
   [1][squidGuard.gif] Configuring squidGuard [config.gif]
   [2]squidGuard is an ultrafast and free filter, redirector and access
   controller for [3]Squid
   By [4]Pål Baltzersen and [5]Lars Erik Håland
   [6]Copyright © 1999-2000, [7]Tele Danmark InterNordia
   This page was last modified 2001-12-18
   
Contents

     [8]The configuration file
     * [9]In general
       
     * [10]The Structure
     * [11]Reserved words
     * [12]Declaration names/lables
     * [13]Breaking long lines
       
     [14]Path declarations
   
     [15]Time space declarations
   
     [16]Source group declarations
   
     [17]Destination group declarations
   
     [18]Rewrite rule group declarations
   
     [19]Access control rule declarations
   
     [20]The database
     * [21]Domainlists
     * [22]URLlists
     * [23]Expressionlists
       
     [24]Tuning hints
   
     [25]Working configuration examples
     * [26]Example 0 - The absolutely minimal do nothing
     * [27]Example 1 - The recommended minimal do nothing
     * [28]Example 2 - Limiting the access to one destination group only
     * [29]Example 3 - Blocking the access for unknown or unprivileged
       clients
     * [30]Example 4 - Blocking inapropriate sites
     * [31]Example 5 - Blocking inapropriate sites for some users and
       blocking unknown clients
     * [32]Example 6 - Blocking inapropriate sites partially with regex
     * [33]Example 7 - Blocking inapropriate sites during business hours
       only
       
[arrow-red.gif] The configuration file

   The default path for the squidGuard configuration file is
   "/usr/local/squidGuard/squidGuard.conf" but another default can be set
   at [34]compile time, and can be changed at [35]runtime. From here
   we'll use squidGuard.conf for short.
   
   Note: The number of configuration options and the flexibility may look
   overwhelming. Don't panic! Concentrate on the options that suits your
   needs. Start with a [36]simple working configuration and extend as
   your needs and experience grows. Don't try to solve everything in your
   first attempt..
   
  [arrow-green.gif] In general
  
    The Structure
    
   The recommended structure for squidGuard.conf is:
   
     [37]Path declarations                 (i.e. logdir and dbhome)  (optional)
     [38]Time space declarations           (i.e. time zones)         (optional)
     [39]Source group declarations         (i.e. clients)            (optional)
     [40]Destination group declarations    (i.e. URLs)               (optional)
     [41]Rewrite rule group declarations                             (optional)
     [42]Access control rule declarations                            (required)
   
   Note: No forward references are allowed! Within this strong limitation
   you may actually chose any structure you prefer.
   
    Reserved words
    
   The following words are reserved in squidGuard.conf and should be
   avoided in declaration names:
       acl             fri             outside         sun             urllist
       anonymous       friday          pass            sunday          user
       date            fridays         redirect        sundays         userlist

       dbhome          ip              rew             thu             wed
       dest            log             rewrite         thursday        wednesda
y
       destination     logdir          sat             thursdays       wednesda
ys
       domain          logfile         saturday        time            weekly
       domainlist      mon             saturdays       tue             within
       else            monday          source          tuesday
       expressionlist  mondays         src             tuesdays
    

   In adition is:
          
   # used to start a comment. Everything from the # to the end of line is
   ignored.
   { } used to delimit the start and end of a group declaration.
   - often used to declare a range (i.e. "from-to" or "from - to").
   
    Declaration names/lables
    
   Declaration names/lables have the same limitations as domainnames
   except _ is allowed too (i.e. [-_.a-z0-9]+). [43]Reserved words should
   be avoided as they may cause unpredictable results.
   
    Breaking long lines
    
   Generally you may break a (long) line by repeating the leading
   keyword. Repeated lines of the same type within a class will bee
   joined when the rule trees are built. So:
   
        src foo {
                ip 1.2.3.4
                ip 2.3.4.5
                
        }
                
   is equivalent to:
          
        src foo {
                ip 1.2.3.4 2.3.4.5
                
        }
                
  [arrow-green.gif] Path declarations
  
   The [44]default for the following directories may be overruled by:
          
   logdir defines the diretory for the standard logfiles
   "squidGuard.error" and "squidGuard.log", and the base for relative
   logfilenames in log rules. The default is "/usr/local/squidGuard/logs"
   but another default can be set at [45]compile time.
   dbhome defines the base for relative list filenames. The default is
   "/usr/local/squidGuard/db" but another default can be set at
   [46]compile time.
   
