X,</a>
<a name ="grail" href="http://monty.cnri.reston.va.us/grail-0.3/">Grail,</a>
and
W3O
<a href="http://www.w3.org/pub/WWW/Arena/">Arena,</a>
you can specify the proxy via environment variables
before starting the application.
This will probably be done with something like either
<br>
&#160;&#160;&#160;<big><kbd>setenv http_proxy http://localhost:5865/</kbd></big>
<br>
or
<br>
&#160;&#160;&#160;<big><kbd>http_proxy=http://junkbuster.pro-privacy-isp.net:5865/ export http_proxy</kbd></big>
<br>
depending on your shell and where the
Internet Junkbuster
lives.
</ul>
If your browser is not listed here,
or if you notice an error, please
<a href="/cgi-bin/gp?pg=ijbfaq&pr=set">tell us</a>
the correct procedure.
</p>

<h3><a name="already" href="/cgi-bin/gp?pg=ijbfaq&pr=already"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
What should I do if I find another proxy is already configured?
</h3>
<p>
This is the case if you already find values
set where you would enter the proxy details,
or if anything is entered under
<a name="Automatic">Automatic Proxy Configuration</a>
(in the case of 
<a href="http://home.netscape.com/eng/mozilla/2.0/relnotes/demo/proxy-live.html">Netscape</a>
and
<a href="http://ieak.microsoft.com/">MS-IE 3.0</a>
and above).
It's probably a firewall proxy between your company and the outside world,
<a name="cache">or a</a>
<a href="http://vancouver-webpages.com/CacheNow/">caching proxy</a>
if you're using an 
<small>ISP</small>.
<p>
<a name="f">What needs to be done in this case is to</a>
use the
<a href="ijbman.html#forwardfile">forwardfile</a>
option
to tell the
Internet Junkbuster
the address of the other proxy.
Specify a different (unused) port number
with the
<a href="ijbman.html#listen-address">listen-address</a>
option,
and configure your browser to
<a href="ijbfaq.html#chain">use that port.</a>
If you haven't done this kind of thing before,
it's probably best to consult your systems administrator or 
<small>ISP</small>
about it;
check their web page first.
</p>

<h3><a name="discontinue" href="/cgi-bin/gp?pg=ijbfaq&pr=discontinue"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
What if I want to stop using the Internet Junkbuster?
</h3>
<p>
Just go through the same procedure you used to start your
browser using the
Internet Junkbuster,
but remove the details you put in
(or if there was something there before, restore it).
You may need to use
<b><font face="arial, helvetica">
Save Options</font></b>
to make this change permanent.
On Netscape 3.0 you can go through
<b><font face="arial, helvetica">
Options</font></b>;
<b><font face="arial, helvetica">
Network Preferences</font></b>;
<b><font face="arial, helvetica">
Proxies</font></b>
and click on
<b><font face="arial, helvetica">
No Proxy</font></b>
to turn it off, and later click on
<b><font face="arial, helvetica">
Manual Proxy Configuration</font></b>
if you want to start using it again.
(No need to enter the again details under
<b><font face="arial, helvetica">
View</font></b>
as you did the
<a href="ijbfaq.html#netscape">first time;</a>
they should remain there unchanged.)
</p>

<h3><a name="dial" href="/cgi-bin/gp?pg=ijbfaq&pr=dial"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Automatic dialing isn't working any more. How do I fix it?
</h3>
<p>
Some browsers (such as MSIE-4) can be configured to dial your
<small>ISP</small>
automatically when you click on a link,
but this feature gets disabled if you specify a proxy running on your
own computer
(with address
<big><kbd>localhost</kbd></big>
or
<big><kbd>127.0.0.1</kbd></big>)
because these addresses don't require dialing.
The
Internet Junkbuster
knows nothing about dialing, so it doesn't work.
To make automatic dialing work,
make up a name such as
<big><kbd>junkbuster.ijb</kbd></big>
and use it in the proxy settings
instead of
<big><kbd>localhosts,</kbd></big>
and then add the line
<big><kbd>127.0.0.1 junkbuster.ijb</kbd></big>
to the file
<big><kbd>c:\windows\hosts</kbd></big>
(if there already is a line beginning with
<big><kbd>127.0.0.1</kbd></big>
just add
<big><kbd>junkbuster.ijb</kbd></big>
at the end of it.)
<p>
<a name="also">This should also work Netscape Communicator 4 on</a>
machines where IE-4 has been installed.
</p>
<p align="center"><a href="#top_of_page"><img border=0 width=250 height=15 src="/images/top.gif" alt="--- Back to Top of Page ---"></a></p>
<br>
<center>
<h2><a name="local"><font face="arial, helvetica">
Setting up the Internet Junkbuster on your local computer
</font></a>
</h2>
</center>
<br>You currently need a C compiler to do this.
<a name="install">For information on the availability of an executable version</a>
under Windows,
see the
<a href="ijbdist.html">distribution page.</a>

<h3><a name="u" href="/cgi-bin/gp?pg=ijbfaq&pr=u"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
How do I compile the code under Unix?
</h3>
<p>
If you are running Redhat
<a href="aboutus.html#linux">Linux</a>
you may prefer to use the
<a href="ijbdist.html#red">rpm</a>
instead of the following procedure.
<br><ol  type="1">
<li>
<a name="download">Download</a>
<a name="tar">the</a>
<a href="ijb20.tar.Z">tar file</a>
(~277k)
and uncompress and extract the files from it with this command
<br>
&#160;&#160;&#160;<big><kbd>uncompress -c ijb20.tar.Z | tar xf -</kbd></big>
<p>
<li>
<a name="sun">If your operating system is from</a>
<a href="legal.html#not_our_trademark">Sun</a>
or
<a href="legal.html#not_our_trademark">HP</a>
examine the
<big><kbd>Makefile</kbd></big>
and make any changes indicated inside.
<li>
<a name="make">Run</a>
<br>
<br>
&#160;&#160;&#160;<big><kbd>make</kbd></big>
<p>
<li>
<a name="defaults">Copy the sample configuration file</a>
(<big><kbd>junkbstr.ini</kbd></big>,
previously called
<big><kbd>sconfig.txt</kbd></big>
and other names in earlier releases)
to some convenient place such as
<big><kbd>/usr/local/lib/junkbuster/configfile</kbd></big>
or whatever you choose.
The sample file has all the options commented out.
You can remove the
<big><kbd>#</kbd></big>
character on any that you want, but it may be better to
leave this until to later.
Run it asynchronously:
<br>
<br>
&#160;&#160;&#160;<big><kbd>junkbuster configfile &</kbd></big>
<p>
If you are running a version earlier than 2.0 you can start it with
<big><kbd>junkbuster &</kbd></big>
<p>
<li>
<a name="config">Configure your browser (described</a>
<a href="ijbfaq.html#browser">above).</a>
<li>
<a name="test">Verify that the</a>
Internet Junkbuster
is working (described
<a href="ijbfaq.html#show">above).</a>
<li>
<a name="restart">Decide on the options you really want,</a>
<big><kbd>kill</kbd></big>
the
<a href="ijbfaq.html#pid">process</a>
and start it again. The most popular option is
<a href="ijbman.html#blockfile">blockfile</a>
to block ads.
<a name="comprehensive">A sample blockfile is provided as an illustration,</a>
but it doesn't really stop many ads.
More comprehensive ones are available
<a href="ijbfaq.html#readymade">elsewhere</a>.
<li>
<a name="rc">You'll probably want to add an entry to</a>
<big><kbd>/etc/rc.d/rc.local</kbd></big>
or equivalent to start it at boot time.
(Any output you specify should be redirected to a file.
And don't forget the
&amp;
at the end to run it asynchronously or your system will seize
up after the next reboot.)
</ol>
</p>

<h3><a name="win" href="/cgi-bin/gp?pg=ijbfaq&pr=win"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
How do I compile the code under Windows?
</h3>
<p>
A binary is currently being supplied with the source code,
but if you prefer to compile it yourself here is the likely procedure.
Most of these steps are repeated in our checklist for
<a href="ijbwin.html">installation under Windows.</a>
<br><ol  type="1">
<li>
<a name="zip">Download</a>
<a href="ijb20.zip">zip file</a>
called
<big><kbd>ijb20.zip</kbd></big>
(~202k),
then uncompress and unpack the zip archive using a tool like
<a href="http://www.winzip.com/">WinZip</a>.
<li>
<a name="change">Now the distribution (source and sample files)</a>
will be in a directory
called
<big><kbd>ijb20</kbd></big>.
Change to that directory and then edit the Makefile for
your system,
removing the comment character
(<big><kbd>#</kbd></big>)
in the lines related to Win32.
Then type:
<br>
&#160;&#160;&#160;<big><kbd>nmake</kbd></big>
<br>
This should create an executable called
<big><kbd>junkbstr.exe</kbd></big>.
<a name="compilers">For information on issues with various compilers, see the</a>
<a href="ijbdist.html#compilers">Distribution Information</a>
page.
<li>
<a name="attempt">Run the executable with the command:</a>
<br>
&#160;&#160;&#160;<big><kbd>junkbstr</kbd></big>
<br>
The program will produce a message
indicating that it has started and is ready to serve.
<p>
<a name="ini">(Version 2.0.1 and above uses</a>
the file
<big><kbd>junkbstr.ini</kbd></big>
as the config file
if it exists and no argument was given. If you have an earlier
version or if you want it to use a different config file,
simply specify that file as the argument.)
<li>
<a name="configures">Configure your browser (described</a>
<a href="ijbfaq.html#browser">above).</a>
<li>
<a name="work">Check the proxy is working (described</a>
<a href="ijbfaq.html#check">below</a>).
<li>
<a name="shortcut">To have the proxy start itself automatically</a>
when you login to Win95,
drop the ``shortcut'' to the
<big><kbd>junkbstr</kbd></big>
executable into the StartUp folder:
<br>
&#160;&#160;&#160;<big><kbd>C:\Windows\Start Menu\Programs\StartUp</kbd></big>
<br>
You might want to change the shortcut's
<big><kbd>Properties-&gt;Shortcut</kbd></big>
to
<big><kbd>Run: Minimized</kbd></big>.
If you specify the
<a href="ijbman.html#hide-console">hide-console</a>
option then the window will vanish after it starts.
<p>
<a name="NT">(WinNT users can put it into their own</a>
StartUp folders or the Administrator
can put it into the system's global StartUp folder.
It's probably worth making it a "service" under NT;
if you try this please
<a href="/cgi-bin/gp?pg=ijbfaq&pr=NT">tell us how.)</a>
</ol>
</p>

