.TH JUNKBUSTER 1 "http://www.junkbusters.com/ht/en/ijb2.0man.html"
.SH NAME
\fBjunkbuster\fP
- The
Internet Junkbuster
Proxy
\s-2(TM)\s+2
.SH SYNOPSIS
\fBjunkbuster\fP
\fI\&configfile\fP
(Version 2.0 onwards)
.br
\fBjunkbstr.exe\fP
\fI\&configfile\fP
(Windows)
.br
\fBjunkbuster\fP
[-a]
[-y]
[-s]
[-c]
[-v]
.br
[-u user_agent]
[-r referer]
[-t from]
.br
[-b blockfile]
[-j jarfile]
[-l logfile]
.br
[-w NAME=VALUE]
[-x Header_text]
.br
[-h [bind_host_address][:bind_port]]
.br
[-f forward_host[:port]]
[-d N]
.br
[-g gw_protocol[:[gw_host][:gw_port]]]
.br
(Version 1.4 and earlier)
.SH DESCRIPTION
\fBjunkbuster\fP
is an instrumentable proxy that filters the 
\s-2HTTP\s0
stream between
web servers and browsers.
Its main purpose is to enhance privacy.
.P
Versions before 2.0 used command-line options;
Versions from 2.0 on use a configuration file.
The following descriptions of the options first give the older
command-line usage, then the new configfile line.
.P
In Versions 2.0.1 upwards on Windows
a start-up message is printed and the file
\fC\&junkbstr.ini\fP
is read as the configuration if it exists and no argument was given.
.P
All files except the configfile
are checked for changes before each page is fetched,
so they can may edited without restarting the proxy.
.SS OPTIONS
.TP
.\" anchor: o_b blockfile
\fI-b blockfile\fP (Old) blockfile \fIblockfile\fP (New)
Block\" ijbfaq.html#blocking
requests to
\s-2URL\s0s
matching any pattern given in the lines of the
\fI\&blockfile\fP.
The
\fBjunkbuster\fP
instead returns status 202, indicating that the request has been accepted
(though not completed),
and a
message identifying itself\" ijbfaq.html#show
(though the browser may
display only a broken image icon).
(Versions before 2.0 returned an error 403 (Forbidden).)
The syntax of a pattern is
\fB\&[domain][:port][/path]\fP
(the
\fB\&http://\fP
or
\fB\&https://\fP
protocol part is omitted).
To decide if a pattern matches a target, the domains are compared first,
then the paths. 
.P
To compare the domains,
the pattern domain and the target
domain specified in the
\s-2URL\s0
are each broken into their components.
(Components are separated by the
\fC\&.\fP
(period) character.)
Next each of the target components
is compared with the corresponding pattern component: last with last,
next-to-last with next-to-last, and so on.
(This is called
\fIright-anchored\fP
matching.)
If all of the pattern components find their match in the target,
then the domains are considered a match.
Case is irrelevant when comparing domain components.
.P
A successfully
matching pattern can be an anchored substring of a target, but
not vice versa.
Thus if a pattern doesn't specify a domain,
it matches all domains.
.\" anchor: wildcard
Furthermore, when comparing two components,
the components must either match in their entirety or up to a wildcard
\fC\&* \fP
(star character) in the pattern.  The wildcard feature
implements only a "prefix" match capability ("abc*" vs. "abcdefg"),
not suffix matching ("*efg" vs. "abcdefg") or
infix matching ("abc*efg" vs. "abcdefg").
The feature is restricted to the domain component;
it is unrelated to the optional
regular expression
feature in the path
(described below).\" ijbman.html#regex
.P
If a numeric port
is specified in the pattern domain, then the target port must
match as well.  The default port in a target is port 80.
.P
If the domain and port match,
then the target
\s-2URL\s0
path is checked for
a match against the path in the pattern.
Paths are compared with a simple case-sensitive
left-anchored substring comparison.