   Although the defaults can be used silently it is recommended to
   declare these explicitly for clarity. For instance:
     logdir /usr/local/squidGuard/logs
     dbhome /usr/local/squidGuard/db


  [arrow-green.gif] Time space declarations
  
   Time spaces, or zones if you prefer, are declared by:
   
        time name {
                specification
                specification
                ...
                
        }
                
   where specification can be any reasonable combination of:
   
        Days of the week with an optional time constraint for each day:
                weekly {smtwhfa} [HH:MM-HH:MM]
                or
                weekly dayname [...] [HH:MM-HH:MM]
                where s=sun, m=mon, t =tue, w=wed, h=thu, f=fri, a=sat.
                and dayname is one of:
                
                      "mon", "monday", "mondays", (synonymous)
                      "tue", "tuesday", "tuesdays", (synonymous)
                      "wed", etc.
                      
                For instance for monday to friday, mornings and evenings:
                
                      weekly mtwhf 00:00-08:00
                      weekly mtwhf 17:00-24:00
                      
                and for saturdays and sundays:
                
                      weekly as
                      or
                      weekly saturday
                      weekly sunday
                      
        Time of the day:
                weekly * HH:MM-HH:MM
                which is just a special case of [47]weekly.
                For instance:
                
                      weekly * 00:00-08:00
                      weekly * 17:00-24:00
                      
        Dates with an optional time constraint for each date:
                date YYYY-MM-DD [...] [HH:MM-HH:MM ...]
                or
                date YYYY.MM.DD [...] [HH:MM-HH:MM ...]
                where the preferred of the two dateformats is just a
                matter of personal taste.
                For instance for the Ascension Day and the Whit Monday of
                1999:
                
                      date 1999.05.13 1999.05.24
                      
                or for the Ash Wednesday afternoon of 1999:
                
                      date 1999.03.31 12:00-24:00
                      
        Date range with an optional time constraint for each day:
                date YYYY-MM-DD-YYYY-MM-DD [HH:MM-HH:MM ...]
                or
                date YYYY.MM.DD-YYYY.MM.DD [HH:MM-HH:MM ...]
                For instance for the Easter of 1999:
                
                      date 1999.04.01-1999.04.05
                      
        Date wildcard with an optional time constraint:
                date YYYY-MM-DD [HH:MM-HH:MM ...]
                or
                date YYYY.MM.DD [HH:MM-HH:MM ...]
                where YYYY, MM and DD may be an asterisk, "*".
                For instance for the New Year's Day:
                
                      date *.01.01
                      
                and for the Christmas Eve:
                
                      date *.12.24 12:00-24:00
                      
   Note1: The numeric formats are strict (I.e. 08:00 not 8:00 for HH:MM
   etc).
   Note2: Overlaps are OK, and the result is the union.
   
   Thus for instance a Norwegian time space definition for leisure time
   including holidays and short days could look something like:
     time leisure-time {
          weekly   * 00:00-08:00              # night
          weekly   * 17:00-24:00              # evening
          weekly   fridays 16:00-17:00        # weekend
          weekly   saturdays sundays          # weekend
          date     *.01.01                    # New Year's Day
          date     *.05.01                    # Labour Day
          date     *.05.17                    # National Day
          date     *.12.24 12:00-24:00        # Christmas Eve
          date     *.12.25                    # Christmas Day
          date     *.12.26                    # Boxing Day
          date     1999.03.31 12:00.24:00     # Ash Wednesday
          date     1999.04.01-1999.04.05      # Easter
          date     1999.05.13 1999.05.24      # Ascension Day and Whitsun
          date     2000.04.19 12:00.24:00     # Ash Wednesday y2000
          date     2000.04.20-2000.04.24      # Easter y2000
          date     2000.06.01 2000.06.12      # Ascension Day and Whitsun y2000
     }


  [arrow-green.gif] Source group declarations
  
   Source group, or client groups if you prefer, are declared by:
   
        src|source name [within|outside time_space_name] {
                specification
                specification
                ...
                
        }
                
          or
          
        src|source name within|outside time_space_name {
                specification
                specification
                ...
                
        } else {
                specification
                specification
                ...
                
        }
                
   where:
     * src and source are synonymous; use the one you prefer.
     * within and outside sets an optional time constraint to the
       definition.
     * the else part refers to the time constraint.
       
