3 By: Junkbuster Developers
5 $Id: user-manual.sgml,v 1.35 2002/03/05 00:17:27 hal9 Exp $
7 The user manual gives the users information on how to install and configure
8 Internet Junkbuster. Internet Junkbuster is an application that provides
9 privacy and security to users of the World Wide Web.
11 You can find the latest version of the user manual at http://
12 ijbswa.sourceforge.net/user-manual/.
14 Feel free to send a note to the developers at <
15 ijbswa-developers@lists.sourceforge.net>.
17 -------------------------------------------------------------------------------
33 3. Invoking and Configuring JunkBuster
35 3.1. Command Line Options
36 3.2. The Main Configuration File
38 3.2.1. Defining Other Configuration Files
39 3.2.2. Other Configuration Options
40 3.2.3. Access Control List (ACL)
42 3.2.5. Windows GUI Options
46 3.3.1. URL Domain and Path Syntax
53 4. Quickstart to Using Junkbuster
54 5. Contacting the Developers, Bug Reporting and Feature Requests
55 6. Copyright and History
63 8.1. Regular Expressions
67 Internet Junkbuster is a web proxy with advanced filtering capabilities for
68 protecting privacy, filtering and modifying web page content, managing cookies,
69 controlling access, and removing ads, banners, pop-ups and other obnoxious
70 Internet Junk. Junkbuster has a very flexible configuration and can be
71 customized to suit individual needs and tastes. Internet Junkbuster has
72 application for both stand-alone systems and multi-user networks.
74 This documentation is included with the current BETA version of Internet
75 Junkbuster and mostly complete at this point. The most up to date reference for
76 the time being is still the comments in the source files and in the individual
77 configuration files. Development of version 3.0 is currently nearing
78 completion, and includes many significant changes and enhancements over earlier
79 versions. The target release date for stable v3.0 is "soon" ;-)
81 Since this is a BETA version, not all new features are well tested. This
82 documentation may be slightly out of sync as a result. And there may be bugs,
83 though hopefully not many!
85 -------------------------------------------------------------------------------
89 In addition to Junkbuster's traditional features of ad and banner blocking and
90 cookie management, this is a list of new features currently under development:
92 * Integrated browser based configuration and control utility (http://i.j.b).
93 Browser-based tracing of rule and filter effects.
95 * Modularized configuration that will allow for system wide settings, and
96 individual user settings. (not implemented yet, probably a 3.1 feature)
98 * Blocking of annoying pop-up browser windows.
100 * HTTP/1.1 compliant (most, but not all 1.1 features are supported).
102 * Support for Perl Compatible Regular Expressions in the configuration files,
103 and generally a more sophisticated and flexible configuration syntax over
108 * Web page content filtering (removes banners based on size, invisible
109 "web-bugs", JavaScript, pop-ups, status bar abuse, etc.)
111 * Bypass many click-tracking scripts (avoids script redirection).
113 * Multi-threaded (POSIX and native threads).
115 * Auto-detection and re-reading of config file changes.
117 * User-customizable HTML templates (e.g. 404 error page).
119 * Improved cookie management features (e.g. session based cookies).
121 * Builds from source on most UNIX-like systems. Packages available for: Linux
122 (RedHat, SuSE, or Debian), Windows, Sun Solaris, Mac OSX, OS/2.
124 * In addition, the configuration is much more powerful and versatile
127 -------------------------------------------------------------------------------
131 Junkbuster is available as raw source code, or pre-compiled binaries. See the
132 Junkbuster Home Page for current release info. Junkbuster is also available via
133 CVS. This is the recommended approach at this time. But please be aware that
134 CVS is constantly changing, and it may break in mysterious ways.
136 -------------------------------------------------------------------------------
140 For gzipped tar archives, unpack the source:
142 tar xzvf ijb_source_* [.tgz or .tar.gz]
143 cd ijb_source_2.9.10_beta
146 For retrieving the current CVS sources, you'll need the CVS package installed
147 first. To download CVS source:
149 cvs -d:pserver:anonymous@cvs.ijbswa.sourceforge.net:/cvsroot/ijbswa login
150 cvs -z3 -d:pserver:anonymous@cvs.ijbswa.sourceforge.net:/cvsroot/ijbswa co current
154 This will create a directory named current/, which will contain the source
157 Then, in either case, to build from tarball/CVS source:
159 ./configure (--help to see options)
160 make (the make from gnu, gmake for *BSD)
162 make -n install (to see where all the files will go)
163 make install (to really install)
166 For Redhat and SuSE Linux RPM packages, see below.
168 -------------------------------------------------------------------------------
172 To build Redhat RPM packages, install source as above. Then:
174 autoheader [suggested for CVS source]
175 autoconf [suggested for CVS source]
180 This will create both binary and src RPMs in the usual places. Example:
182 /usr/src/redhat/RPMS/i686/junkbuster-2.9.11-1.i686.rpm
184 /usr/src/redhat/SRPMS/junkbuster-2.9.11-1.src.rpm
186 To install, of course:
188 rpm -Uvv /usr/src/redhat/RPMS/i686/junkbuster-2.9.11-1.i686.rpm
191 This will place the Junkbuster configuration files in /etc/junkbuster/, and log
192 files in /var/log/junkbuster/.
194 -------------------------------------------------------------------------------
198 To build SuSE RPM packages, install source as above. Then:
200 autoheader [suggested for CVS source]
201 autoconf [suggested for CVS source]
206 This will create both binary and src RPMs in the usual places. Example:
208 /usr/src/packages/RPMS/i686/junkbuster-2.9.11-1.i686.rpm
210 /usr/src/packages/SRPMS/junkbuster-2.9.11-1.src.rpm
212 To install, of course:
214 rpm -Uvv /usr/src/packages/RPMS/i686/junkbuster-2.9.11-1.i686.rpm
217 This will place the Junkbuster configuration files in /etc/junkbuster/, and log
218 files in /var/log/junkbuster/.
220 -------------------------------------------------------------------------------
224 Junkbuster is packaged in a WarpIN self- installing archive. The
225 self-installing program will be named depending on the release version,
226 something like: ijbos2_setup_1.2.3.exe. In order to install it, simply run this
227 executable or double-click on its icon and follow the WarpIN installation
228 panels. A shadow of the Junkbuster executable will be placed in your startup
229 folder so it will start automatically whenever OS/2 starts.
231 The directory you choose to install Junkbuster into will contain all of the
234 If you would like to build binary images on OS/2 yourself, you will need a few
235 Unix-like tools: autoconf, autoheader and sh. These tools will be used to
236 create the required config.h file, which is not part of the source distribution
237 because it differs based on platform. You will also need a compiler. The
238 distribution has been created using IBM VisualAge compilers, but you can use
239 any compiler you like. GCC/EMX has the disadvantage of needing to be
240 single-threaded due to a limitation of EMX's implementation of the select()
243 In addition to needing the source code distribution as outlined earlier, you
244 will want to extract the os2seutp directory from CVS:
246 cvs -d:pserver:anonymous@cvs.ijbswa.sourceforge.net:/cvsroot/ijbswa login
247 cvs -z3 -d:pserver:anonymous@cvs.ijbswa.sourceforge.net:/cvsroot/ijbswa co os2setup
250 This will create a directory named os2setup/, which will contain the
251 Makefile.vac makefile and os2build.cmd which is used to completely create the
252 binary distribution. The sequence of events for building the executable for
253 yourself goes something like this:
260 nmake -f Makefile.vac
263 You will see this sequence laid out in os2build.cmd.
265 -------------------------------------------------------------------------------
269 Click-click. (I need help on this. Not a clue here. Also for configuration
272 -------------------------------------------------------------------------------
276 Some quick notes on other Operating Systems.
278 For FreeBSD (and other *BSDs?), the build will require gmake instead of the
279 included make. gmake is available from http://www.gnu.org. The rest should be
280 the same as above for Linux/Unix.