Once again, the pattern can be an
anchored substring of the target, but not vice versa.
A path of
\fC\&/\fP
(slash) would match all paths.  Wildcards are not considered in
path comparisons.
.P
For example, the target
\s-2URL\s0
.br
.ti +0.25i
\fB\&the.yellow-brick-road.com/TinMan/has_no_brain\fP
.br
would be matched (and blocked) by the following patterns
.br
.ti +0.25i
\fB\&yellow-brick-road.com\fP
.br
and
.br
.ti +0.25i
\fB\&Yellow*.COM\fP
.br
and
.br
.ti +0.25i
\fB\&/TinM\fP
.br
but not
.br
.ti +0.25i
\fB\&follow.the.yellow-brick-road.com\fP
.br
or
.br
.ti +0.25i
\fB\&/tinman\fP
.br
.P
Comments in a blockfile start with a
\fB\&#\fP
(hash) character and end at a new line.
Blank lines are also ignored.
.P
Lines beginning with a
\fC\&~\fP
(tilde) character are taken to be
exceptions:\" ijbfaq.html#exceptions
a
\s-2URL\s0
blocked by previous patterns that matches the rest of
the line is let through. (The last match wins.)
.P
Patterns
may contain
\s-2POSIX\s0
regular expressions\" ijbfaq.html#regex
provided the
\fBjunkbuster\fP
was compiled with this option
(the default in Version 2.0 on).
The idiom
\fC\&/*.*/ad\fP
can then be used
to match any
\s-2URL\s0
containing
\fC\&/ad\fP
(such as
\fC\&http://nomatterwhere.com/images/advert/g3487.gif\fP
for example).
.P
In version 1.3 and later
the blockfile and cookiefile are checked for changes before each request.
.TP
tinygif \fIN\fP
Set appearance of blocked GIFs. You can select one of the following
values:
.br
.br
\h'-\w"0 = "u'0 = Show a ``broken icon'' in the browser
.br
\h'-\w"1 = "u'1 = Show a one pixel transparent GIF
.br
\h'-\w"2 = "u'2 = Show a GIF with the word ``JUNKBUSTER'' in it
.TP
imagefile \fIimagefile\fP
Define a file which holds regular expressions which tell junkbuster
whether a URL points to an image. This is needed if tinygif is set to
1 or 2, so junkbuster can decide whether to display a GIF or to show a 
html page with a link which tells the user why this page is blocked.
.TP
.\" anchor: o_w wafer
\fI-w NAME=VALUE\fP (Old) wafer \fINAME=VALUE\fP (New)
Specifies a pair to be sent as a cookie with every request
to the server.\" ijbfaq.html#wafers
(Such boring cookies are called
\fI\&wafers\fP.)
This option may be called more than once to generate multiple wafers.
The original
Netscape specification\" ijbman.html#netscape
prohibited
semi-colons, commas and white space;
these characters will be
\s-2URL\s0-encoded
if used in wafers.
The Path and Domain attributes are not currently supported.
.TP
.\" anchor: o_c cookiefile
\fI-c cookiefile\fP (Old) cookiefile \fIcookiefile\fP (New)
Enforce the cookie management policy specified in the
\fI\&cookiefile.\fP
.\" anchor: java
If this option is not used all cookies are silently crunched,
so that users who never want cookies aren't bothered by browsers
asking whether each cookie should be accepted.
However, cookies can
still get through\" ijbfaq.html#breakthrough
via
JavaScript\" links.html#javascript
and
\s-2SSL\s0,
so alerts should be left on.
.P
In Version 1.2 and later
this option must be followed by a
filename\" ijbfaq.html#crumble
containing instructions on which sites are allowed to
receive and set cookies.
.\" anchor: drop
By default cookies are dropped in both the browser's request
and the server's response, unless the
\s-2URL\s0
requested matches an entry in the
\fI\&cookiefile\fP.