<h3><a name="check" href="/cgi-bin/gp?pg=ijbfaq&pr=check"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
How do I check that the proxy is working?
</h3>
<p>
Pick a page from somewhere (such as your bookmarks, or just one
that your browser was pointing to)
and
<b><font face="arial, helvetica">
Reload</font></b>
it.
If you get a message along the lines of ``server not responding,
using cached copy instead,'' see the advice
<a href="ijbfaq.html#responding">above.</a>
If the page reloads OK, check that your browser is actually
talking to the proxy by going to
<a href="http://internet.junkbuster.com/cgi-bin/show-proxy-args">http://internet.junkbuster.com/cgi-bin/show-proxy-args</a>
or any
<small>URL</small>
ending in
<big><kbd>show-proxy-args</kbd></big>
(as described
<a href="ijbfaq.html#show">below</a>,
the proxy should intercept the request.)
When you see ``Internet Junkbuster Proxy Status,''
you'll know it's working.
</p>

<h3><a name="chain" href="/cgi-bin/gp?pg=ijbfaq&pr=chain"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
How and why would I have this proxy chained with other proxies?
</h3>
<p>
You may need the 
<a href="ijbman.html#forwardfile">forwarding</a>
feature to ``daisy chain'' the
Internet Junkbuster
to another proxy, perhaps an
<a href="ijbfaq.html#anonymizing">anonymizing</a>
proxy to
<a href="ijbfaq.html#conceal">conceal</a>
your
<small>IP</small>
address,
or a
<a href="ijbfaq.html#cache">caching proxy</a>
from your
<small>ISP</small>,
or a
<a href="ijbfaq.html#firewall">firewall</a>
proxy between your company and the outside world.
Version 2.0
can be even configured to forward
<a href="ijbman.html#forwardfile">selectively</a>
according to the
<small>URL</small>
requested:
for example, connecting directly to trusted hosts,
but going through an anonymizing or firewall proxy for all other hosts.
<p>
<a name="administrator">Network administrators might use it to provide</a>
transparent access to multiple networks without
modifying browser configurations.
<a name="direct">Most browsers also provide a way of</a>
specifying hosts that the browser
connects to directly, bypassing the proxy. Some provide a method for
<a href="ijbfaq.html#Automatic">Automatic Proxy Configuration.</a>
A well written
Internet Junkbuster
configuration can be much more flexible and powerful.
<p>
<a name="example">An</a>
<small>ISP</small>'s
caching proxy
would typically be called something like
<big><kbd>cache.your-isp.net:5865</kbd></big>
(as described on you
<small>ISP</small>'s
web page);
you would put this information in your
<a href="ijbman.html#forwardfile">forwardfile</a>
as described in our manual.
Your browser would be configured to
the
Internet Junkbuster
for
<small>HTTP</small>
and Security Proxies as before,
but you probably want to tell it to use the caching proxy
for
<small>FTP</small>
and other protocols.
<a name="nonlocal">If your</a>
<small>ISP</small>
is running
the
Internet Junkbuster
for you,
they have probably already decided whether to chain with a caching proxy.
</p>

<h3><a name="socks" href="/cgi-bin/gp?pg=ijbfaq&pr=socks"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
How does the Internet Junkbuster work with SOCKS gateways?
</h3>
<p>
There is support for some
<a href="http://www.leverage.com/users/tlod/ssockd/ssockd.html">gateways</a>
in
Version <a href="ijbdist.html#c4">1.4</a>
and above.
The gateway protocol used to be specified on the command line;
it is
now specified
in the same file as
<a href="ijbman.html#forwardfile">forwarding.</a>
Note that the browser's proxy configuration must
<em>not</em>
specify a
<big><kbd>SOCKS</kbd></big>
host;
it should specify the proxy as described
<a href="ijbfaq.html#set">above.</a>
</p>

<h3><a name="plain" href="/cgi-bin/gp?pg=ijbfaq&pr=plain"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
How do I configure it to be just a plain old proxy?
</h3>
<p>
To get the proxy to do as little as possible (which means not deleting any
sensitive headers), place in your
configuration file the following three lines (each ending in a space
then a period) to stop it changing sensitive headers:
<br>
&#160;&#160;&#160;<big><kbd>referer .</kbd></big>
<br>
&#160;&#160;&#160;<big><kbd>from .</kbd></big>
<br>
&#160;&#160;&#160;<big><kbd>user-agent .</kbd></big>
<br>
&#160;&#160;&#160;<big><kbd>cookiefile mycookiefile</kbd></big>
<br>
The fourth line is also needed to specify a
<a href="ijbman.html#o_c">cookiefile</a>
that might be called
<big><kbd>mycookiefile</kbd></big>
containing a single line with a
<big><kbd>*</kbd></big>
character, to allow all cookies through.
</p>
<p align="center"><a href="#top_of_page"><img border=0 width=250 height=15 src="/images/top.gif" alt="--- Back to Top of Page ---"></a></p>
<br>
<center>
<h2><a name="companies"><font face="arial, helvetica">
Information for companies
</font></a>
</h2>
</center>
<br>
<h3><a name="think" href="/cgi-bin/gp?pg=ijbfaq&pr=think"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
What do advertising companies think of this kind of technology?
</h3>
<p>
We've seen only two public comment from the advertising industry on this.
First, the president of the Internet Advertising Bureau told
<a href="new.html#Rich">CNET</a>
that he wasn't worried by banner blockers.
Second, after the Federal Trade Commission's
<a href="ftc.html">workshop</a>
where we gave a live demonstration of our proxy before
many eminent representatives of the industry,
the
<a href="self.html#dma">Direct Marketing Association</a>
made the following
statement in the closing paragraphs
of their
<a href="http://www.ftc.gov/bcp/privacy2/comments2/dma027a.htm">summary comments</a>
to the Commission.
<blockquote>
Clever shareware developers have come up with products that
can obliterate cookies and advertisements for those consumers
who have these concerns.
The Internet is a market that is so democratic and flexible
that it is easy for companies and software
developers to respond to a perceived market need. 
</blockquote>
Their attitude seems to be that they would prefer that
people use technical solutions
to protect their privacy than have protections
imposed by legislation or government regulations.
So, do you perceive a market need?
Then here are some ways to flex your democratic muscles.
</p>

<h3><a name="nobrainer" href="/cgi-bin/gp?pg=ijbfaq&pr=nobrainer"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Should we provide the Internet Junkbuster for our employees?
</h3>
<p>
That depends. Try this quick three-point test.
<br><ol  type="1">
<li>
<a name="waste">Do you want to spend your communications budget</a>
on bandwidth that wastes your employees' time by forcing them to wait
for a lot of annoying distractions while they're trying to
do their jobs?
<li>
<a name="surveillance">Do you want current and potential vendors</a>
to know quantitative details about the
<a href="ijbfaq.html#agent">software and hardware platforms</a>
that you have?
<li>
<a name="intelligence">Do you want your competitors to be able to</a>
<a href="cookies.html">track</a>
exactly which of your
employees are checking out their web sites?
</ol>
If the answer to all three questions is yes,
then you probably don't have any need for this kind of product.
</p>

<h3><a name="commercial" href="/cgi-bin/gp?pg=ijbfaq&pr=commercial"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Can our company get commercial support for the software?
</h3>
<p>
Yes,
<a href="/cgi-bin/gp?pg=ijbfaq&pr=commercial">ask us</a>
for a quote on a maintenance contract with your choice of
phone and email support,
hard copy documentation,
source code and pre-compiled binaries on tape or disk,
and email alerting of upgrades and issues.
We also offer consulting services to help set up ``stealth browsing''
capabilities to help reduce the footprints left while doing competitive
analysis and other Web work where confidentiality is critical.
</p>