282 -------------------------------------------------------------------------------
284 3. Invoking and Configuring JunkBuster
286 For Unix, *BSD and Linux, all configuration files are located in /etc/
287 junkbuster/ by default. For MS Windows, OS/2, and AmigaOS these are all in the
288 same directory as the Junkbuster executable. The name and number of
289 configuration files has changed from previous versions, and is subject to
290 change as development progresses.
292 The installed defaults provide a reasonable starting point, though possibly
293 aggressive by some standards. For the time being, there are only three default
294 configuration files (this will change in time):
296 * The main configuration file is named config on Linux, Unix, BSD, OS/2, and
297 AmigaOS and config.txt on Windows.
299 * The ijb.action file is used to define various "actions" relating to images,
300 banners, pop-ups, access restrictions, banners and cookies. There is a CGI
301 based editor for this file that can be accessed via http://i.j.b. This is
302 the easiest method of configuring actions. (Other actions files are
303 included as well with differing levels of filtering and blocking, e.g.
306 * The re_filterfile file can be used to rewrite the raw page content,
307 including text as well as embedded HTML and JavaScript.
309 ijb.action and re_filterfile can use Perl style regular expressions for maximum
310 flexibility. All files use the "#" character to denote a comment. Such lines
311 are not processed by Junkbuster. After making any changes, there is no need to
312 restart Junkbuster in order for the changes to take effect. Junkbuster should
313 detect such changes automatically.
315 While under development, the configuration content is subject to change. The
316 below documentation may not be accurate by the time you read this. Also, what
317 constitutes a "default" setting, may change, so please check all your
318 configuration files on important issues.
320 -------------------------------------------------------------------------------
322 3.1. Command Line Options
324 JunkBuster may be invoked with the following command-line options:
328 Print version info and exit, Unix only.
332 Print a short usage info and exit, Unix only.
336 Don't become a daemon, i.e. don't fork and become process group leader,
337 don't detach from controlling tty. Unix only.
341 On startup, write the process ID to FILE. Delete the FILE on exit. Failiure
342 to create or delete the FILE is non-fatal. If no FILE option is given, no
343 PID file will be used. Unix only.
347 If no configfile is included on the command line, JunkBuster will look for
348 a file named "config" in the current directory (except on Win32 where it
349 will look for "config.txt" instead). Specify full path to avoid confusion.
351 -------------------------------------------------------------------------------
353 3.2. The Main Configuration File
355 Again, the main configuration file is named config on Linux/Unix/BSD and OS/2,
356 and config.txt on Windows. Configuration lines consist of an initial keyword
357 followed by a list of values, all separated by whitespace (any number of spaces
358 or tabs). For example:
360 blockfile blocklist.ini
363 Indicates that the blockfile is named "blocklist.ini".
365 A "#" indicates a comment. Any part of a line following a "#" is ignored,
366 except if the "#" is preceded by a "\".
368 Thus, by placing a "#" at the start of an existing configuration line, you can
369 make it a comment and it will be treated as if it weren't there. This is called
370 "commenting out" an option and can be useful to turn off features: If you
371 comment out the "logfile" line, junkbuster will not log to a file at all. Watch
372 for the "default:" section in each explanation to see what happens if the
373 option is left unset (or commented out).
375 Long lines can be continued on the next line by using a "\" as the very last
378 There are various aspects of Junkbuster behavior that can be tuned.
380 -------------------------------------------------------------------------------
382 3.2.1. Defining Other Configuration Files
384 Junkbuster can use a number of other files to tell it what ads to block, what
385 cookies to accept, etc. This section of the configuration file tells Junkbuster
386 where to find all those other files.
388 On Windows and AmigaOS, Junkbuster looks for these files in the same directory
389 as the executable. On Unix and OS/2, Junkbuster looks for these files in the
390 current working directory. In either case, an absolute path name can be used to
393 When development goes modular and multi-user, the blocker, filter, and per-user
394 config will be stored in subdirectories of "confdir". For now, only confdir/
395 templates is used for storing HTML templates for CGI results.
397 The location of the configuration files:
399 confdir /etc/junkbuster # No trailing /, please.
402 The directory where all logging (i.e. logfile and jarfile) takes place. No
403 trailing "/", please:
405 logdir /var/log/junkbuster
408 Note that all file specifications below are relative to the above two
411 The "ijb.action" file contains patterns to specify the actions to apply to
412 requests for each site. Default: Cookies to and from all destinations are kept
413 only during the current browser session (i.e. they are not saved to disk).
414 Pop-ups are disabled for all sites. All sites are filtered if "re_filterfile"
415 specified. No sites are blocked. An empty image is displayed for filtered ads
416 and other images (formerly "tinygif"). The syntax of this file is explained in
419 actionsfile ijb.action
422 The "re_filterfile" file contains content modification rules. These rules
423 permit powerful changes on the content of Web pages, e.g., you could disable
424 your favorite JavaScript annoyances, rewrite the actual content, or just have
425 some fun replacing "Microsoft" with "MicroSuck" wherever it appears on a Web
426 page. Default: No content modification, or whatever the developers are playing
429 re_filterfile re_filterfile
432 The logfile is where all logging and error messages are written. The logfile
433 can be useful for tracking down a problem with Junkbuster (e.g., it's not
434 blocking an ad you think it should block) but in most cases you probably will
437 Your logfile will grow indefinitely, and you will probably want to periodically
438 remove it. On Unix systems, you can do this with a cron job (see "man cron").
439 For Redhat, a logrotate script has been included.
441 On SuSE Linux systems, you can place a line like "/var/log/junkbuster.* +1024k
442 644 nobody.nogroup" in /etc/logfiles, with the effect that cron.daily will
443 automatically archive, gzip, and empty the log, when it exceeds 1M size.
445 Default: Log to the a file named logfile. Comment out to disable logging.
450 The "jarfile" defines where Junkbuster stores the cookies it intercepts. Note
451 that if you use a "jarfile", it may grow quite large. Default: Don't store
457 If you specify a "trustfile", Junkbuster will only allow access to sites that
458 are named in the trustfile. You can also mark sites as trusted referrers, with
459 the effect that access to untrusted sites will be granted, if a link from a
460 trusted referrer was used. The link target will then be added to the
461 "trustfile". This is a very restrictive feature that typical users most
462 probably want to leave disabled. Default: Disabled, don't use the trust
468 If you use the trust mechanism, it is a good idea to write up some on-line
469 documentation about your blocking policy and to specify the URL(s) here. They
470 will appear on the page that your users receive when they try to access
471 untrusted content. Use multiple times for multiple URLs. Default: Don't display
472 links on the "untrusted" info page.