   Time constraints on clientgroups can be used to make these clients
   unknown (i.e. use the default rule) within or outside a given time
   space. Or it can be used to define a usergroup that is expected to
   move between two locations at given times (like office/home)
   
   Specification can be any reasonable combination of:
   
        IP addresses and/or ranges (multiple):
                ip xxx.xxx.xxx.xxx [...]
                or
                ip xxx.xxx.xxx.xxx/nn [...]
                or
                ip xxx.xxx.xxx.xxx/mmm.mmm.mmm.mmm [...]
                or
                ip xxx.xxx.xxx.xxx-yyy.yyy.yyy.yyy [...]
                where:
                
                      xxx.xxx.xxx.xxx is an IP address (host or net, i.e.
                      10.11.12.13 or 10.11.12.0),
                      /nn a net prefix (i.e. /23),
                      mmm.mmm.mmm.mmm is a netmask (i.e. 255.255.254.0)
                      and
                      yyy.yyy.yyy.yyy is a host address (must be >=
                      xxx.xxx.xxx.xxx)
                      
        IP address/range list (single):
                iplist [48]filename
                where:
                
                      filename is either a path relative to [49]dbhome or
                      an absolute path (i.e. /full/path) to a
                      [50]database file.
                      the iplist file format is simply addresses and/or
                      networks separated by a newline as above but
                      without the ip keyword. Thus an iplist for all the
                      private addresses could look something like (Though
                      the preferred use of "iplist" over "ip" is for long
                      lists of WS/PC addresses primarily to reduce the
                      size of the configuration file):
                      
                            10.0.0.0/8
                            172.16.0.0/12
                            192.168.0.0/16
                            
        Domains (multiple):
                domain foo.bar [...]  *)
                where:
                
                      foo.bar is a domain (zone) the domain name (from a
                      reverse lookup on the client addresses) belongs to
                      (directly or as a subdomain).
                      
        Users (multiple):
                user foo [...]  **)
                where:
                
                      foo is a username (from a ident/RFC-931 lookup to
                      the client.
                      
        User list (single):
                userlist [51]filename **)
                where:
                
                      filename is either a path relative to [52]dbhome or
                      an absolute path (i.e. /full/path) to a
                      [53]database file.
                      the userlist file format is simply RFC-931
                      usernames, optionally followed by a `:' and a
                      comment (i.e. /etc/passwd or a .htpasswd file may
                      be used) separated by a newline as in the [54]user
                      declaration but without the user keyword. Thus a
                      userlist could look something like:
                      
                            root
                            administrator
                            foo
                            bar
                            
        Special clientgroup translation log (single):
                log|logfile [anonymous] filename
                
          where:
          
                filename is either a path relative to [55]logdir or an
                absolute path (i.e. /full/path) to a logfile where
                translation for this group should be logged. If the
                anonymous option is specified the logged info is somewhat
                anonymized to protect the individual.
                
   *) The use of domain match for clientsgroups requires Squid is set up
   to do revese lookups on clients.
   **) The use of username match for clientsgroups requires Squid is set
   up to do ident/RFC-931 lookups.
   
   Note1: Overlaps are OK, and the groups are matched in the order they
   are defined.
   Note2: The logical operator between different types within a group
   (ip/domain/user) is AND. The default is any. Thus one of each defined
   type must match but undefined types are ignored.
   
   Thus an administrator client group could look something like:
     src admin within leisure-time {
          ip       10.11.12.13 10.11.12.26    # The administrators home WS/PCs
          domain   ras.teledanmark.no         # The RAS domain
          user     root administrator foo bar # The administrators login names
     } else {
          ip       10.1.1.15 10.1.2.17        # The administrators office WS/PC
s
          domain   lan.teledanmark.no         # The LAN domain
          user     root administrator foo bar # The administrators login names
     }


  [arrow-green.gif] Destination group declarations
  
   Destination group, or target groups if you prefer, are declared by:
   
        dest|destination name [within|outside time_space_name] {
                specification
                specification
                ...
                
        }
                
          or
          
        dest|destination name within|outside time_space_name {
                specification
                specification
                ...
                
        } else {
                specification
                specification
                ...
                
        }
                
   where:
     * dest and destination are synonymous.
     * within and outside sets an optional time constraint to the
       definition.
     * the else part refers to the time constraint.
       
   Time constraints on destinationgroups can be used to make these groups
   void (i.e. ignored) within or outside a given time space.
   