<h3><a name="isps" href="/cgi-bin/gp?pg=ijbfaq&pr=isps"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
I run an ISP. What issues should I consider before offering it?
</h3>
<p>
Many
<small>ISP</small>s
who offer the proxy to their customers have told us that
most of their customers are 
delighted with it
(although one reported that a customer complaint that without banner ads,
surfing was like reading a novel: we recommend making it optional).
Many
<small>ISP</small>s
like it because it reduces bandwidth requirements.
To help get you started,
here's a checklist we've developed from working with a few
<small>ISP</small>s.
You may think of more,
and we'd be interested if you're willing to
<a href="/cgi-bin/gp?pg=ijbfaq&pr=isps">share them</a>
with us.
<br><ol  type="1">
<li>
<a name="pending">If you get more than one request for</a>
the
Internet Junkbuster
you may want to tell your customers on your News page that you
<a href="ijbfaq.html#isp">already</a>
know about it and are assessing it.
<li>
<a name="try">Try the software and</a>
<a href="ijbfaq.html#install">verify</a>
that it performs satisfactorily.
<li>
<a name="value">Determine whether your customers perceive the service as</a>
<a href="ijbfaq.html#switch">valuable</a>
(and therefore worth the time to set up).
We've had reports of many delighted customers.
<li>
<a name="secure">Assess the</a>
level of
<a href="ijbfaq.html#others">security</a>
associated with the software.
If access is to be
<a href="ijbfaq.html#restrict">restricted</a>
(to just dial-in ports, for example)
how is this to be done?
<li>
<a name="costs">Consider</a>
whether to expect any additional load on computing resources required,
and any change in use of bandwidth due to the blocking of large
<small>GIF</small>s.
<li>
<a name="opt">Choose the</a>
<a href="ijbman.html">options</a>
you wish to provide.
<li>
<a name="multiple">Decide whether you want</a>
to offer a choice of configurations, such as these three.
<br><ol  type="A">
<li>
<a name="banner">Banners</a>
<a href="ijbfaq.html#blocking">Blocked,</a>
Wafer with
<a href="ijbfaq.html#notice">No-Cookie-Copyright</a>
notice
<li>
<a name="low">Cookies</a>
not stopped
(<a href="ijbman.html#cookiefile">cookiefile</a>
with just a
<big><kbd>*</kbd></big>
in it),
<a href="ijbfaq.html#header">User Agent</a>
specified as
<a href="ijbfaq.html#lynx">Lynx</a>
<li>
<a name="oneway">Cookies from browser</a>
<a href="ijbfaq.html#one">allowed</a>,
permitting
<a href="ijbfaq.html#registration">registered services</a>
<li>
<a name="kid">A proxy for</a>
<a href="ijbfaq.html#children">kids.</a>
</ol>
<a name="caching">If you run a</a>
<a href="ijbfaq.html#chain">caching proxy,</a>
decide whether the 
Internet Junkbuster
will chain with it by default,
and whether to offer an alternate with no caching.
(Some
<small>ISP</small>s
don't, because they want to give customers an incentive to use caching
and save bandwidth.)
<li>
<a name="naming">Decide on a naming scheme for your</a>
proxies.
If you're running only one
proxy on one machine,
the simplest way is to just use port 5865 on your main machine,
such as
<big><kbd>our-isp.net.</kbd></big>
But it would probably be safer to put an entry in your name server
and call it something like
<big><kbd>junkbuster.our-isp.net.</kbd></big>
If running several proxies, you could either use different ports
on the same machine, or if you have
the opportunity to distribute the load over
a few machines 
you could
use different hostname aliases such as
<big><kbd>banner.junkbuster.our-isp.net</kbd></big>,
<big><kbd>lynx.junkbuster.our-isp.net</kbd></big>
and
<big><kbd>oneway.junkbuster.our-isp.net</kbd></big>
(corresponding to the examples in the previous point).
You may want to set up
<a href="ijbfaq.html#Automatic">Automatic Proxy Configuration.</a>
<li>
<a name="document">Prepare a page</a>
explaining the
Internet Junkbuster
to your customers.
<a name="does">Here's are some examples from</a>
<a href="http://www.cia.com.au/us/junk.html">Australia</a>,
<a href="http://junkbuster.teclata.es/english/">Spain</a>,
<a href="http://www.rhein-ruhr.de/info/junkbuster.html">Germany</a>,
<a href="http://www.packet.net/ijb/">Florida</a>,
<a href="http://www.trip.net/junkbuster/">Texas</a>,
and
<a href="http://www.inconnect.com/proxy.html">Utah</a>.
<a name="reuse">You are welcome to copy and modify</a>
material
from
Junkbusters
according to the
<a href="gpl.html">GPL</a>.
You might want to set up a process to check this page periodically
and update it when it changes.
(A few links can probably serve as well as lot of copying however.)
A typical page would probably specify the following.
<br><ul  type="1">
<li>
<a name="abstract">A brief explanation stating what</a>
the
Internet Junkbuster
does, with a link to this page.
<li>
<a name="addresses">The addresses of the proxy or proxies,</a>
with their port number(s).
<li>
<a name="options">The options used,</a>
and how to view the contents of the blockfile (which you can place on
your web pages,
preferably in a file called
<big><kbd>blocklist.html</kbd></big>
or
<big><kbd>blocklist.txt</kbd></big>).
<li>
<a name="additions">An indication</a>
of whether suggestions for the blocklist are considered,
and if so, how to submit them: to a particular email address,
via web-based form, etc.
<li>
<a name="configuration">Instructions</a>
on how to
configure a browser.
You may want to include details for only the two major browsers
and leave the others to a link.
<li>
<a name="service">Procedures on how to report problems, give feedback etc.</a>
</ul>
<li>
<a name="beta">Invite a small number of technologically sophisticated</a>
customers to beta-test the service.
<li>
<a name="announce">Announce general availability on your ``News'' page.</a>
<a href="/cgi-bin/gp?pg=ijbfaq&pr=isps">Tell us</a>
if you would like to be included on a list of
<small>ISP</small>s
offering the
Internet Junkbuster.
</ol>
</p>

<h3><a name="ps2" href="/cgi-bin/gp?pg=ijbfaq&pr=ps2"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
What's a Proxy Server Server and how can I make money as one?
</h3>
<p>
Other organizations with web presence and some bandwidth to spare
can set up as
<i><dfn>Proxy Server Servers</dfn></i>
<!-- Aside: All this, and... -->
(<small>PS<sup>2</sup></small>s).
The idea here is to allow users to choose their proxy configuration,
and provide it to them on a semi-permanent basis.
Users would fill in a form specifying what options they want in
their proxy,
possibly even at a very high level, such as
``no ads''
or ``no nudity.''
This information is sent to a
<small>CGI</small>
script that
configures a proxy, starts it running, and returns its address and port number
(possibly along with configuration instructions for the browser
that the user specified.)
<p>
<a name="revenue">Users</a>
could be charged
a subscription fee,
or the service could be thrown in free in the hope of
improving customer retention for some existing business
(which is what
<small>ISP</small>s
are doing).
It might be possible to make money by
inserting new ads in the holes left where others were blocked,
but the original owners might object.
<small>PS<sup>2</sup></small>s
could differentiate themselves
by providing frequently updated and comprehensive
blocking of ads, or of offensive material based on their own grading system.
Some content providers might do it for the chance to be the
only company that the consumer permits to set cookies.
(Identification could even be done via cookies,
but this might not be popular with the kind of user who wants a proxy.)
<small>PS<sup>2</sup></small>s
might sell specific or aggregate information about their
users' browsing habits,
so the agreement with users on whether they are permitted to do this
would be important to both sides.
<p>
<a name="publicize">If your organization</a>
establishes a 
Proxy Server Service
you would like publicized,
please
<a href="/cgi-bin/gp?pg=ijbfaq&pr=publicize">notify us.</a>
</p>
<p align="center"><a href="#top_of_page"><img border=0 width=250 height=15 src="/images/top.gif" alt="--- Back to Top of Page ---"></a></p>
<br>
<center>
<h2><a name="blocking"><font face="arial, helvetica">
Blocking
</font></a>
</h2>
</center>
<br>
<h3><a name="readymade" href="/cgi-bin/gp?pg=ijbfaq&pr=readymade"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Where can I get an example blockfile that stops most ads?
</h3>
<p>
The sample blockfile we provide blocks almost nothing,
and we do not publish blockfiles that stop almost all banner ads.
But others have; you can find them by
<a href="http://altavista.digital.com/cgi-bin/query?pg=q&what=web&fmt=.&q=%2Bjunkbuster+%2Burl%3Ablocklist">asking Altavista.</a>
<a name="pub">(If you develop an interesting blocklist and publish it on the Web,</a>
you might want to include the word ``junkbuster'' in it
and use the word ``blocklist'' in the file name given in the
<small>URL</small>
so that others can find it with the query given in the previous sentence.)
</p>