474 trust-info-url http://www.your-site.com/why_we_block.html
475 trust-info-url http://www.your-site.com/what_we_allow.html
478 -------------------------------------------------------------------------------
480 3.2.2. Other Configuration Options
482 This part of the configuration file contains options that control how
485 "Admin-address" should be set to the email address of the proxy administrator.
486 It is used in many of the proxy-generated pages. Default: fill@me.in.please.
488 #admin-address fill@me.in.please
491 "Proxy-info-url" can be set to a URL that contains more info about this
492 Junkbuster installation, it's configuration and policies. It is used in many of
493 the proxy-generated pages and its use is highly recommended in multi-user
494 installations, since your users will want to know why certain content is
495 blocked or modified. Default: Don't show a link to on-line documentation.
497 proxy-info-url http://www.your-site.com/proxy.html
500 "Listen-address" specifies the address and port where Junkbuster will listen
501 for connections from your Web browser. The default is to listen on the
502 localhost port 8118, and this is suitable for most users. (In your web browser,
503 under proxy configuration, list the proxy server as "localhost" and the port as
506 If you already have another service running on port 8118, or if you want to
507 serve requests from other machines (e.g. on your local network) as well, you
508 will need to override the default. The syntax is "listen-address
509 [<ip-address>]:<port>". If you leave out the IP address, junkbuster will bind
510 to all interfaces (addresses) on your machine and may become reachable from the
511 Internet. In that case, consider using access control lists (acl's) (see
512 "aclfile" above), or a firewall.
514 For example, suppose you are running Junkbuster on a machine which has the
515 address 192.168.0.1 on your local private network (192.168.0.0) and has another
516 outside connection with a different address. You want it to serve requests from
519 listen-address 192.168.0.1:8118
522 If you want it to listen on all addresses (including the outside connection):
527 If you do this, consider using ACLs (see "aclfile" above). Note: you will need
528 to point your browser(s) to the address and port that you have configured here.
529 Default: localhost:8118 (127.0.0.1:8118).
531 The debug option sets the level of debugging information to log in the logfile
532 (and to the console in the Windows version). A debug level of 1 is informative
533 because it will show you each request as it happens. Higher levels of debug are
534 probably only of interest to developers.
536 debug 1 # GPC = show each GET/POST/CONNECT request
537 debug 2 # CONN = show each connection status
538 debug 4 # IO = show I/O status
539 debug 8 # HDR = show header parsing
540 debug 16 # LOG = log all data into the logfile
541 debug 32 # FRC = debug force feature
542 debug 64 # REF = debug regular expression filter
543 debug 128 # = debug fast redirects
544 debug 256 # = debug GIF de-animation
545 debug 512 # CLF = Common Log Format
546 debug 1024 # = debug kill pop-ups
547 debug 4096 # INFO = Startup banner and warnings.
548 debug 8192 # ERROR = Non-fatal errors
551 It is highly recommended that you enable ERROR reporting (debug 8192), at least
552 until the next stable release.
554 The reporting of FATAL errors (i.e. ones which crash JunkBuster) is always on
555 and cannot be disabled.
557 If you want to use CLF (Common Log Format), you should set "debug 512" ONLY, do
558 not enable anything else.
560 Multiple "debug" directives, are OK - they're logical-OR'd together.
562 debug 15 # same as setting the first 4 listed above
569 debug 8192 # Errors - *we highly recommended enabling this*
572 Junkbuster normally uses "multi-threading", a software technique that permits
573 it to handle many different requests simultaneously. In some cases you may wish
574 to disable this -- particularly if you're trying to debug a problem. The
575 "single-threaded" option forces Junkbuster to handle requests sequentially.
576 Default: Multi-threaded mode.
581 "toggle" allows you to temporarily disable all Junkbuster's filtering. Just set
584 The Windows version of Junkbuster puts an icon in the system tray, which also
585 allows you to change this option. If you right-click on that icon (or select
586 the "Options" menu), one choice is "Enable". Clicking on enable toggles
587 Junkbuster on and off. This is useful if you want to temporarily disable
588 Junkbuster, e.g., to access a site that requires cookies which you would
589 otherwise have blocked. This can also be toggled via a web browser at the
590 Junkbuster internal address of http://i.j.b on any platform.
592 "toggle 1" means Junkbuster runs normally, "toggle 0" means that Junkbuster
593 becomes a non-anonymizing non-blocking proxy. Default: 1 (on).
598 For content filtering, i.e. the "+filter" and "+deanimate-gif" actions, it is
599 necessary that Junkbuster buffers the entire document body. This can be
600 potentially dangerous, since a server could just keep sending data indefinitely
601 and wait for your RAM to exhaust. With nasty consequences.
603 The buffer-limit option lets you set the maximum size in Kbytes that each
604 buffer may use. When the documents buffer exceeds this size, it is flushed to
605 the client unfiltered and no further attempt to filter the rest of it is made.
606 Remember that there may multiple threads running, which might require
607 increasing the "buffer-limit" Kbytes each, unless you have enabled
608 "single-threaded" above.
613 To enable the web-based ijb.action file editor set enable-edit-actions to 1, or
614 0 to disable. Note that you must have compiled JunkBuster with support for this
615 feature, otherwise this option has no effect. This internal page can be reached
618 Security note: If this is enabled, anyone who can use the proxy can edit the
619 actions file, and their changes will affect all users. For shared proxies, you
620 probably want to disable this. Default: enabled.
622 enable-edit-actions 1
625 Allow JunkBuster to be toggled on and off remotely, using your web browser. Set
626 "enable-remote-toggle"to 1 to enable, and 0 to disable. Note that you must have
627 compiled JunkBuster with support for this feature, otherwise this option has no
630 Security note: If this is enabled, anyone who can use the proxy can toggle it
631 on or off (see http://i.j.b), and their changes will affect all users. For
632 shared proxies, you probably want to disable this. Default: enabled.
634 enable-remote-toggle 1
637 -------------------------------------------------------------------------------
639 3.2.3. Access Control List (ACL)
641 Access controls are included at the request of some ISPs and systems
642 administrators, and are not usually needed by individual users. Please note the
643 warnings in the FAQ that this proxy is not intended to be a substitute for a
644 firewall or to encourage anyone to defer addressing basic security weaknesses.
646 If no access settings are specified, the proxy talks to anyone that connects.
647 If any access settings file are specified, then the proxy talks only to IP
648 addresses permitted somewhere in this file and not denied later in this file.
650 Summary -- if using an ACL:
652 Client must have permission to receive service.
654 LAST match in ACL wins.
656 Default behavior is to deny service.
658 The syntax for an entry in the Access Control List is:
660 ACTION SRC_ADDR[/SRC_MASKLEN] [ DST_ADDR[/DST_MASKLEN] ]
663 Where the individual fields are:
665 ACTION = "permit-access" or "deny-access"
667 SRC_ADDR = client hostname or dotted IP address
668 SRC_MASKLEN = number of bits in the subnet mask for the source
670 DST_ADDR = server or forwarder hostname or dotted IP address
671 DST_MASKLEN = number of bits in the subnet mask for the target
674 The field separator (FS) is whitespace (space or tab).
676 IMPORTANT NOTE: If the junkbuster is using a forwarder (see below) or a gateway
677 for a particular destination URL, the DST_ADDR that is examined is the address
678 of the forwarder or the gateway and NOT the address of the ultimate target.