   Specification can be any combination of zero or one of each of:
   
        Domainlist (single):
                domainlist [56]filename
                
        URL list (single):
                urllist [57]filename
                
        Expressionlist (single):
                expressionlist [58]filename
                
          where:
          
                filename is either a path relative to [59]dbhome or an
                absolute path (i.e. /full/path) to a [60]database file.
                
        Special destinationgroup redirect URL (single):
                redirect [302:]url
                
        Special destinationgroup redirect log (single):
                log|logfile [anonymous] filename
                
          where:
          
                filename is either a path relative to [61]logdir or an
                absolute path (i.e. /full/path) to a logfile where
                redirects caused by match of this group should be logged.
                If the anonymous option is specified the logged info is
                somewhat anonymized to protect the individual.
                
   Note1: Overlaps are OK, and the groups are matched in the order they
   are listed in the pass declaration in for the actual clientgroup.
   Note2: The logical operator between different types
   (domainlist/urllist/expressionlist) is OR. The default is void. Thus
   the destinationgroup is matched if one of the defined types match.
   Within a destination group the test order is domainlist, urllist, and
   expressionlist.
   
   Thus an entertainment destination group declaration could look
   something like:
     dest not-business-related outside leisure-time {
          domainlist     entertainment/domains
          urllist        entertainment/urls
          expressionlist entertainment/expressions
     }


  [arrow-green.gif] Rewrite rule group declarations
  
   Rewrite rule groups, or rewrite rule sets if you prefer, are declared
   by:
   
        rew|rewrite name [within|outside time_space_name] {
                substitution
                substitution
                ...
                [logging]
                
        }
                
          or
          
        rew|rewrite name within|outside time_space_name {
                substitution
                substitution
                ...
                [logging]
                
        } else {
                substitution
                substitution
                ...
                [logging]
                
        }
                
   where:
     * rew and rewrite are synonymous.
     * within and outside sets an optional time constraint to the
       definition.
     * the else part refers to the time constraint.
       
   Time constraints on rewritegroups can be used to make these groups
   functional within or outside a given time space only; Like redirect to
   local copies within peek business hours.
   
   Substitution is sed style (multiple):
   
          s@from@to@[irR]
          
   where:
          from is a [62]regular expression that will be replaced with the
          string to.
          the i option makes the from part match case insensitive.
          the r option makes the redirection visible to the user with a
          [63]HTTP code 302 - Moved Temporarily (The default is to make
          Squid silently fetch the alternate URL).
          the R option makes the redirection visible to the user with a
          [64]HTTP code 301 - Moved Permanently.
          
   and logging is (single):
          log|logfile [anonymous] filename
          where:
          
                filename is either a path relative to [65]logdir or an
                absolute path (i.e. /full/path) to a logfile where
                succeded rewrites should be logged. If the anonymous
                option is specified the logged info is somewhat
                anonymized to protect the individual.
                
   Note1: Sed style substitutions uses regular expressions and thus slows
   down squidGuard more than B-tree lookups.
   Note2: Suport for visible redirects (i.e. 302: URL prefix) is broken
   in some versions of Squid.
   
   A rewrite rule set declaration could look something like:
     rew get-local {
          s@.*/cb32e46.exe$@http://ftp/pub/www/client/windows/cb32e46.exe@r
          s@.*/cc32e46.exe$@http://ftp/pub/www/client/windows/cc32e46.exe@r
          s@.*/cp32e46.exe$@http://ftp/pub/www/client/windows/cp32e46.exe@r
     }


  [arrow-green.gif] Access Control Lists
  
   The Access Control List, ACL, combies the previous definitions into
   distinct rulesets for each clientgroup:
   
        acl {
                sourcegroupname [within|outside timespacename] {
                
                      [66]pass [!]destgroupname [...]
                      [[67]rew|rewrite rewritegroupname [...]
                      [[68]redirect [301:|302:]new_url]
                      
                }
                sourcegroupname within|outside timespacename {
                
                      [69]pass [!]destgroupname [...]
                      [[70]rew|rewrite rewritegroupname [...]
                      [[71]redirect [301:|302:]new_url]
                      
                } else {
                
                      [72]pass [!]destgroupname [...]
                      [[73]rew|rewrite rewritegroupname [...]
                      [[74]redirect [301:|302:]new_url]
                      
                }
                ...
                [75]default [within|outside timespacename] {
                
                      [76]pass [!]destgroupname [...]
                      [[77]rew|rewrite rewritegroupname [...]
                      [78]redirect [301:|302:]new_url
                      
                }[ else {
                
                      [79]pass [!]destgroupname [...]
                      [[80]rew|rewrite rewritegroupname [...]
                      [81]redirect [301:|302:]new_url
                      
                ]
                
        }
                
   Note: There may be no more than one acl block.
   