The matching algorithm is the same as for the blockfile.
A leading
\fC\&>\fP
character allows
server-bound\" ijbfaq.html#directional
cookies only;
a
\fC\&<\fP
allows only browser-bound cookies;
a
\fC\&~\fP
character stops cookies in
both directions.\" ijbfaq.html#crumble
Thus a cookiefile containing a single line with the two characters
\fC\&>*\fP
will pass on all cookies to servers but not give any new ones to the browser.
.TP
.\" anchor: o_j jarfile
\fI-j jarfile\fP (Old) jarfile \fIjarfile\fP (New)
All Set-cookie attempts by the server are
logged\" ijbfaq.html#jar
to
\fI\&jarfile\fP.
If no wafer is specified,
one containing a
canned notice\" ijbfaq.html#notice
(the 
\fI\&vanilla wafer\fP)
is added as an alert to the server
unless the
suppress-vanilla-wafer\" ijbman.html#suppress-vanilla-wafer
option is invoked.
.TP
.\" anchor: o_v suppress-vanilla-wafer
\fI-v\fP (Old) suppress-vanilla-wafer \fI\fP (New)
Suppress the vanilla wafer.
.TP
.\" anchor: o_t from
\fI-t from\fP (Old) from \fIfrom\fP (New)
If the browser
discloses an email address\" ijbfaq.html#from
in the
\fB\&FROM\fP
header (most don't),
replace it with
\fI\&from.\fP
If
\fI\&from\fP
is set to
\fB\&.\fP
(the period character)
the
\fB\&FROM\fP
is passed to the server unchanged.
The default is to delete the
\fB\&FROM\fP
header.
.TP
.\" anchor: o_r referer
\fI-r referer\fP (Old) referer \fIreferer\fP (New)
Whenever the browser discloses the
\s-2URL\s0
that
led to\" ijbfaq.html#referer
the current request,
replace it with
\fI\&referer.\fP
If
\fI\&referer\fP
is set to
\fB\&.\fP
(period)
the 
\s-2URL\s0
is passed to the server unchanged.
In 
Version 1.4
 and later, if referer is set to 
\fB\&@\fP
(at) the
\s-2URL\s0
is sent in cases where the cookiefile
specifies that a cookie would be sent.
(No way to send bogus referers selectively is provided.)
The default is to delete Referer.
.P
Version 2.0 also accepts the spelling
\fC\&referrer\fP,
which most dictionaries consider correct.
.TP
.\" anchor: o_u user-agent
\fI-u user-agent\fP (Old) user-agent \fIuser-agent\fP (New)
Information disclosed by the browser
about itself\" ijbfaq.html#agent
is replaced with the value
\fI\&user-agent.\fP
If
\fI\&user-agent\fP
is set to
\fB\&.\fP
(period)
the
\fB\&User-Agent\fP
header is passed to the server unchanged,
along with any
\fB\&UA\fP
headers produced by
\s-2MS-IE\s0
(which would otherwise be deleted).
In 
Version 1.4
 and later, if
\fI\&user-agent\fP
is set to
\fB\&@\fP
(at) these headers are sent unchanged in cases where the cookiefile
specifies that a cookie would be sent,
otherwise only default
\fB\&User-Agent\fP
header is sent.
That default
is Mozilla/3.0 (Netscape)
with an unremarkable
Macintosh\" ijbfaq.html#infer
configuration.
If used with a browser less advanced than Mozilla/3.0 or IE-3, the default
may encourage pages containing extensions that confuse the browser.
.TP
.\" anchor: o_h listen-address
\fI-h [host][:port]\fP (Old) listen-address \fI[host][:port]\fP (New)
If
\fI\&host\fP
is specified,
bind the
\fBjunkbuster\fP
to that
\s-2IP\s0
address.
The default is to bind to all 
\s-2IP\s0
addresses
(\fB\&INADDR_ANY\fP).