<h3><a name="zap" href="/cgi-bin/gp?pg=ijbfaq&pr=zap"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
If I see an ad I wish I hadn't, how do I stop it?
</h3>
<p>
If your
<small>ISP</small>
is running the
Internet Junkbuster,
they should have a policy on whether they accept suggestions from
their customers on what to block. Consult their web page.
<p>
<a name="cover">If you are running</a>
the
Internet Junkbuster
yourself, you have complete control over what gets through.
Just add a pattern to cover the offending 
<small>URL</small>
to your blockfile.
Version 1.3 and later automatically rereads the blockfile when it changes,
but if you're running an earlier version
you'll need to
<big><kbd>kill</kbd></big>
it and
<a href="ijbfaq.html#restart">restart</a>
the
<b><kbd>junkbuster</kbd></b>.
<a name="pid">If you don't know the process number to give to</a>
<big><kbd>kill</kbd></big>, try this:
<big><kbd>ps ax | grep junkbuster</kbd></big>
<p>
<a name="target">To choose a pattern you'll first need to find the</a>
<small>URL</small>
of the ad you want cover.
<p>
<a name="pinpoint">Some people use the</a>
<a href="ijbman.html#debug">debug</a>
<big><kbd>1</kbd></big>
option to display each 
<small>URL</small>
in a window as the request is sent to the server.
It's then usually an easy task to pick the offending 
<small>URL</small>
from the list of recent candidates.
<p>
<a name="source">Alternatively,</a>
you can use
<b><font face="arial, helvetica">
View Document Info</font></b>
(or
<b><font face="arial, helvetica">
View Document Source</font></b>
if your browser doesn't have that).
The
<b><font face="arial, helvetica">
Info</font></b>
feature has the advantage of showing you the full
<small>URL</small>
including the host name,
which may not be specified in the source:
there you might see something like
<big><kbd>SRC="/ads/click_here_or_die.gif"</kbd></big>
indicating only the
<i><dfn>path</dfn></i>.
(The host name is assumed to be the same as the one the page came from.)
<p>
<a name="offsite">But ads often</a>
come from a different site, in which case you
might see something like
<big><kbd>SRC="grabem.n.trackem.com/Ad/Infinitum/SpaceID=1666"</kbd></big>
or longer.
<a name="warehouse">If the company looks like a pure ad warehouse</a>
(as in the last case),
you may want to place just its domain name in the blockfile,
which blocks all 
<small>URL</small>s
from that site.
<p>
<a name="wanted">If the ad comes from a server</a>
that you really want some content from,
you can include enough of the path
to avoid zapping stuff you might want.
In the first example above,
<big><kbd>/ads/</kbd></big>
would seem to be enough.
If you don't include the domain name,
the pattern applies to all sites,
so you don't want such patterns
to be too general:
for example
<big><kbd>/ad</kbd></big>
would block
<big><kbd>/admin/salaries/</kbd></big>
on your company's internal site.
<p>
<a name="image">To speed the blocking of images, some</a>
<small>UNIX <a href="legal.html#not_our_trademark">&#174;</a></small>
users create a
shell script called
<big><kbd>Image:</kbd></big>
containing a line such as
<big><kbd>echo $1 | sed s/http:..// &gt;&gt; $HOME/lib/blockfile</kbd></big>
that adds its argument to the user's blockfile.
Once an offending image has been be found using
<b><font face="arial, helvetica">
View Document Info</font></b>
it's easy to cut-and-paste the line (or part of it) into a shell window.
The same script can be linked to a file called
<big><kbd>Frame:</kbd></big>
to dealing with framed documents,
and
<big><kbd>junkbuster:</kbd></big>
to accept the output of the
<a href="ijbman.html#debug">debug</a>
option.
<p>
<a name="partial">When compiled without the</a>
<i><dfn>regular expressions</dfn></i>
option, the
Internet Junkbuster
uses only very simple (and fast) matching methods.
The pattern
<big><kbd>/banners</kbd></big>
will not stop
<big><kbd>/images/banners/huge.gif</kbd></big>
getting through: you would have to include the pattern
<big><kbd>/images/banners</kbd></big>
or something that matches in full from the left.
<a name="regex">So you can get what you want here,</a>
the matcher understands
<small>POSIX</small>
regular expressions:
you can use
<big><kbd>/*.*/banners</kbd></big>
to block
and any
<small>URL</small>
containing
<big><kbd>/banners</kbd></big>
(even in the middle of the path).
<a name="posix">(In Versions 1.1 through 1.4</a>
they were an option at compile time;
from Version 2.0 they have become the default.)
Regular expressions give you
<a href="http://theory.uwinnipeg.ca/localfiles/infofiles/gcc/rx_toc.html">many more features</a>
than this,
but if you're not already familiar with them you probably won't 
need to know anything beyond the
<big><kbd>/*.*/</kbd></big>
idiom.
If you do, a
<big><kbd>man egrep</kbd></big>
is probably a good starting point).
<p>
<a name="slash">Don't forget the</a>
<big><kbd>/</kbd></big>
(slash)
at the beginning of the path.
If you leave it out the line will be interpreted as a domain name,
so
<big><kbd>ad</kbd></big>
would block all sites from Andorra
(since
<big><kbd>.ad</kbd></big>
is the two-letter
<a href="reference.html#country">country code</a>
for that principality).
<p>
<a name="detail">For a detailed technical description</a>
of how pattern matching is done,
see the
<a href="ijbman.html#o_b">manual.</a>
</p>

<h3><a name="despite" href="/cgi-bin/gp?pg=ijbfaq&pr=despite"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
How come this ad is still getting through anyway?
</h3>
<p>
If the ad had been displayed before you included its
<small>URL</small>
in the blockfile,
it will probably be held in cache for some time,
so it will be displayed without the need for any request to the server.
Using the
<a href="ijbman.html#debug">debug</a>
<big><kbd>1</kbd></big>
option to show each
<small>URL</small>
as it is fetched is a good way to see exactly what is happening.
<p>
<a name="otherwise">If new items seem to be getting through,</a>
check that you are
<a href="ijbfaq.html#show">really running</a>
the proxy with the right blockfile in the options.
Check the blockfile for
<a href="ijbfaq.html#exceptions">exceptions.</a>
<p>
<a name="java">Some sites may have different ways of inserting ads,</a>
such as via
<a href="cookies.html#java">Java.</a>
If you have ideas on how to block new kinds
of junk not currently covered, please
<a href="/cgi-bin/gp?pg=ijbfaq&pr=java">tell us.</a>
</p>

<h3><a name="exceptions" href="/cgi-bin/gp?pg=ijbfaq&pr=exceptions"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
How do I stop it blocking a URL that I actually want?
</h3>
<p>
You can change the patterns so they don't cover it,
or use a simple feature in Version 1.1 and later: a line beginning with a
<big><kbd>~</kbd></big>
character means that a
<small>URL</small>
blocked by previous patterns that matches the rest of
the line is let through.
For example,
the pattern
<big><kbd>/ad</kbd></big>
would block
<big><kbd>/addasite.html</kbd></big>
but not if followed by
<big><kbd>~/addasite</kbd></big>
in the blockfile.
Or suppose you want to see everything that comes from
a site you like, even if it looks like an ad: simply put
<big><kbd>~aSiteYouLike.com</kbd></big>
at the
<em>end</em>
of the blockfile.
(Order is important, because the last matching line wins.)
<p>
<a name="agreed">As well as unblocking</a>
pages that were unintentionally blocked,
this feature is useful for unblocking ads from a specific source.
This might be because you are interested in those particular ones,
or if you have an explicit agreement to accept certain ads,
such as those from a free web-based email provider.
</p>

<h3><a name="children" href="/cgi-bin/gp?pg=ijbfaq&pr=children"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Can I block sites I don't want my children to see?
</h3>
<p>
Yes, but remember that
<a name="savvy">children who are technically sophisticated enough</a>
to use the browsers' proxy configuration options
could of course bypass any proxy.
This kind of technology can be used as a gentle barrier to remind
or guide the child,
but nobody should expect it to replace the parent's role
in setting and enforcing standards of online behavior for their children.
<p>
<a name="recommend">Some</a>
<small>ISP</small>s
are starting to provide specialized proxies to protect children.
There are two basic approaches: the ``black list'' and the ``white list''
approach.
<a name="negative">The black list approach allows the child</a>
to go anywhere not explicitly prohibited; the white list permits visits
only to sites explicitly designated as acceptable.
<p>
<a name="positive">It's very easy for</a>
anyone to
compile a white list from a page of ``recommended
kids sites'' and to configure an
Internet Junkbuster
to restrict access to those sites.
If you compile with the
<a href="ijbfaq.html#regex">regex</a>
option,
you can place a
<big><kbd>*</kbd></big>
(asterisk) as the first line of the blockfile (which blocks everything),
and then list
<a href="ijbfaq.html#exceptions">exceptions</a>
after that.
Be careful to make the exception sufficiently broad:
for example, using
<big><kbd>~www.uexpress.com/ups/comics/ch/</kbd></big>
as the exception for
<a href="http://www.uexpress.com/ups/comics/ch/"><cite>Calvin and Hobbes</cite></a>
would block some of the graphic elements on the page;
you would probably want a wider exception such as
<big><kbd>~www.uexpress.com/ups/</kbd></big>
to permit them.
<p>
<a name="trust">Version 2.0 has an experimental feature</a>
to permit only sites mentioned in a nominated
<a href="ijbman.html#trustfile">trusted site.</a>
<p>
<a name="scan">Many filtering</a>
<a href="links.html#blocking">products</a>
actually scan for keywords in
the text of pages they retrieve
before presenting it,
but
the
Internet Junkbuster
does not do this.
Building a perfectly reliable black list system is hard,
because it's very difficult to state
in advance
exactly
what is obscene or unsuitable.
</p>