679 This is necessary because it may be impossible for the local Junkbuster to
680 determine the address of the ultimate target (that's often what gateways are
683 Here are a few examples to show how the ACL features work:
685 "localhost" is OK -- no DST_ADDR implies that ALL destination addresses are OK:
687 permit-access localhost
690 A silly example to illustrate permitting any host on the class-C subnet with
691 Junkbuster to go anywhere:
693 permit-access www.junkbusters.com/24
696 Except deny one particular IP address from using it at all:
698 deny-access ident.junkbusters.com
701 You can also specify an explicit network address and subnet mask. Explicit
702 addresses do not have to be resolved to be used.
704 permit-access 207.153.200.0/24
707 A subnet mask of 0 matches anything, so the next line permits everyone.
709 permit-access 0.0.0.0/0
712 Note, you cannot say:
717 to allow all *.org domains. Every IP address listed must resolve fully.
719 An ISP may want to provide a Junkbuster that is accessible by "the world" and
720 yet restrict use of some of their private content to hosts on its internal
721 network (i.e. its own subscribers). Say, for instance the ISP owns the Class-B
722 IP address block 123.124.0.0 (a 16 bit netmask). This is how they could do it:
724 permit-access 0.0.0.0/0 0.0.0.0/0 # other clients can go anywhere
725 # with the following exceptions:
727 deny-access 0.0.0.0/0 123.124.0.0/16 # block all external requests for
728 # sites on the ISP's network
730 permit 0.0.0.0/0 www.my_isp.com # except for the ISP's main
733 permit 123.124.0.0/16 0.0.0.0/0 # the ISP's clients can go
737 Note that if some hostnames are listed with multiple IP addresses, the primary
738 value returned by DNS (via gethostbyname()) is used. Default: Anyone can access
741 -------------------------------------------------------------------------------
745 This feature allows chaining of HTTP requests via multiple proxies. It can be
746 used to better protect privacy and confidentiality when accessing specific
747 domains by routing requests to those domains to a special purpose filtering
748 proxy such as lpwa.com. Or to use a caching proxy to speed up browsing.
750 It can also be used in an environment with multiple networks to route requests
751 via multiple gateways allowing transparent access to multiple networks without
752 having to modify browser configurations.
754 Also specified here are SOCKS proxies. Junkbuster SOCKS 4 and SOCKS 4A. The
755 difference is that SOCKS 4A will resolve the target hostname using DNS on the
756 SOCKS server, not our local DNS client.
758 The syntax of each line is:
760 forward target_domain[:port] http_proxy_host[:port]
761 forward-socks4 target_domain[:port] socks_proxy_host[:port] http_proxy_host[:
763 forward-socks4a target_domain[:port] socks_proxy_host[:port] http_proxy_host[:
767 If http_proxy_host is ".", then requests are not forwarded to a HTTP proxy but
768 are made directly to the web servers.
770 Lines are checked in sequence, and the last match wins.
772 There is an implicit line equivalent to the following, which specifies that
773 anything not finding a match on the list is to go out without forwarding or
774 gateway protocol, like so:
776 forward .* . # implicit
779 In the following common configuration, everything goes to Lucent's LPWA, except
780 SSL on port 443 (which it doesn't handle):
782 forward .* lpwa.com:8000
786 See the FAQ for instructions on how to automate the login procedure for LPWA.
787 Some users have reported difficulties related to LPWA's use of "." as the last
788 element of the domain, and have said that this can be fixed with this:
790 forward lpwa. lpwa.com:8000
793 (NOTE: the syntax for specifying target_domain has changed since the previous
794 paragraph was written -- it will not work now. More information is welcome.)
796 In this fictitious example, everything goes via an ISP's caching proxy, except
797 requests to that ISP:
799 forward .* caching.myisp.net:8000
803 For the @home network, we're told the forwarding configuration is this:
805 forward .* proxy:8080
808 Also, we're told they insist on getting cookies and JavaScript, so you should
809 add home.com to the cookie file. We consider JavaScript a security risk. Java
812 In this example direct connections are made to all "internal" domains, but
813 everything else goes through Lucent's LPWA by way of the company's SOCKS
814 gateway to the Internet.
816 forward-socks4 .* lpwa.com:8000 firewall.my_company.com:1080
817 forward my_company.com .
820 This is how you could set up a site that always uses SOCKS but no forwarders:
822 forward-socks4a .* . firewall.my_company.com:1080
825 An advanced example for network administrators:
827 If you have links to multiple ISPs that provide various special content to
828 their subscribers, you can configure forwarding to pass requests to the
829 specific host that's connected to that ISP so that everybody can see all of the
830 content on all of the ISPs.
832 This is a bit tricky, but here's an example:
834 host-a has a PPP connection to isp-a.com. And host-b has a PPP connection to
835 isp-b.com. host-a can run a Junkbuster proxy with forwarding like this:
838 forward isp-b.com host-b:8118
841 host-b can run a Junkbuster proxy with forwarding like this:
844 forward isp-a.com host-a:8118
847 Now, anyone on the Internet (including users on host-a and host-b) can set
848 their browser's proxy to either host-a or host-b and be able to browse the
849 content on isp-a or isp-b.
851 Here's another practical example, for University of Kent at Canterbury students
852 with a network connection in their room, who need to use the University's Squid
855 forward *. ssbcache.ukc.ac.uk:3128 # Use the proxy, except for:
856 forward .ukc.ac.uk . # Anything on the same domain as us
857 forward * . # Host with no domain specified
858 forward 129.12.*.* . # A dotted IP on our /16 network.
859 forward 127.*.*.* . # Loopback address
860 forward localhost.localdomain . # Loopback address
861 forward www.ukc.mirror.ac.uk . # Specific host
864 If you intend to chain Junkbuster and squid locally, then chain as browser ->
865 squid -> junkbuster is the recommended way.
867 Your squid configuration could then look like this:
869 # Define junkbuster as parent cache
871 cache_peer 127.0.0.1 parent 8118 0 no-query
873 # Define ACL for protocol FTP
876 # Do not forward ACL FTP to junkbuster
877 always_direct allow FTP
879 # Do not forward ACL CONNECT (https) to junkbuster
880 always_direct allow CONNECT
882 # Forward the rest to junkbuster
883 never_direct allow all
886 -------------------------------------------------------------------------------
888 3.2.5. Windows GUI Options
890 Junkbuster has a number of options specific to the Windows GUI interface:
892 If "activity-animation" is set to 1, the Junkbuster icon will animate when
893 "Junkbuster" is active. To turn off, set to 0.
898 If "log-messages" is set to 1, Junkbuster will log messages to the console
904 If "log-buffer-size" is set to 1, the size of the log buffer, i.e. the amount
905 of memory used for the log messages displayed in the console window, will be
906 limited to "log-max-lines" (see below).
908 Warning: Setting this to 0 will result in the buffer to grow infinitely and eat
914 log-max-lines is the maximum number of lines held in the log buffer. See above.