   The default rule set: 
   
   The default section defines fallbacks for all acl rulesets. Thus if
   you define a rewrite rule here it will be used in acls where there are
   no rewrite rules defined. (i.e. the other acls inherits the
   definitions in the default acl optionally overruled by own
   definitions). The default rule set is used for all clients that match
   no clientgroup and for clientgroups with no acls declared.
   
   The pass rule: 
   
   The pass rules declares destination groups that should pass for the
   actual client group. "!" is the NOT operator and indicates a
   destination group that should not pass (i.e. be redirected to the
   actual [82]redirect URL).
   Note: Pass rules ends with an implicit "all". It is good practice to
   allways en the pass rules with either "all" or "none" to make them
   clear. Ie. use:
     pass good none
   or
     pass good !bad all
   Note: If there is a !group there must also be a redirect definition
   for eiter that destination group, the actual acl or the default acl.
   If you want some rules for unknown clients that should not apply to
   the other acls you should define a last clientgroup named "unknown"
   and with an IP range 0.0.0.0/0 (i.e. any), and put those rules in the
   "unknown" acl.
   
   Built in wildcard groups:
   
   The following are built in wildcard destination groups:
          
        in-addr
                !in-addr can be used to enforce the use of domainnames
                over IP addresses in the host part of URLs. in-addr is a
                fast equivalent to a group with the expressionlist
                "^[^:/]+://[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9
                ]\{1,3\}($|[:/])".
                
        any
                matches any URL and is a fast equivalent to the
                expression ".*".
                
        all
                is a synonym to any. Use the one you prefer.
                
        none
                is a fast equivalent to !any and should be used to
                terminate pass rules where only the listed destination
                groups should pass.
                
   The rewrite rule: 
   
   The rewrite rules declares the substitution rulsets that applies to
   the actual acl.
   
   The redirect rule: 
   
   The redirect rules declares the altenative URL to be used for blocked
   destination groups (!groups) for the actual acl.
   Note: Inside an acl, this is a fallback used when there is no special
   redirect declared for the actual destination group, and the default
   redirect is the last resort.
   
   squidGuard can do runtime string substitutions in the redirectors.
   Therefor the character "%" has special meaning in the redirector URLs:
   
   %a is replaced with IP address of the client.
   %n is replaced with the domainname of the client or "unknown" if not
   available.
   %i is replaced with the user ID (RFC931) or "unknown" if not
   available.
   %s is replaced with the matched source group (client group) or
   "unknown" if no groups were matched.
   %t is replaced with the matched destination group (target group) or
   "unknown" if no groups were matched.
   %u is replaced with the requested URL.
   %p is replaced with the REQUEST_URI, i.e. the path and the optional
   query string of %u, but note for convenience without the leading "/".
   %% is replaced with a single "%".
   
   Thus you can pass usefull information to a more or less intelligent
   CGI page:
     http://proxy/cgi/squidGuard?clientaddr=%a&clientname=%n&clientident=%i&cli
entgroup=%s&destinationgroup=%t&url=%u


   For a start, there is a sample of such a script in
   samples/squidGuard.cgi in the source tree.
   
[arrow-red.gif] The database

   squidGuard uses a database that can be devided into an unlimited
   number of distinct categories like "local", "customers", "vendors",
   "banners", "banned" etc. Each category may consist of separate
   unlimited lists of [83]domains, [84]URLs and/or [85]regular
   expressions. For easy revision the lists are stored in separate plain
   text files that. The lists are for efficiency stored in in-memory-only
   B-trees at startup.
   
   Note: All URLs are converted to lowercase before match search. So the
   lists should not contain uppercase leters.
   
  [arrow-green.gif] Domainlists
  
   The domainlist file format is simply domainnames/zonenames separated
   by a newline. The length of these lists have neglectable influence on
   the performance.
   