<h3><a name="message" href="/cgi-bin/gp?pg=ijbfaq&pr=message"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
What do I see when a page or graphic is blocked by the proxy?
</h3>
<p>
You usually see a broken image icon,
but it depends on several factors beyond the proxy's control.
If asked for a
<small>URL</small>
matching its blockfile, the proxy returns an
<small>HTML</small>
page containing a message identifying itself
(currently the two words ``Internet Junkbuster'')
with a status 202 (Accepted) instead of the usual 200 (OK).
(Versions 1.X returned an error 404: Forbidden, which caused
strange behavior in some cases.)
Status 202 is described
<small>HTTP</small>
<a href="http://www.ics.uci.edu/pub/ietf/http/rfc1945.html#Code202">RFC</a>
as indicating that the request has been accepted but not completed,
and that it might complete successfully in the future
(in our case, if the blockfile were changed).
<p>
<a name="depends">The broken image icon is most common</a>
because the browser is usually expecting a graphic.
But if it was expecting text, or if the page happens to be using certain
<small>HTML</small>
extensions
such as
<big><kbd>layer</kbd></big>
and your browser is a late model from Microsoft,
you may see the words ``Internet Junkbuster'' displayed as a hot link.
<p>
<a name="click">Clicking on the link takes you to an explanation of</a>
the pattern in the blockfile that caused the block,
so that you can edit the blockfile and go back and reload if you really
want to see what was blocked. The explanatory link is generated by
the proxy and is automatically intercepted based on its ending in
<big><kbd>ij-blocked-url</kbd></big>;
even though the site is specified as
<big><kbd>http://internet.junkbuster.com</kbd></big>
no request is actually made to that site.
<p>
<a name="layer">To summarize:</a>
the identifying link to the blocking explanation
is usually turned into a broken image icon,
but it may be displayed on a page alone,
or they may may be restricted to the particular frame, layer or graphic area
specified in the page containing them.
The proxy has no way of knowing the context in which a
<small>URL</small>
will be used and cannot control how the blocking message will be rendered.
</p>

<h3><a name="broken" href="/cgi-bin/gp?pg=ijbfaq&pr=broken"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Why not replace blocked banners with something invisible?
</h3>
<p>
<a name="infringe">Many users have suggested to us</a>
that blocked banners should be replaced by a something like a
1x1 transparent
<small>GIF</small>
to make the page would look as if there was nothing ever there.
Apart from making it harder to catch unintended blocking,
this might also displease the owners of the page,
who could argue that such a change constitutes a copyright infringement.
We think that merely failing to allow an included graphic to be accessed
would probably not be considered an infringement:
after all this is what happens when a browser
is configured not to load images automatically.
However, we are
<a href="over.html#notlaw">not</a>
lawyers,
so anyone in doubt should take appropriate advice.
<p>
<a name="done">In a context where the copyright issue is resolved</a>
satisfactorily,
a proxy could simply return a status 301 or 302 and
specify a replacement
<small>URL</small>
in a
<big><kbd>Location</kbd></big>
and/or
<big><kbd>URI</kbd></big>
header.
An alternative would be to use inline code to return a
1 x 1 clear
<small>GIF</small>.
We do not publish sample code for this,
and we have no way of stopping
<a href="ijbdist.html#others">others</a>
who have.
</p>

<h3><a name="size" href="/cgi-bin/gp?pg=ijbfaq&pr=size"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Why not block banners based on the dimensions of the image?
</h3>
<p>
Many users have pointed out that most banner ads come in standard sizes,
so why not block all
<small>GIF</small>s
of those sizes?
This would theoretically be without fetching the object 
because the dimensions are usually given in the
<big><kbd>IMG</kbd></big>
tag,
but it would require substantial changes in the code,
and we doubt whether it would be much more effective than a good block list.
</p>

<h3><a name="embedded" href="/cgi-bin/gp?pg=ijbfaq&pr=embedded"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
What about non-graphic advertising within the pages I want?
</h3>
<p>
The
Internet Junkbuster
deliberately
does not provide a way of automatically editing the contents of a page,
to remove textual advertising or
to repair the holes left by blocked banners.
Other packages such as
<a href="links.html#webfilter">WebFilter</a>
do.
<p>
<a name="base">For the same reason,</a>
it has no way of stopping a new browser
window being created, because this is done through the
<big><kbd>target</kbd></big>
attribute in the
<big><kbd>&lt;a&gt;</kbd></big>
and
<big><kbd>&lt;base&gt;</kbd></big>
elements,
not through headers.
</p>

<h3><a name="push" href="/cgi-bin/gp?pg=ijbfaq&pr=push"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Does it block ads on the new broadcasting ``push'' systems?
</h3>
<p>
We haven't tried it though we expect it would probably
work on image ads on push channels.
If you find you have experience using the proxy with push,
or have any other advice about it, please
<a href="/cgi-bin/gp?pg=ijbfaq&pr=push">tell us.</a>
</p>
<p align="center"><a href="#top_of_page"><img border=0 width=250 height=15 src="/images/top.gif" alt="--- Back to Top of Page ---"></a></p>
<br>
<center>
<h2><a name="cookies"><font face="arial, helvetica">
Cookies
</font></a>
</h2>
</center>
<br>
<h3><a name="breakthrough" href="/cgi-bin/gp?pg=ijbfaq&pr=breakthrough"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Might some cookies still get through? How can I stop them?
</h3>
<p>
Yes, you should expect the occasional cookie to make it through to your browser.
We know of at least three ways this can happen;
please
<a href="/cgi-bin/gp?pg=ijbfaq&pr=breakthrough">tell us</a>
if you find any others.
One way is in secure documents, which are explained
<a href="ijbfaq.html#secure">below.</a>
<p>
<a name="EQUIV">A</a>
<a href="links.html#JavaScript">few</a>
sites set cookies using a line such as
<big><kbd>&lt;META HTTP-EQUIV="Set-Cookie" CONTENT="flavor=chocolate"&gt;</kbd></big>
in the
<big><kbd>HEAD</kbd></big>
section of an
<small>HTML</small>
document.
<a name="javascript">Cookies can also be</a>
<!-- IEM: http://cgi.netscape.com/eng/mozilla/Gold/handbook/javascript/ref_a-c.html#cookie_property -->
set and read
in
JavaScript.
To see if this is happening in a document,
view its source, look in the
<big><kbd>head</kbd></big>
for a section tagged
<big><kbd>script language="JavaScript"</kbd></big>.
If it contains a reference to
<big><kbd>document.cookie</kbd></big>,
the page can manipulate your cookie file without sending any cookie headers.
The
Internet Junkbuster
does not tamper with these methods.
Fortunately they are rarely used at the moment.
<p>
<a name="alert">To prevent cookies breaking through,</a>
<strong>always</strong>
keep
<a href="cookies.html#disable">cookie alerts</a>
turned on in your browser,
and
<a href="cookies.html#java">disable</a>
Java and Javascript.
Making the files
<a href="cookies.html#only">hard to write</a>
may also help.
</p>

<h3><a name="method" href="/cgi-bin/gp?pg=ijbfaq&pr=method"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Exactly how do cookies get created and stored anyway?
</h3>
<p>
When a web site's server sends you a page it also sends
certain ``header information'' which your browser records but does not display.
One of these is a
<big><kbd>Set-Cookie</kbd></big>
header, which specifies the cookie information that the server wants your browser to record.
Similarly, when your browser requests a page it also sends headers, specifying
information such as the graphics formats it understands.
If a cookie has previously been set by a site that matches the
<small>URL</small>
it is about to request,
your browser adds a
<big><kbd>Cookie</kbd></big>
header quoting the previous information.
<p>
<a name="privacy">For more background information on how cookies</a>
can damage your privacy, see our
<a href="cookies.html">page on cookies.</a>
For highly detailed technical information see the
<a href="links.html#kristol">RFC.</a>
The
Internet Junkbuster
will show you all headers you use the
<a href="ijbman.html#debug">debug</a>
<big><kbd>8</kbd></big>
option,
or you can get a sample from our
<a href="ijbfaq.html#headers">demonstration page.</a>
</p>