919 If "log-highlight-messages" is set to 1, Junkbuster will highlight portions of
920 the log messages with a bold-faced font:
922 log-highlight-messages 1
925 The font used in the console window:
927 log-font-name Comic Sans MS
930 Font size used in the console window:
935 "show-on-task-bar" controls whether or not Junkbuster will appear as a button
936 on the Task bar when minimized:
941 If "close-button-minimizes" is set to 1, the Windows close button will minimize
942 Junkbuster instead of closing the program (close with the exit option on the
945 close-button-minimizes 1
948 The "hide-console" option is specific to the MS-Win console version of
949 JunkBuster. If this option is used, Junkbuster will disconnect from and hide
955 -------------------------------------------------------------------------------
957 3.3. The Actions File
959 The "ijb.action" file (formerly actionsfile) is used to define what actions
960 Junkbuster takes, and thus determines how images, cookies and various other
961 aspects of HTTP content and transactions are handled. Images can be anything
962 you want, including ads, banners, or just some obnoxious image that you would
963 rather not see. Cookies can be accepted or rejected, or accepted only during
964 the current browser session (i.e. not written to disk). Changes to ijb.action
965 should be immediately visible to Junkbuster without the need to restart.
967 To determine which actions apply to a request, the URL of the request is
968 compared to all patterns in this file. Every time it matches, the list of
969 applicable actions for the URL is incrementally updated. You can trace this
970 process by visiting http://i.j.b/show-url-info.
972 The actions file can be edited with a browser by loading http://i.j.b/, and
973 then select "Edit Actions".
975 There are four types of lines in this file: comments (begin with a "#"
976 character), actions, aliases and patterns, all of which are explained below, as
977 well as the configuration file syntax that Junkbuster understands.
979 -------------------------------------------------------------------------------
981 3.3.1. URL Domain and Path Syntax
983 Generally, a pattern has the form <domain>/<path>, where both the <domain> and
984 <path> part are optional. If you only specify a domain part, the "/" can be
987 www.example.com - is a domain only pattern and will match any request to
990 www.example.com/ - means exactly the same.
992 www.example.com/index.html - matches only the single document "/index.html" on
995 /index.html - matches the document "/index.html", regardless of the domain.
997 index.html - matches nothing, since it would be interpreted as a domain name
998 and there is no top-level domain called ".html".
1000 The matching of the domain part offers some flexible options: if the domain
1001 starts or ends with a dot, it becomes unanchored at that end. For example:
1003 .example.com - matches any domain that ENDS in ".example.com".
1005 www. - matches any domain that STARTS with "www".
1007 Additionally, there are wild-cards that you can use in the domain names
1008 themselves. They work pretty similar to shell wild-cards: "*" stands for zero
1009 or more arbitrary characters, "?" stands for any single character. And you can
1010 define character classes in square brackets and they can be freely mixed:
1012 ad*.example.com - matches "adserver.example.com", "ads.example.com", etc but
1013 not "sfads.example.com".
1015 *ad*.example.com - matches all of the above, and then some.
1017 .?pix.com - matches "www.ipix.com", "pictures.epix.com", "a.b.c.d.e.upix.com",
1020 www[1-9a-ez].example.com - matches "www1.example.com", "www4.example.com",
1021 "wwwd.example.com", "wwwz.example.com", etc., but not "wwww.example.com".
1023 If Junkbuster was compiled with "pcre" support (default), Perl compatible
1024 regular expressions can be used. See the pcre/docs/ directory or "man perlre"
1025 (also available on http://www.perldoc.com/perl5.6/pod/perlre.html) for details.
1026 A brief discussion of regular expressions is in the Appendix. For instance:
1028 /.*/advert[0-9]+\.jpe?g - would match a URL from any domain, with any path that
1029 includes "advert" followed immediately by one or more digits, then a "." and
1030 ending in either "jpeg" or "jpg". So we match "example.com/ads/advert2.jpg",
1031 and "www.example.com/ads/banners/advert39.jpeg", but not "www.example.com/ads/
1032 banners/advert39.gif" (no gifs in the example pattern).
1034 Please note that matching in the path is case INSENSITIVE by default, but you
1035 can switch to case sensitive at any point in the pattern by using the "(?-i)"
1038 www.example.com/(?-i)PaTtErN.* - will match only documents whose path starts
1039 with "PaTtErN" in exactly this capitalization.
1041 -------------------------------------------------------------------------------
1045 Actions are enabled if preceded with a "+", and disabled if preceded with a
1046 "-". Actions are invoked by enclosing the action name in curly braces (e.g.
1047 {+some_action}), followed by a list of URLs to which the action applies. There
1048 are three classes of actions:
1050 * Boolean (e.g. "+/-block"):
1052 {+name} # enable this action
1053 {-name} # disable this action
1056 * parameterized (e.g. "+/-hide-user-agent"):
1058 {+name{param}} # enable action and set parameter to "param"
1059 {-name} # disable action
1062 * Multi-value (e.g. "{+/-add-header{Name: value}}", "{+/-wafer{name=value}}
1065 {+name{param}} # enable action and add parameter "param"
1066 {-name{param}} # remove the parameter "param"
1067 {-name} # disable this action totally
1070 If nothing is specified in this file, no "actions" are taken. So in this case
1071 JunkBuster would just be a normal, non-blocking, non-anonymizing proxy. You
1072 must specifically enable the privacy and blocking features you need (although
1073 the provided default ijb.action file will give a good starting point).
1075 Later defined actions always over-ride earlier ones. For multi-valued actions,
1076 the actions are applied in the order they are specified.
1078 The list of valid Junkbuster "actions" are:
1080 * Add the specified HTTP header, which is not checked for validity. You may
1081 specify this many times to specify many different headers:
1083 +add-header{Name: value}
1086 * Block this URL totally.
1091 * De-animate all animated GIF images, i.e. reduce them to their last frame.
1092 This will also shrink the images considerably (in bytes, not pixels!). If
1093 the option "first" is given, the first frame of the animation is used as
1094 the replacement. If "last" is given, the last frame of the animation is
1095 used instead, which probably makes more sense for most banner animations,
1096 but also has the risk of not showing the entire last frame (if it is only a
1097 delta to an earlier frame).
1099 +deanimate-gifs{last}
1100 +deanimate-gifs{first}
1103 * "+downgrade" will downgrade HTTP/1.1 client requests to HTTP/1.0 and
1104 downgrade the responses as well. Use this action for servers that use HTTP/
1105 1.1 protocol features that Junkbuster doesn't handle well yet. HTTP/1.1 is
1106 only partially implemented. Default is not to downgrade requests.
1111 * Many sites, like yahoo.com, don't just link to other sites. Instead, they
1112 will link to some script on their own server, giving the destination as a
1113 parameter, which will then redirect you to the final target. URLs resulting
1114 from this scheme typically look like: http://some.place/some_script?http://
1117 Sometimes, there are even multiple consecutive redirects encoded in the
1118 URL. These redirections via scripts make your web browsing more traceable,
1119 since the server from which you follow such a link can see where you go to.
1120 Apart from that, valuable bandwidth and time is wasted, while your browser
1121 ask the server for one redirect after the other. Plus, it feeds the
1124 The "+fast-redirects" option enables interception of these requests by
1125 Junkbuster, who will cut off all but the last valid URL in the request and
1126 send a local redirect back to your browser without contacting the remote
1132 * Filter the website through the re_filterfile:
1137 * Block any existing X-Forwarded-for header, and do not add a new one:
1142 * If the browser sends a "From:" header containing your e-mail address, this
1143 either completely removes the header ("block"), or changes it to the
1144 specified e-mail address.