Specifying a
\fI\&port\fP
is optional;
the default is 5865.
.TP
.\" anchor: o_f forwardfile
\fI-f forward_host[:port]\fP (Old) forwardfile \fIforwardfile\fP (New)
Version 1.X required all
\s-2HTTP\s0
requests from the client to be forwarded to the same destination.
Version 2.0 takes its routing specification from a
\fI\&forwardfile\fP,
allowing selection of the proxy (a.k.a. forwarding host) and gateway
according to the
\s-2URL\s0.
Here is a typical line.
.br
.ft CW
.S 8
.nf
.sp
*         lpwa.com:5865      .      .
.S
.ft
.fi
.sp

.P
Each line contains four fields:
\fB\&target\fP,
\fB\&forward_to\fP,
\fB\&via_gateway_type\fP
and
\fB\&gateway\fP.
As usual, the
last\" ijbman.html#compare
\fB\&target\fP
domain that matches the requested
\s-2URL\s0
wins,
and the
\fC\&*\fP
character alone matches any domain.
If the winning
\fB\&forward_to\fP
field is
\fC\&.\fP
(the dot character) the proxy connects 
directly to the server given in the
\s-2URL\s0,
otherwise it forwards to the host and port number specified.
The default port is 5865.
The
\fC\&via_gateway_type\fP
and
\fC\&gateway\fP
fields also use a dot to indicate no gateway protocol.
The gateway protocols are explained
below.\" ijbman.html#o_g
.P
The example line above in a forwardfile alone
would send everything through port 5865 at
\fC\&lpwa.com\fP
with no gateway protocol,
and is equivalent to the old
\fC\&-f lpwa.com:5865\fP
with no
\fC\&-g\fP
option.
For more information see the example file provided with the distribution.
.P
Configure with care: no loop detection is performed.
When setting up chains of proxies that might loop back, try adding
Squid.\" ijbman.html#squid
.TP
.\" anchor: o_g 
\fI-g gw_protocol[:[gw_host][:gw_port]]\fP (Old) 
Use
\fI\&gw_protocol\fP
as the gateway protocol.
This option was introduced in Version 1.4,
but was folded into the
forwardfile\" ijbman.html#forwardfile
option in Version 2.0.
The default is to use no gateway protocol;
this may be explicitly specified as
\fB\&direct\fP
on the command line
or the dot character in the forwardfile.
The
\fC\&SOCKS4\fP
protocol may be specified as
\fB\&socks\fP
or
\fB\&socks4\fP.
The
\fC\&SOCKS4A\fP
protocol is specified as
\fB\&socks4a\fP.
The
\fC\&SOCKS5\fP
protocol is not currently supported.
The default
\s-2SOCKS\s0
\fI\&gw_port\fP
is 1080.
.P
The user's browser should
\fInot\fP
be
configured\" ijbfaq.html#socks
to use
\fC\&SOCKS\fP;
the proxy conducts the negotiations, not the browser.
.P
The user identification capabilities of
\fC\&SOCKS4\fP
are deliberately not used;
the user is always identified to the
\fC\&SOCKS\fP
server as
\fC\&userid=anonymous\fP.
If the server's policy is to reject requests from
\fC\&anonymous\fP,
the proxy will not work.
Use a
debug\" ijbman.html#o_d
value of 3
to see the status returned by the server.
.TP
.\" anchor: o_d debug
\fI-d N\fP (Old) debug \fIN\fP (New)
Set debug mode.
The most common value is 1,
to
pinpoint\" ijbfaq.html#pinpoint
offensive
\s-2URL\s0s,
so they can be added to the blockfile.