<h3><a name="break" href="/cgi-bin/gp?pg=ijbfaq&pr=break"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
If cookies can't get through, will some things stop working for me?
</h3>
<p>
Possibly.
Some personalized services including certain
<!-- IEM: http://my.yahoo.com -->
chat
rooms
require cookies.
<a name="registration">Newspapers that require</a>
<!-- IEM: http://www.nytimes.com/subscribe/sub-bin/new_sub.cgi#agree -->
registration
or
<!-- IEM: http://interactive5.wsj.com/regUser.html -->
subscription
will not automatically recognize you if you don't send them the cookie they
assigned you. And there are a very small number of sites that do
strange things with cookies; they don't work for anyone that blocks
cookies by any means.
Some sites such as
<a href="http://support.microsoft.com/register/register.asp">Microsoft</a>
explain that their content is so wonderfully compelling that
they will withhold it from you unless you submit to their
inserting cookies.
<p>
<a name="want">If you want such sites to be given your cookies,</a>
you can use the
<a href="ijbman.html#cookiefile">cookiefile</a>
option provided you are running
<a href="ijbfaq.html#crumble">Version 1.2 or later</a>
yourself.
Simply include the domain name of those sites in the
<i>cookiefile</i>
specified by this option.
<p>
<a name="one">It's possible to let cookies out but not in,</a>
which is enough to keep some sites happy, but not all of them:
one newspaper site seems to go into an endless frenzy
if deprived of fresh cookies.
A cookiefile containing
a single line consisting of the two characters
<big><kbd>&gt;*</kbd></big>
(greater-than and star) permits server-bound cookies only.
The
<big><kbd>*</kbd></big>
is a
<a href="ijbman.html#wildcard">wildcard</a>
that matches all domains.
<p>
<a name="else">If someone else is running the</a>
Internet Junkbuster
for you and has a version
that
<!-- IAM: ijbfaq.html#registration -->
passes server-bound cookies through,
you can try editing your browser's cookie
file to contain just the ones you want,
and restart your browser.
<a name="window">To subscribe to a new service like this</a>
after you have started using the
Internet Junkbuster,
you can try the following:
tell your browser to
<a href="ijbfaq.html#discontinue">stop using</a>
the
Internet Junkbuster,
fill out and submit your subscription details
(allowing that web site to set a cookie),
then
reconfigure your browser to use the
Internet Junkbuster
again
(and stop more cookies being sent).
This also requires the
<a href="ijbman.html#cookiefile">cookiefile</a>
option,
and its success depends on the Web site
not wanting to change your cookies at every session.
For this reason it does not work at some major newspaper sites, for example.
<a name="buyers">But you may prefer to</a>
look at whether other sites provide the same
or better services without demanding the opportunity
to track your behavior.
The web is a buyer's market where most prices are zero:
very few people pay
for content with money, so why should you pay with your privacy?
</p>

<h3><a name="crumble" href="/cgi-bin/gp?pg=ijbfaq&pr=crumble"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Can I control cookies on a per-site basis?
</h3>
<p>
<a name="discard">Yes, since version 1.2 the</a>
Internet Junkbuster
has included advanced cookie management facilities.
Unless you specify otherwise,
cookies are discarded (``crumbled'') by the
Internet Junkbuster
whether they came from the server or the browser.
In Version 1.2 and later you can
use the
<a href="ijbman.html#cookiefile">cookiefile</a>
option
to specify when cookies are to be passed through intact.
It uses the same syntax and
<a href="ijbman.html#o_b">matching</a>
algorithm as the blockfile.
<p>
<a name="cook">If the</a>
<small>URL</small>
matches a pattern in the
<i><dfn>cookiefile</dfn></i>
then cookies are let through in both the browser's request for the
<small>URL</small>
and in the server's response.
<a name="directional">One-way permissions can be</a>
specified by starting the line with the
<big><kbd>&gt;</kbd></big>
or
<big><kbd>&lt;</kbd></big>
character.
For example, a cookiefile consisting of the four lines
<br>
&#160;&#160;&#160;<big><kbd>org</kbd></big>
<br>
&#160;&#160;&#160;<big><kbd>&gt;send-user-cookies.org</kbd></big>
<br>
&#160;&#160;&#160;<big><kbd>&lt;accept-server-cookies.org</kbd></big>
<br>
&#160;&#160;&#160;<big><kbd>~block-all-cookies.org</kbd></big>
<br>
allows cookies to and from
<big><kbd>.org</kbd></big>
domains only, with the following exceptions:
<br><ol  type="1">
<li>
<a name="fed">Cookies sent from servers in the domain</a>
<big><kbd>send-user-cookies.org</kbd></big>
are blocked on their way to the client,
but cookies sent by the browser to that domain are still be fed to them.
<li>
<a name="take">The cookies of</a>
<big><kbd>accept-server-cookies.org</kbd></big>
check in to the proxy and are passed through to the browser,
but when they come back to the proxy they never check out.
<li>
<a name="deny">All cookies to and from</a>
<big><kbd>block-all-cookies.org</kbd></big>
are blocked.
</ol>
<p>
<a name="paths">If</a>
the
<b><kbd>junkbuster</kbd></b>
was compiled with the regular expressions option
they may be used in paths.
Any logging to a
<a href="ijbfaq.html#jar">``cookie jar''</a>
is separate and not affected.
<p>
<a name="breadth">It's important to give hosts you want to be able</a>
to set cookies sufficient breadth. For example,
instead of
<big><kbd>www.wsj.com</kbd></big>
use
<big><kbd>wsj.com</kbd></big>
because the company uses many different hosts ending in that domain.
</p>

<h3><a name="wafers" href="/cgi-bin/gp?pg=ijbfaq&pr=wafers"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Can I make up my own fake cookies (wafers) to feed to servers?
</h3>
<p>
Yes,
using the
<a href="ijbman.html#wafer">wafer</a>
option.
We coined the term
<i><dfn>wafer</dfn></i>
to describe cookies chosen by a user,
not the Web server.
Servers may not find wafers as tasty as the cookies
they make themselves.
But users may enjoy controlling servers' diets for various reasons,
such as the following.
<br><ul  type="1">
<li>
<a name="retaliate">Users who consider cookies to</a>
be an unwelcome intrusion and a waste
of their disk space can respond in kind.
By writing ``signature wafers'' they can
express their feelings about cookies,
in a place that the people
in charge of them are most likely to notice.
<li>
<a name="notice">Sites running a proxy</a>
that logs cookies to a file
(such as the
Internet Junkbuster
does with the
<a href="ijbman.html#jarfile">jarfile</a>
option on)
may want to notify
servers that their cookies are being intercepted,
deleted or copied.
One possible reason for doing this is the uncertain copyright status
of cookie strings.
<a href="over.html#notlaw">Nothing</a>
here should be taken as legal advice: we are simply raising a question
for any interested parties to consider,
and make no representation that such measures are necessary or sufficient.
Concerned proxy sites might decide to send a wafer
(named ``NOTICE'' for example)
containing text along the lines of the following.
<blockquote>
<p>
<a name="licenses_on_cookies_refused">TO WHOM IT MAY CONCERN</a>
<i>
<br>
<br>
Do not send me any copyrighted information other than the
document that I am requesting or any of its necessary components.
<br>
<br>
In particular do not send me any cookies that
are subject to a claim of copyright by anybody.
Take notice that I refuse to be bound by any license condition
(copyright or otherwise) applying to any cookie.
</i>
</blockquote>
Any company that tries to argue in court that the proxy site
was breaching their copyright in the cookies would
be met with the defense that the proxy site gave that company
the opportunity to protect its copyright by simply
not sending cookies after receiving the notice. 
<p>
<a name="pointer">Cookies can be as long as four thousand characters,</a>
so there's plenty of space for lawyerly verbosity,
but white space, commas, and semi-colons are
<a href="ijbman.html#o_w">prohibited.</a>
Spaces can be turned into underscores.
Alternatively,
a
<small>URL</small>
could be sent as the cookie value,
pointing to a document containing a notice,
perhaps with a suggestive value such as
<br>
<big><kbd>http://www.junkbusters.com/ht/en/ijbfaq.html#licenses_on_cookies_refused</kbd></big>
<br>
But including the notice directly would probably be preferable
because the addressee does not have to look it up.
<p>
<a name="vanilla">The</a>
Internet Junkbuster 2.0
currently sends a full notice as a
``vanilla wafer''
if cookies are being logged to a cookie jar.
This can be suppressed with the
<a href="ijbman.html#suppress-vanilla-wafer">suppress-vanilla-wafer</a>
option,
which might be used in situations where there is an established understanding
between the proxy and all who serve it.
</ul>
<p>
<a name="gimme">Junkbusters provides a</a>
<small>CGI</small>
script that lets you
<a href="ijbfaq.html#headers">see</a>
your wafers as they appear to servers.
<p>
<a name="malfunction">Wafers confuse a few fragile servers.</a>
If this troubles you, don't use this option.
<p>
<a name="regardless">Any wafers specified are sent to</a>
all sites regardless of the cookiefile.
<a name="compliant">They are appended after genuine cookies,</a>
to maintain compliance with
<a href="links.html#kristol">RFC 2109</a>
in the event that a path was specified for a cookie.
The
<small>RFC</small>'s provisions regarding the
<big><kbd>$</kbd></big>
character
(such as the
<big><kbd>Version</kbd></big>
attribute)
are transparent
to the proxy; it simply quotes what was recited by the browser.
<p>
<a name="personalize">If you want to send wafers only to specific sites,</a>
you could try putting them your browser's cookie file in a format
conforming to the Netscape
<a href="links.html#netscape">specification</a>,
and then specify in the proxy's cookiefile that cookies are to be
<a href="ijbfaq.html#directional">sent to</a>
but not accepted from those sites, so they can't overwrite the file.
This may work with Netscape but not all other browsers.
</p>