1147 +hide-from{spam@sittingduck.xqq}
1150 * Don't send the "Referer:" (sic) header to the web site. You can block it,
1151 forge a URL to the same server as the request (which is preferred because
1152 some sites will not send images otherwise) or set it to a constant string
1155 +hide-referer{block}
1156 +hide-referer{forge}
1157 +hide-referer{http://nowhere.com}
1160 * Alternative spelling of "+hide-referer". It has the same parameters, and
1161 can be freely mixed with, "+hide-referer". ("referrer" is the correct
1162 English spelling, however the HTTP specification has a bug - it requires it
1163 to be spelled "referer".)
1168 * Change the "User-Agent:" header so web servers can't tell your browser
1169 type. Warning! This breaks many web sites. Specify the user-agent value you
1170 want. Example, pretend to be using Netscape on Linux:
1172 +hide-user-agent{Mozilla (X11; I; Linux 2.0.32 i586)}
1175 * Treat this URL as an image. This only matters if it's also "+block"ed, in
1176 which case a "blocked" image can be sent rather than a HTML page. See
1177 "+image-blocker{}" below for the control over what is actually sent.
1182 * Decides what to do with URLs that end up tagged with "{+block +image}".
1183 There are 4 options. "-image-blocker" will send a HTML "blocked" page,
1184 usually resulting in a "broken image" icon. "+image-blocker{logo}" will
1185 send a "JunkBuster" image. "+image-blocker{blank}" will send a 1x1
1186 transparent GIF image. And finally, "+image-blocker{http://xyz.com}" will
1187 send a HTTP temporary redirect to the specified image. This has the
1188 advantage of the icon being being cached by the browser, which will speed
1191 +image-blocker{logo}
1192 +image-blocker{blank}
1193 +image-blocker{http://i.j.b/send-banner}
1196 * By default (i.e. in the absence of a "+limit-connect" action), Junkbuster
1197 will only allow CONNECT requests to port 443, which is the standard port
1198 for https as a precaution.
1200 The CONNECT methods exists in HTTP to allow access to secure websites
1201 (https:// URLs) through proxies. It works very simply: the proxy connects
1202 to the server on the specified port, and then short-circuits its
1203 connections to the client and to the remote proxy. This can be a big
1204 security hole, since CONNECT-enabled proxies can be abused as TCP relays
1207 If you want to allow CONNECT for more ports than this, or want to forbid
1208 CONNECT altogether, you can specify a comma separated list of ports and
1209 port ranges (the latter using dashes, with the minimum defaulting to 0 and
1212 +limit-connect{443} # This is the default and need no be specified.
1213 +limit-connect{80,443} # Ports 80 and 443 are OK.
1214 +limit-connect{-3, 7, 20-100, 500-} # Port less than 3, 7, 20 to 100
1215 #and above 500 are OK.
1218 * "+no-compression" prevents the website from compressing the data. Some
1219 websites do this, which can be a problem for Junkbuster, since "+filter",
1220 "+no-popup" and "+gif-deanimate" will not work on compressed data. This
1221 will slow down connections to those websites, though. Default is
1222 "nocompression" is turned on.
1227 * If the website sets cookies, "no-cookies-keep" will make sure they are
1228 erased when you exit and restart your web browser. This makes profiling
1229 cookies useless, but won't break sites which require cookies so that you
1230 can log in for transactions. Default: on.
1235 * Prevent the website from reading cookies:
1240 * Prevent the website from setting cookies:
1245 * Filter the website through a built-in filter to disable those obnoxious
1246 JavaScript pop-up windows via window.open(), etc. The two alternative
1247 spellings are equivalent.
1253 * This action only applies if you are using a jarfile for saving cookies. It
1254 sends a cookie to every site stating that you do not accept any copyright
1255 on cookies sent to you, and asking them not to track you. Of course, this
1256 is a (relatively) unique header they could use to track you.
1261 * This allows you to add an arbitrary cookie. It can be specified multiple
1262 times in order to add as many cookies as you like.
1267 The meaning of any of the above is reversed by preceding the action with a "-",
1268 in place of the "+".
1272 Turn off cookies by default, then allow a few through for specified sites:
1274 # Turn off all persistent cookies
1275 { +no-cookies-read }
1277 # Allow cookies for this browser session ONLY
1278 { +no-cookies-keep }
1280 # Exceptions to the above, sites that benefit from persistent cookies
1281 { -no-cookies-read }
1283 { -no-cookies-keep }
1290 # Alternative way of saying the same thing
1291 {-no-cookies-set -no-cookies-read -no-cookies-keep}
1296 Now turn off "fast redirects", and then we allow two exceptions:
1301 # Reverse it for these two sites, which don't work right without it.
1303 www.ukc.ac.uk/cgi-bin/wac\.cgi\?
1307 Turn on page filtering, with one exception for sourceforge:
1309 # Run everything through the default filter file (re_filterfile):
1312 # But please don't re_filter code from sourceforge!
1314 .cvs.sourceforge.net
1317 Now some URLs that we want "blocked", ie we won't see them. Many of these use
1318 regular expressions that will expand to match multiple URLs:
1322 /.*/(.*[-_.])?ads?[0-9]?(/|[-_.].*|\.(gif|jpe?g))
1323 /.*/(.*[-_.])?count(er)?(\.cgi|\.dll|\.exe|[?/])
1324 /.*/(ng)?adclient\.cgi
1325 /.*/(plain|live|rotate)[-_.]?ads?/
1326 /.*/(sponsor)s?[0-9]?/
1327 /.*/_?(plain|live)?ads?(-banners)?/
1329 /.*/ad(sdna_image|gifs?)/
1330 /.*/ad(server|stream|juggler)\.(cgi|pl|dll|exe)
1334 /.*/adv((er)?ts?|ertis(ing|ements?))?/
1338 /.*/cgi-bin/centralad/getimage
1339 /.*/images/addver\.gif
1340 /.*/images/marketing/.*\.(gif|jpe?g)
1344 /.*/sponsors?[0-9]?/
1345 /.*/advert[0-9]+\.jpg
1352 /graphics/defaultAd/
1354 /image\.ng/transactionID
1355 /images/.*/.*_anim\.gif # alvin brattli
1356 /ip_img/.*\.(gif|jpe?g)
1360 /cgi-bin/nph-adclick.exe/
1361 /.*/Image/BannerAdvertising/
1363 /.*/adlib/server\.cgi
1367 -------------------------------------------------------------------------------
1371 Custom "actions", known to Junkbuster as "aliases", can be defined by combining
1372 other "actions". These can in turn be invoked just like the built-in "actions".
1373 Currently, an alias can contain any character except space, tab, "=", "{" or "}
1374 ". But please use only "a"- "z", "0"-"9", "+", and "-". Alias names are not
1375 case sensitive, and must be defined before anything else in the ijb.actionfile
1376 ! And there can only be one set of "aliases" defined.
1378 Now let's define a few aliases:
1380 # Useful customer aliases we can use later. These must come first!