The value of
\fB\&N\fP
is a bitwise
logical-\s-2OR\s0
of the following values:
.br
.br
\h'-\w"1 = "u'1 = URLs (show each URL requested by the browser);
.br
\h'-\w"2 = "u'2 = Connections (show each connection to or from the proxy);
.br
\h'-\w"4 = "u'4 = I/O (log I/O errors);
.br
\h'-\w"8 = "u'8 = Headers (as each header is scanned, show the header and what is done to it);
.br
\h'-\w"16 = "u'16 = Log everything (including debugging traces and the contents of the pages).
.\" anchor: or
Multiple
\fB\&debug\fP
lines are permitted; they are logical OR-ed together.
.P
Because most browsers send several requests in parallel
the debugging output may appear intermingled, so the
single-threaded\" ijbman.html#single-threaded
option is recommended when using
debug\" ijbman.html#debug
with
\fB\&N\fP
greater than 1.
.TP
.\" anchor: o_y add-forwarded-header
\fI-y\fP (Old) add-forwarded-header \fI\fP (New)
Add 
\fB\&X-Forwarded-For\fP
headers to the server-bound 
\s-2HTTP\s0
stream
indicating the client 
\s-2IP\s0
address
to the server,\" ijbfaq.html#detect
in the new style of
Squid 1.1.4.\" ijbman.html#squid
.TP
.\" anchor: o_x add-header
\fI-x HeaderText\fP (Old) add-header \fIHeaderText\fP (New)
Add the
\fI\&HeaderText\fP
verbatim to requests to the server.
Typical uses include
adding old-style forwarding notices such as
\fB\&Forwarded: by http://pro-privacy-isp.net\fP
and reinstating the
\fB\&Proxy-Connection: Keep-Alive\fP
header
(which the
\fBjunkbuster\fP
deletes so as
not\" ijbfaq.html#detect
to reveal its existence).
No checking is done for correctness or plausibility,
so it can be used to throw any old trash into the server-bound 
\s-2HTTP\s0
stream.
Please don't litter.
.TP
.\" anchor: o_s single-threaded
\fI-s\fP (Old) single-threaded \fI\fP (New)
Doesn't
\fB\&fork()\fP
a separate process
(or create a separate thread)
to handle each connection.
Useful when debugging to keep the process single threaded.
.TP
.\" anchor: o_l logfile
\fI-l logfile\fP (Old) logfile \fIlogfile\fP (New)
Write all debugging data into
\fI\&logfile.\fP
The default
\fI\&logfile\fP
is the standard output.
.TP
.\" anchor: o_acl aclfile
aclfile \fIaclfile\fP (New)
Unless this option is used, the proxy talks to anyone who can connect to it,
and everyone who can has equal permissions on where they can go.
An access file allows restrictions to be placed on these two policies,
by distinguishing some
\fIsource\fP
\s-2IP\s0
addresses and/or
some
\fIdestination\fP
addresses.
(If a
forwarder or a gateway\" ijbman.html#forwardfile
is being used, its address is considered the destination address,
not the ultimate
\s-2IP\s0
address of the
\s-2URL\s0
requested.)
.P
Each line of the access file begins with
either the word
\fB\&permit\fP
or
\fB\&deny\fP
followed by source and (optionally) destination addresses 
to be matched against those of the
\s-2HTTP\s0
request.
The last matching line specifies the result: if it was a
\fB\&deny\fP
line or if no line matched,
the request will be refused.
.P
A source or destination
can be specified as a single numeric
\s-2IP\s0
address,
or with a hostname, provided that the host's name
can be resolved to a numeric address: this cannot be used to block all
\fB\&.mil \fP
domains for example,
because there is no single address associated with that domain name.
Either form may be followed by a slash and an integer
\fB\&N\fP,
specifying a subnet mask of
\fB\&N\fP
bits.
For example,
\fB\&permit 207.153.200.72/24\fP
matches the entire Class-C subnet from
207.153.200.0
through 207.153.200.255.
(A netmask of 255.255.255.0 corresponds to 24 bits of
ones in the netmask, as with
\fC\&*_MASKLEN=24\fP.)