<h3><a name="jar" href="/cgi-bin/gp?pg=ijbfaq&pr=jar"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Why would anyone want to save their cookies in a ``cookie jar?''
</h3>
<p>
We provided this capability just in case anyone wants it.
There are a few possible reasons.
<br><ul  type="1">
<li>
<a name="pay">It's conceivable that</a>
marketing companies might one day
<a href="new.html#hagel">buy</a>
history files and cookie jars from consumers
in the same way that they currently pay them to fill out survey forms.
With this information they could
gather psychographic information,
see which competitors' sites the consumer has visited,
and discover what advertising is being targeted at them.
<li>
<a name="choose">Some consumers might</a>
employ semi-automated means of sorting through
their cookie jars, selecting which ones to place in their cookies
file for use by their browsers.
Their decisions could be based on payments offered,
privacy rating systems such as
<a href="links.html#truste">TRUSTe</a>
proposes,
or their own opinion of the company.
It could be done manually or with software.
<li>
<a name="share">Users may even start ``sharing'' cookies among themselves,</a>
sending back cookies that servers generated for other visitors.
Servers that aren't expecting this possibility
will be misled about their visitors' identities.
Cookies could be shared among users on a single machine,
or across continents via
<small>FTP</small>
and anonymous remailers.
<a name="disinformation">Privacy activists may promote</a>
cookie disinformation campaigns
as a way to defend the public against abuse.
If a significant percentage of people send disinformative cookies,
user tracking via cookies may become less reliable and less used.
</ul>
</p>
<p align="center"><a href="#top_of_page"><img border=0 width=250 height=15 src="/images/top.gif" alt="--- Back to Top of Page ---"></a></p>
<br>
<center>
<h2><a name="anonymity"><font face="arial, helvetica">
Anonymity
</font></a>
</h2>
</center>
<br>For details
on how your identity can be revealed while you surf,
see our page on
<a href="http://www.junkbusters.com/cgi-bin/privacy">privacy.</a>
Once you start using
the
Internet Junkbuster
you should find that much of the information
previously indicated on that page will no longer be provided.
We also recommend that you
<a href="cookies.html">disable JavaScript</a>
and
<a href="links.html#java">Java.</a>

<h3><a name="disclose" href="/cgi-bin/gp?pg=ijbfaq&pr=disclose"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
If I use the Internet Junkbuster, will my anonymity be guaranteed?
</h3>
<p>
No. Your chances of remaining anonymous are improved,
but unless you are an expert on Internet security
it would be safest to assume that everything you do on the Web
can be attributed to you personally.
<p>
<a name="happen">The</a>
Internet Junkbuster
removes various information about you,
but it's still possible that web sites can find out who you are.
Here's one way this can happen.
<p>
<a name="ftp">A few browsers</a>
<a href="http://www.junkbusters.com/cgi-bin/privacy">disclose the user's email address</a>
in certain situations, such as when transferring a file by
<small>FTP</small>.
The
Internet Junkbuster 2.0
does not filter the
<small>FTP</small>
stream.
If you need this feature, or are concerned about the mail handler
of your browser disclosing your email address,
you might consider
products such as
<a href="links.html#nsclean">NSClean</a>.
<p>
<a name="binaries">Browsers downloaded as binaries</a>
could use non-standard headers to give out any information
they can have access to: see the manufacturer's license agreement.
It's impossible to anticipate and prevent every breach of privacy that
might occur.
The professionally paranoid prefer browsers available as source code,
because anticipating their behavior is easier.
</p>

<h3><a name="header" href="/cgi-bin/gp?pg=ijbfaq&pr=header"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
What private information from server-bound headers is removed?
</h3>
<p>
The
Internet Junkbuster
pounces on the following
<small>HTTP</small>
headers in requests to servers,
unless instructed otherwise in the options.
<br><ul  type="1">
<li>
<a name="from">The</a>
<big><kbd>FROM</kbd></big>
header,
which a few browsers use to tell your email address to servers,
is dropped
unless the
<a href="ijbman.html#from">from</a>
option is set.
<li>
<a name="agent">The</a>
<big><kbd>USER_AGENT</kbd></big>
<a name="infer">header</a>
is changed to indicate that the browser is
currently Mozilla (Netscape) 3.01 Gold
with an unremarkable Macintosh configuration.
Misidentification helps resist certain
<a href="ijbfaq.html#misidentify">attacks.</a>
(Earlier versions of the
Internet Junkbuster
indicated different details;
by changing them periodically we aim to hinder anyone trying to
<a href="ijbfaq.html#detect">infer</a>
whether our proxy is present.)
<a name="lying">If you don't like the idea</a>
of incorrectly identifying your computer as a Mac,
set it accordingly.
<!-- Aside: or read Kundera's Unbearable Lightness of Being, 5:5, ``It is a tragicomic fact..'' (p187?) -->
<li>
<a name="referer">The</a>
<big><kbd>REFERER</kbd></big>
header
(which indicates where the
<small>URL</small>
currently being requested was found)
is dropped.
A single static referer to replace all
real referers may be specified using the 
<a href="ijbman.html#referer">referer</a>
option.
Where no referer is provided by the browser, none is added;
the
<a href="ijbman.html#add-header">add-header</a>
option with arguments such as
<big><kbd>-x 'Referer: http://me.me.me'</kbd></big>
can be used to send a bogus referer with every request.
</ul>
In 
Version <a href="ijbdist.html#c4">1.4</a>
and later you can use the
<a href="ijbman.html#o_r">-r @</a>
option to selectively disclose
<big><kbd>REFERER</kbd></big>
and
<big><kbd>USER_AGENT</kbd></big>
to only those sites you nominate.
<p>
<a name="UA">Some browsers</a>
send Referer and User-Agent information under different non-standard headers.
The
Internet Junkbuster 2.0
stops
<big><kbd>UA</kbd></big>
headers,
but others may get through.
<a name="indexers">Some search engines</a>
<a href="cookies.html#queries">encode the query you typed</a>
in the
<small>URL</small>
that goes to advertisers to target a banner ad at you,
so you will need to block the ad as well as the referer header,
unless you want them (and anyone they might
<a href="cookies.html#set">buy data</a>
from)
to know
<a href="links.html#search">everything you ever search for.</a>
<p>
<a name="JavaScript">If you have JavaScript enabled (the default on</a>
most browsers) servers can use it to obtain Referer and User Agent,
as well as your plug-ins.
We recommend
<a href="cookies.html#java">disabling</a>
JavaScript and Java.
</p>

<h3><a name="breakage" href="/cgi-bin/gp?pg=ijbfaq&pr=breakage"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Might some things break because header information is changed?
</h3>
<p>
Possibly.  If used with a browser less advanced than Netscape 3.0 or IE-3,
indicating an advanced browser
may encourage pages containing extensions that confuse your browser.
If this becomes a problem
upgrade your browser or
use the
<a href="ijbman.html#user-agent">user-agent</a>
option to indicate an
<a href="ijbfaq.html#low">older browser.</a>
In 
Version <a href="ijbdist.html#c4">1.4</a>
 and later you can selectively reveal your real browser
to only those sites you nominate.
<p>
<a name="counters">Some</a>
<a href="http://www.yahoo.com/Computers_and_Internet/Internet/World_Wide_Web/Programming/Access_Counts/">page access counters</a>
work by looking at the referer;
they may fail or break when deprived.
<p>
<a name="wired">Some sites depend on getting a referer header,</a>
such as
<big><kbd>uclick.com</kbd></big>,
which serves comic strips
for many newspaper sites,
including
<a href="http://www.uclick.com/?feature=db"><cite>Doonsbury</cite></a>
for the
<a href="http://www.washingtonpost.com/wp-srv/style/longterm/comics/comics.htm"><cite>Washington Post.</cite></a>
(If you click on that last link, you can then get to a page containing
the strip via the
same
<small>URL</small>
we've linked to under
<cite>Doonsbury</cite>,
but if you click on the
<cite>Doonsbury</cite>
link directly, it gives you an error message suggesting that you
use a browser that supports referers.)
In 
Version <a href="ijbdist.html#c4">1.4</a>
 and later you can use the
<a href="ijbman.html#o_r">-r @</a>
option
and place a line like
<big><kbd>&gt;uclick.com</kbd></big>
in your cookiefile.
<a href="http://www.wired.com/news/">Wired News</a>
used to use referer to decide whether to add a navigation column to
the page, but they have changed that.
<p>
<a name="Intellicast">The weather maps of</a>
<a href="links.html#Intellicast">Intellicast</a>
have been blocked by their server when no referer or cookie is provided.
You can use the same countermeasure with a line such as
<big><kbd>&gt;208.194.150.32</kbd></big>
(or simply get your weather information
<a href="ijbfaq.html#buyers">elsewhere</a>).
<p>
<a name="decide">Some software vendors, including</a>
<a href="http://www.intuit.com/quicken_store/">Intuit</a>
use
<big><kbd>USER_AGENT</kbd></big>
to decide which versions of their products to display to you.
With the
<a href="ijbfaq.html#agent">default</a>
you get Mac versions.
<p>
<a name="What">We have had reports that on some versions of Netscape the</a>
<a href="http://home.netscape.com/home/whats-new.html">What's New</a>
feature does not work with the proxy,
but we have not been able to reproduce this problem.
If you can figure out what's happening, please
<a href="/cgi-bin/gp?pg=ijbfaq&pr=What">tell us.</a>
</p>

<h3><a name="misidentify" href="/cgi-bin/gp?pg=ijbfaq&pr=misidentify"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
How is misidentifying my browser good for security and privacy?
</h3>
<p>
Almost
<a href="new.html#Browser">every</a>
major release of both leading browsers has contained
bugs that allow malicious servers to compromise your privacy and security.
Known bugs are quickly fixed, but millions of copies of the affected
software remain out there, and yours is probably one of them.
The
<a href="ijbfaq.html#agent">header</a>
that normally identifies your browser tells such servers exactly which attacks
to use against you.
By misidentifying your browser you reduce the likelihood that they
will be able to mount a successful attack.
</p>