1382 +no-cookies = +no-cookies-set +no-cookies-read
1383 -no-cookies = -no-cookies-set -no-cookies-read
1385 -block -no-cookies -filter -fast-redirects -hide-referer -no-popups
1386 shop = -no-cookies -filter -fast-redirects
1387 +imageblock = +block +image
1389 #For people who don't like to type too much: ;-)
1392 c2 = -no-cookies-set +no-cookies-read
1393 c3 = +no-cookies-set -no-cookies-read
1394 #... etc. Customize to your heart's content.
1397 Some examples using our "shop" and "fragile" aliases from above:
1399 # These sites are very complex and require
1400 # minimal interference.
1402 .office.microsoft.com
1403 .windowsupdate.microsoft.com
1406 # Shopping sites - still want to block ads.
1409 .worldpay.com # for quietpc.com
1413 # These shops require pop-ups
1419 -------------------------------------------------------------------------------
1421 3.4. The Filter File
1423 The filter file defines what filtering of web pages Junkbuster does. The
1424 default filter file is re_filterfile, located in the config directory. In this
1425 file, any document content, whether viewable text or embedded non-visible
1426 content, can be changed.
1428 This file uses regular expressions to alter or remove any string in the target
1429 page. Some examples from the included default re_filterfile:
1431 Stop web pages from displaying annoying messages in the status bar by deleting
1434 # The status bar is for displaying link targets, not pointless buzzwords.
1435 # Again, check it out on http://www.airport-cgn.de/.
1436 s/status='.*?';*//ig
1439 Just for kicks, replace any occurrence of "Microsoft" with "MicroSuck":
1441 s/microsoft(?!.com)/MicroSuck/ig
1444 Kill those auto-refresh tags:
1446 # Kill refresh tags. I like to refresh myself. Manually.
1447 # check it out on http://www.airport-cgn.de/ and go to the arrivals page.
1449 s/<meta[^>]*http-equiv[^>]*refresh.*URL=([^>]*?)"?>/<link rev="x-refresh" href
1451 s/<meta[^>]*http-equiv="?page-enter"?[^>]*content=[^>]*>/<!
1452 --no page enter for me-->/i
1455 -------------------------------------------------------------------------------
1459 When Junkbuster displays one of its internal pages, such as a 404 Not Found
1460 error page, it uses the appropriate template. On Linux, BSD, and Unix, these
1461 are locate in /etc/junkbuster/templates by default. These may be customized, if
1464 -------------------------------------------------------------------------------
1466 4. Quickstart to Using Junkbuster
1468 Install package, then run and enjoy! JunkBuster accepts only one command line
1469 option -- the configuration file to be used. Example Unix startup command:
1472 # /usr/sbin/junkbuster /etc/junkbuster/config
1476 An init script is provided for SuSE and Redhat.
1478 For for SuSE: /etc/rc.d/junkbuster start
1480 For RedHat: /etc/rc.d/init.d/junkbuster start
1482 If no configuration file is specified on the command line, Junkbuster will look
1483 for a file named config in the current directory. Except on Win32 where it will
1484 try config.txt. If no file is specified on the command line and no default
1485 configuration file can be found, Junkbuster will fail to start.
1487 Be sure your browser is set to use the proxy which is by default at localhost,
1488 port 8118. With Netscape (and Mozilla), this can be set under Edit ->
1489 Preferences -> Advanced -> Proxies -> HTTP Proxy. For Internet Explorer: Tools
1490 > Internet Properties -> Connections -> LAN Setting. Then, check "Use Proxy"
1491 and fill in the appropriate info (Address: localhost, Port: 8118). Include if
1492 HTTPS proxy support too.
1494 The included default configuration files should give a reasonable starting
1495 point, though may be somewhat aggressive in blocking junk. You will probably
1496 want to keep an eye out for sites that require persistent cookies, and add
1497 these to ijb.action as needed. By default, most of these will be accepted only
1498 during the current browser session, until you add them to the configuration. If
1499 you want the browser to handle this instead, you will need to edit ijb.action
1500 and disable this feature. If you use more than one browser, it would make more
1501 sense to let Junkbuster handle this. In which case, the browser(s) should be
1502 set to accept all cookies.
1504 If a particular site shows problems loading properly, try adding it to the
1505 {fragile} section of ijb.action. This will turn off most actions for this site.
1507 Junkbuster is HTTP/1.1 compliant, but not all 1.1 features are as yet
1508 implemented. If browsers that support HTTP/1.1 (like Mozilla or recent versions
1509 of I.E.) experience problems, you might try to force HTTP/1.0 compatibility.
1510 For Mozilla, look under Edit -> Preferences -> Debug -> Networking. Or set the
1511 "+downgrade" config option in ijb.action.
1513 After running Junkbuster for a while, you can start to fine tune the
1514 configuration to suit your personal, or site, preferences and requirements.
1515 There are many, many aspects that can be customized. "Actions" (as specified in
1516 ijb.action) can be adjusted by pointing your browser to http://i.j.b/, and then
1517 follow the link to "edit the actions list". (This is an internal page and does
1518 not require Internet access.)
1520 In fact, various aspects of Junkbuster configuration can be viewed from this
1521 page, including current configuration parameters, source code version numbers,
1522 the browser's request headers, and "actions" that apply to a given URL. In
1523 addition to the ijb.action file editor mentioned above, Junkbuster can also be
1524 turned "on" and "off" from this page.
1526 If you encounter problems, please verify it is a Junkbuster bug, by disabling
1527 Junkbuster, and then trying the same page. Also, try another browser if
1528 possible to eliminate browser or site problems. Before reporting it as a bug,
1529 see if there is not a configuration option that is enabled that is causing the
1530 page not to load. You can then add an exception for that page or site. If a
1531 bug, please report it to the developers (see below).
1533 -------------------------------------------------------------------------------
1535 5. Contacting the Developers, Bug Reporting and Feature Requests
1537 Please do not use the mailing lists for feature requests or bug reports. They
1538 are not as easily tracked this way!
1540 Feature requests and other questions should be posted to the Feature request
1541 page at SourceForge. There is also an archive there.
1543 Anyone interested in actively participating in development and related
1544 discussions can join the appropriate mailing list here. Archives are available
1547 Please report bugs, using the form at Sourceforge. Please try to verify that it
1548 is a Junkbuster bug, and not a browser or site bug first. Also, check to make
1549 sure this is not already a known bug. If you are using your own custom
1550 configuration, please try the stock configs to see if the problem is a
1551 configuration related bug.
1553 -------------------------------------------------------------------------------
1555 6. Copyright and History
1559 Internet Junkbuster is free software; you can redistribute it and/or modify it
1560 under the terms of the GNU General Public License as published by the Free
1561 Software Foundation; either version 2 of the License, or (at your option) any
1564 This program is distributed in the hope that it will be useful, but WITHOUT ANY
1565 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
1566 PARTICULAR PURPOSE. See the GNU General Public License for more details, which
1567 is available from the Free Software Foundation, Inc, 59 Temple Place - Suite
1568 330, Boston, MA 02111-1307, USA.
1570 -------------------------------------------------------------------------------
1574 Junkbuster was originally written by Anonymous Coders and Junkbuster's
1575 Corporation, and was released as free open-source software under the GNU GPL.
1576 Stefan Waldherr made many improvements, and started the SourceForge project to
1577 rekindle development. There are now several active developers contributing. The
1578 last stable release was v2.0.2, which has now grown whiskers ;-).