A value of 16 would be used for a Class-B subnet.
A value of zero for
\fB\&N\fP
in the subnet mask length will cause any address to match;
this can be used to express a default rule.
For more information see the example file provided with the distribution.
.P
If you like these access controls
you should probably have
firewall;\" ijbfaq.html#firewall
they are not intended to replace one.
.TP
.\" anchor: o_tf trustfile
trustfile \fItrustfile\fP (New)
This feature is experimental, has not been fully documented and is
very subject to change.
The goal is for parents to be able to choose a page or site whose
links they regard suitable for their
young children\" ijbfaq.html#children
and for the proxy to allow access only to sites mentioned there.
To do this the proxy examines the
referer\" ijbman.html#o_r
variable on each page request to check they resulted from
a click on the ``trusted referer'' site: if so the referred site
is added to a list of trusted sites, so that the child can
then move around that site.
There are several uncertainties in this scheme that experience may be
able to iron out; check back in the months ahead.
.TP
.\" anchor: o_ti trust_info_url
trust_info_url \fItrust_info_url\fP (New)
When access is denied due to lack of a trusted referer, this
\s-2URL\s0
is displayed with a message pointing the user to it for further information.
.TP
.\" anchor: o_hc hide-console
hide-console \fI\fP (New)
In the Windows version only, instructs the program
to disconnect from and hide the command console after starting.
.TP
.\" anchor: o_a 
\fI-a\fP (Old) 
(Obsolete) Accept the server's
\fB\&Set-cookie\fP
headers, passing them through to the browser.
.\" anchor: obsolete
This option was removed in Version 1.2
and replaced by an improvement to the
-c\" ijbman.html#o_c
option.
.LE
.SH INSTALLATION AND USE
Browsers must be told where to find the
\fBjunkbuster\fP
(e.g.
\fB\&localhost\fP
port 5865).
To set the 
\s-2HTTP\s0
proxy in Netscape 3.0,
go through:
\fB\&Options\fP;
\fB\&Network Preferences\fP;
\fB\&Proxies\fP;
\fB\&Manual Proxy Configuration\fP;
\fB\&View\fP.
See the
\s-2FAQ\s0
for other browsers.
The
Security Proxy\" ijbfaq.html#security
should also be set to the same values,
otherwise
\fB\&shttp:\fP
\s-2URL\s0s
won't work.
.P
Note the limitations
explained in the
\s-2FAQ\s0.
.SH CHECKING OPTIONS
To allow users to
check\" ijbfaq.html#show
that a
\fBjunkbuster\fP
is running and how it is configured,
it intercepts requests for any
\s-2URL\s0
ending in
\fB\&/show-proxy-args\fP
and blocks it,
returning instead returns information on its
version number and
current configuration
including the contents of its blockfile.
To get an explicit warning that no
\fBjunkbuster\fP
intervened if the proxy was not configured,
it's best to point it to a
\s-2URL\s0
that does this, such as
http://internet.junkbuster.com/cgi-bin/show-proxy-args
on Junkbusters's website.
.SH SEE ALSO
http://www.junkbusters.com/ht/en/ijbfaq.html\" ijbfaq.html#
.br
http://www.junkbusters.com/ht/en/cookies.html\" cookies.html#
.br
http://internet.junkbuster.com/cgi-bin/show-proxy-args
.br
http://www.netscape.com/newsref/std/cookie_spec.html
.br
http://www.ds.internic.net/rfc/rfc2109.txt
.br
http://squid.nlanr.net/Squid/
.br
http://www-math.uni-paderborn.de/~axel/
.SH COPYRIGHT AND GPL
Written and copyright by the Anonymous Coders and Junkbusters Corporation
and made available under the
GNU General Public License (GPL).\" gpl.html#
This software comes with
NO WARRANTY.\" gpl.html#nowarr
Internet Junkbuster
is a trademark of Junkbusters Corporation.