<h3><a name="conceal" href="/cgi-bin/gp?pg=ijbfaq&pr=conceal"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Does the Internet Junkbuster conceal my IP address?
</h3>
<p>
Yes, assuming the proxy is running on a machine with a different IP address.
Unless the
<a href="ijbman.html#forwardfile">forwardfile</a>
option is used, the remote server gets only the IP address of the proxy,
not its client.
If this address is too close for comfort
you can use the
<a href="ijbman.html#forwardfile">forwardfile</a>
option to set up a chain of proxies,
but this makes browsing slower of course.
<a name="anonymizing">One public proxy that you can</a>
forward to is
<a href="new.html#LPWA">lpwa.com</a>
port 8000.
Read about its privacy-enhancing
features and the authentication procedures first,
and note that it blocks
<a href="ijbfaq.html#wired">referer</a>
in almost all cases,
as well as some
<a href="http://lpwa.com:8000/system.html#principles:header">other headers.</a>
</p>

<h3><a name="ident" href="/cgi-bin/gp?pg=ijbfaq&pr=ident"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Does the Internet Junkbuster thwart identification by identd?
</h3>
<p>
We think so,
provided you are not the user running the
proxy.
If your computer (or your
<small>ISP</small>'s)
is running the
<a href="links.html#identd"><kbd>identd</kbd></a>
demon,
servers can ask it for the identity of the
user making the request at time you request a page from them.
But if you're going through a proxy,
they will identify the user name associated with the proxy, not you.
A visit to
<a href="http://ident.junkbusters.com">http://ident.junkbusters.com</a>
lets you see what's happening.
This test is (quite rightly) blocked by many
<a href="ijbfaq.html#firewall">firewalls;</a>
just interrupt the transfer if you get an abnormal wait after clicking.
Running other applications
may also expose you via
<a href="links.html#identd"><kbd>identd</kbd></a>;
the proxy of course doesn't help then.
</p>

<h3><a name="detect" href="/cgi-bin/gp?pg=ijbfaq&pr=detect"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Can web sites tell that I'm using the Internet Junkbuster?
</h3>
<p>
With the default options the proxy doesn't announce itself.
Obvious indications such as
<a href="links.html#alive">Keep-Alive</a>
headers are
<a href="ijbman.html#o_x">deleted,</a>
but sites might notice that you can cancel cookies faster than
any human could possibly click on a mouse.
(If you want to provide a
plausible explanation for this,
change the User Agent header to a
<a href="ijbfaq.html#lynx">cookie-free</a>
or
<a href="cookies.html#communicator">cookie-crunching</a>
browser).
<p>
<a name="figure">But when certain options</a>
are used they could figure out something's going on,
even if they're not pushing cookies.
If you use blocking
they can tell from their logs that the graphics in their pages
are not being requested selectively.
The
<a href="ijbman.html#add-forwarded-header">add-forwarded-header</a>
option explicitly announces to the server that a proxy is present,
and
sending them
<a href="ijbfaq.html#wafers">wafers</a>
is of course a dead giveaway.
</p>
<p align="center"><a href="#top_of_page"><img border=0 width=250 height=15 src="/images/top.gif" alt="--- Back to Top of Page ---"></a></p>
<br>
<center>
<h2><a name="security"><font face="arial, helvetica">
Security
</font></a>
</h2>
</center>
<br>
<h3><a name="encrypt" href="/cgi-bin/gp?pg=ijbfaq&pr=encrypt"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
What happens with Secure Documents (SSL, https:)?
</h3>
<p>
If you enter a
``Secure Document Area,''
cookies and other header information
such as User Agent and Referer
are sent encrypted,
so they cannot be filtered.
We recommend getting your browser to alert you when this happens.
(On Netscape:
<b><font face="arial, helvetica">
Options</font></b>;
<b><font face="arial, helvetica">
Security</font></b>;
<b><font face="arial, helvetica">
General</font></b>;
<b><font face="arial, helvetica">
Show an alert before entering a secure document space</font></b>.) 
<p>
<a name="passage">It may be possible to filter encrypted cookies</a>
by combining the blocking proxy with a cryptographic proxy along
the lines of
<a href="http://stronghold.ukweb.com/safepassage/">SafePassage</a>,
but we have not tried this.
</p>

<h3><a name="ssl" href="/cgi-bin/gp?pg=ijbfaq&pr=ssl"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Will using this as my Security Proxy compromise security?
</h3>
<p>
We're not security experts, but we don't think so.
The whole point of
<small>SSL</small>
is that the
contents of messages are
<!-- IEM: http://addy.com/dc/html/what_is_ssl_.html -->
encrypted
by the time
they leave the browser and the server.
Eavesdroppers (including proxies) can see where your messages are going
whether you are running a proxy or not,
but they only get to see the contents after they have been encrypted.
</p>

<h3><a name="restrict" href="/cgi-bin/gp?pg=ijbfaq&pr=restrict"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Can I restrict use of the proxy to a set of nominated IP addresses?
</h3>
<p>
Yes, we added an
<a href="ijbman.html#aclfile">access control</a>
file in Version 2.0.
But before you use it please consider why you want to do it.
If the reason is security,
it probably means you need a firewall.
<p>
<a name="selective">The</a>
<a href="ijbman.html#listen-address">listen-address</a>
option provides a way of binding the proxy to a single IP address/port.
The right way to do this is to choose a port inside your firewall, and
deny access to it to those outside the firewall.
The
Internet Junkbuster
is not a firewall proxy;
it should not be expected to solve security problems.
<p>
<a name="firewall">For background information on firewalls,</a>
see
<a href="http://www.yahoo.com/Computers_and_Internet/Security_and_Encryption/Firewalls/">Yahoo</a>
or these well-known books:
<a href="http://www.amazon.com/exec/obidos/ISBN=0201633574/junkbusterscomA/"><cite>Firewalls and Internet Security: Repelling the Wily Hacker</cite></a>
by
<person>William R. Cheswick</person>
and
<person>Steven M. Bellovin</person>
or
<a href="http://www.amazon.com/exec/obidos/ISBN=1565921240/junkbusterscomA/"><cite>Building Internet Firewalls</cite></a>
by
<person>D. Brent Chapman</person>
<person>Elizabeth D. Zwicky</person>.
There's
<a href="http://www.wmd.de/wmd/staff/pauck/misc/fwtk_on_linux.html">free Linux software</a>
available,
and a large number of
<a href="http://www.yahoo.com/Business_and_Economy/Companies/Computers/Software/System_Utilities/Security/Firewalls/">commercial</a>
products and services.
For an excellent security overview, primer, and compendium reference, see
<a href="http://www.amazon.com/exec/obidos/ISBN=1565921488/junkbusterscomA/"><cite>Practical Unix and Internet Security</cite></a>
by
<person>Simson Garfinkel</person>
and
<person>Gene Spafford</person>.
</p>

<h3><a name="others" href="/cgi-bin/gp?pg=ijbfaq&pr=others"><img border=0 width=14 height=14 src="/images/fb.gif" alt="*"></a>&#160;
Are there any security risks for ISPs or others who offer the proxy?
</h3>
<p>
Yes.
As with any service offered over the Internet,
hackers can try to misuse it.
A well-run
<small>ISP</small>
will have professionals who are experienced at assessing and containing
these risks.
<p>
<a name="outside">It's possible to set up your machine so</a>
that other people can have access to your proxy,
but if you lack expertise in computer security
you probably shouldn't have your computer configured to offer
this or any other service to the outside world.
<p>
<a name="attack">Hackers can attempt to gain access</a>
to the machine by various attacks,
which we have tried to guard against but don't guarantee to thwart.
They can also use the ``anonymizing'' quality of proxies
to try to cover their tracks while hacking other computers.
For this reason we recommend preventing it being used
as an anonymous
<big><kbd>telnet</kbd></big>,
by including the pattern
<big><kbd>:23</kbd></big>
in the blockfile.
(Actually the current implementation incidentally blocks telnet due to the
way headers are handled, but it's best not to rely on this.)
If you wish to block all ports except the default
<small>HTTP</small>
port 80,
you can put the lines
<br>
&#160;&#160;&#160;<big><kbd>:</kbd></big>
<br>
&#160;&#160;&#160;<big><kbd>~:80</kbd></big>
<br>
at the beginning of the blockfile, but be aware that some servers
run on non-default ports (e.g. 5865). You might also want to add the line
<big><kbd>~:443</kbd></big>
to allow
<small>SSL</small>.
<p>
<a name="holes">If you find any security holes in the code</a>
please
<a href="/cgi-bin/gp?pg=ijbfaq&pr=holes">tell us,</a>
along with any suggestions you may have for fixing it.
However, we do not claim that we will be able to do so.
<p>
<a name="useful">We distribute this code in the hope that people</a>
will find it useful, but we provide
<a href="ijbfaq.html#free">no warranty</a>
for it,
and we are not responsible for anyone's use or misuse of it.
<p>
<a name="updates">You may also want to check back periodically for updated versions of the code.</a>
We do not
maintain a mailing list.
To get quick updates, bookmark our
<a href="ijbdist.html#versions">Distribution Information</a>
page.
</p>
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