1580 -------------------------------------------------------------------------------
1584 http://sourceforge.net/projects/ijbswa
1586 http://ijbswa.sourceforge.net/
1590 http://www.junkbusters.com/ht/en/cookies.html
1592 http://www.waldherr.org/junkbuster/
1594 http://privacy.net/analyze/
1596 http://www.squid-cache.org/
1600 -------------------------------------------------------------------------------
1604 8.1. Regular Expressions
1606 Junkbuster can use "regular expressions" in various config files. Assuming
1607 support for "pcre" (Perl Compatible Regular Expressions) is compiled in, which
1608 is the default. Such configuration directives do not require regular
1609 expressions, but they can be used to increase flexibility by matching a pattern
1610 with wild-cards against URLs.
1612 If you are reading this, you probably don't understand what "regular
1613 expressions" are, or what they can do. So this will be a very brief
1614 introduction only. A full explanation would require a book ;-)
1616 "Regular expressions" is a way of matching one character expression against
1617 another to see if it matches or not. One of the "expressions" is a literal
1618 string of readable characters (letter, numbers, etc), and the other is a
1619 complex string of literal characters combined with wild-cards, and other
1620 special characters, called meta-characters. The "meta-characters" have special
1621 meanings and are used to build the complex pattern to be matched against. Perl
1622 Compatible Regular Expressions is an enhanced form of the regular expression
1623 language with backward compatibility.
1625 To make a simple analogy, we do something similar when we use wild-card
1626 characters when listing files with the dir command in DOS. *.* matches all
1627 filenames. The "special" character here is the asterisk which matches any and
1628 all characters. We can be more specific and use ? to match just individual
1629 characters. So "dir file?.text" would match "file1.txt", "file2.txt", etc. We
1630 are pattern matching, using a similar technique to "regular expressions"!
1632 Regular expressions do essentially the same thing, but are much, much more
1633 powerful. There are many more "special characters" and ways of building complex
1634 patterns however. Let's look at a few of the common ones, and then some
1637 . - Matches any single character, e.g. "a", "A", "4", ":", or "@".
1639 ? - The preceding character or expression is matched ZERO or ONE times. Either/
1642 + - The preceding character or expression is matched ONE or MORE times.
1644 * - The preceding character or expression is matched ZERO or MORE times.
1646 \ - The "escape" character denotes that the following character should be taken
1647 literally. This is used where one of the special characters (e.g. ".") needs to
1648 be taken literally and not as a special meta-character.
1650 [] - Characters enclosed in brackets will be matched if any of the enclosed
1651 characters are encountered.
1653 () - parentheses are used to group a sub-expression, or multiple
1656 | - The "bar" character works like an "or" conditional statement. A match is
1657 successful if the sub-expression on either side of "|" matches.
1659 s/string1/string2/g - This is used to rewrite strings of text. "string1" is
1660 replaced by "string2" in this example.
1662 These are just some of the ones you are likely to use when matching URLs with
1663 Junkbuster, and is a long way from a definitive list. This is enough to get us
1664 started with a few simple examples which may be more illuminating:
1666 /.*/banners/.* - A simple example that uses the common combination of "." and "
1667 *" to denote any character, zero or more times. In other words, any string at
1668 all. So we start with a literal forward slash, then our regular expression
1669 pattern (".*") another literal forward slash, the string "banners", another
1670 forward slash, and lastly another ".*". We are building a directory path here.
1671 This will match any file with the path that has a directory named "banners" in
1672 it. The ".*" matches any characters, and this could conceivably be more forward
1673 slashes, so it might expand into a much longer looking path. For example, this
1674 could match: "/eye/hate/spammers/banners/annoy_me_please.gif", or just "/
1675 banners/annoying.html", or almost an infinite number of other possible
1676 combinations, just so it has "banners" in the path somewhere.
1678 A now something a little more complex:
1680 /.*/adv((er)?ts?|ertis(ing|ements?))?/ - We have several literal forward
1681 slashes again ("/"), so we are building another expression that is a file path
1682 statement. We have another ".*", so we are matching against any conceivable
1683 sub-path, just so it matches our expression. The only true literal that must
1684 match our pattern is adv, together with the forward slashes. What comes after
1685 the "adv" string is the interesting part.
1687 Remember the "?" means the preceding expression (either a literal character or
1688 anything grouped with "(...)" in this case) can exist or not, since this means
1689 either zero or one match. So "((er)?ts?|ertis(ing|ements?))" is optional, as
1690 are the individual sub-expressions: "(er)", "(ing|ements?)", and the "s". The "
1691 |" means "or". We have two of those. For instance, "(ing|ements?)", can expand
1692 to match either "ing" OR "ements?". What is being done here, is an attempt at
1693 matching as many variations of "advertisement", and similar, as possible. So
1694 this would expand to match just "adv", or "advert", or "adverts", or
1695 "advertising", or "advertisement", or "advertisements". You get the idea. But
1696 it would not match "advertizements" (with a "z"). We could fix that by changing
1697 our regular expression to: "/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/", which
1698 would then match either spelling.
1700 /.*/advert[0-9]+\.(gif|jpe?g) - Again another path statement with forward
1701 slashes. Anything in the square brackets "[]" can be matched. This is using
1702 "0-9" as a shorthand expression to mean any digit one through nine. It is the
1703 same as saying "0123456789". So any digit matches. The "+" means one or more of
1704 the preceding expression must be included. The preceding expression here is
1705 what is in the square brackets -- in this case, any digit one through nine.
1706 Then, at the end, we have a grouping: "(gif|jpe?g)". This includes a "|", so
1707 this needs to match the expression on either side of that bar character also. A
1708 simple "gif" on one side, and the other side will in turn match either "jpeg"
1709 or "jpg", since the "?" means the letter "e" is optional and can be matched
1710 once or not at all. So we are building an expression here to match image GIF or
1711 JPEG type image file. It must include the literal string "advert", then one or
1712 more digits, and a "." (which is now a literal, and not a special character,
1713 since it is escaped with "\"), and lastly either "gif", or "jpeg", or "jpg".
1714 Some possible matches would include: "//advert1.jpg", "/nasty/ads/
1715 advert1234.gif", "/banners/from/hell/advert99.jpg". It would not match
1716 "advert1.gif" (no leading slash), or "/adverts232.jpg" (the expression does not
1717 include an "s"), or "/advert1.jsp" ("jsp" is not in the expression anywhere).
1719 s/microsoft(?!.com)/MicroSuck/i - This is a substitution. "MicroSuck" will
1720 replace any occurrence of "microsoft". The "i" at the end of the expression
1721 means ignore case. The "(?!.com)" means the match should fail if "microsoft" is
1722 followed by ".com". In other words, this acts like a "NOT" modifier. In case
1723 this is a hyperlink, we don't want to break it ;-).
1725 We are barely scratching the surface of regular expressions here so that you
1726 can understand the default Junkbuster configuration files, and maybe use this
1727 knowledge to customize your own installation. There is much, much more that can
1728 be done with regular expressions. Now that you know enough to get started, you
1729 can learn more on your own :/
1731 More reading on Perl Compatible Regular expressions: http://www.perldoc.com/
1732 perl5.6/pod/perlre.html