   For instance a start for a financial category:
     amex.com
     asx.com.au
     bourse-de-paris.fr
     exchange.de
     londonstockex.co.uk
     nasdaq.com
     nyse.com
     ose.no
     tse.or.jp
     xsse.se


   Note: squidGuard will match any URL with the domainname itself an any
   subdomains and hosts (i.e. amex.com, www.amex.com, whatever.amex.com
   and www.what.ever.amex.com but not .*[^.]amex.com (i.e. aamex.com
   etc.)).
   
  [arrow-green.gif] URLlists
  
   The urllist file format is simply URLs separated by newline but with
   the "proto://((www|web|ftp)[0-9]*)?" and "(:port)?" parts and normally
   also the ending "(/|/[^/]+\.[^/]+)$" part (i.e. ending "/" or
   "/filename") choped off. (i.e. "[DEL: http://www3. :DEL]
   foo.bar.com[DEL: :8080 :DEL] /what/ever[DEL: /index.html :DEL] " =>
   "foo.bar.com/what/ever")
   
   For instance a category for banned sites:
     foo.com/~badguy
     bar.com/whatever/suspect


   Note: The removed parts above are ignored by squidGuard in URL
   matching. Thus all these URLs will match the above urllist:
     http://foo.com/~badguy
     http://foo.com/~badguy/whatever
     ftp://foo.com/~badguy/whatever
     wais://foo.com/~badguy/whatever
     http://www2.foo.com/~badguy/whatever
     http://web56.foo.com/~badguy/whatever


   but not:
     http://barfoo.com/~badguy
     http://bar.foo.com/~badguy
     http://foo.com/~goodguy


   New in 1.0.0 is the ability to do 1-1 redirects on url basis with
   "key new_url". Thus as an alternative to using rewrites to redirect to
   local distributions you can have a destination group with an urllist
   like:
     netscape.com/pub/communicator/4.51/english/windows/windows95_or_nt/complet
e_install/cc32e451.exe http://ftp.teledanmark.no/pub/www/client/windows/cc32e45
1.exe
     netscape.com/pub/communicator/4.51/english/windows/windows95_or_nt/base_in
stall/cb32e451.exe http://ftp.teledanmark.no/pub/www/client/windows/cb32e451.ex
e


   and an acl with pass ... !download .... This may be a faster
   alternative than using lots of s@from@to@ rewrites for 1-1 mapping
   since it will be faster to search the B-tree than perform a bunch of
   string edits.
   
  [arrow-green.gif] Expressionlists
  
   The expressionlist file format is lines with regular expressions as
   described in regex(5). Of most interrest is:
   
   . Matches any single character (use "\." to match a ".").
   [abc] Matches one of the characters ("[abc]" matches a single "a" or
   "b" or "c").
   [c-g] Matches one of the characters in the range ("[c-g]" matches a
   single "c" or "d" or "e" or "f" or "g".
   "[a-z0-9]" matches any single letter or digit.
   "[-/.:?]" matches any single "-" or "/" or "." or ":" or "?".).
   ? None or one of the preceding ("words?" will match "word" and
   "words".
   "[abc]?" matches a single "a" or "b" or "c" or nothing (i.e. "")).
   * None or more of the preceding ("words*" will match "word", "words"
   and "wordsssssss". ".*" will match anything including nothing).
   + One or more of the preceding ("xxx+" will match a sequence of 3 or
   more "x").
   (expr1|expr2) One of the expressions, which in turn may contain a
   similar construction ("(foo|bar)" will match "foo" or "bar".
   "(foo|bar)? will match "foo" or "bar" or nothing (i.e. "")).
   $ The end of the line ("(foo|bar)$" will match "foo" or "bar"only at
   the end of a line).
   \x Disable the special meaning of x where x is one of the special
   regex characters ".?*+()^$[]{}\"  ("\." will match a single ".", "\\"
   a single "\" etc.)
   
   Thus a start to block possible sexual material by expression match
   could look like:
   
          (^|[-\?+=/_])(bondage|boobs?|busty?|hardcore|porno?|sex|xxx+)([
          -\?+=/_]|$)
          
   Notes:
     * Unless you build your expressions very very carefully there is a
       high risk you will have annoyed users on your neck. Typically you
       might accidentally block "Essex", "Sussex", "breastcancer",
       "www.x.org" etc. in your eagerness for blocking pornographic
       material. In practice you would probably replace some of the words
       in the example above with some more clearly pornographic related
       words that I don't find appropriate to list here.
     * While the size of the domain and urllists only has marginal
       influence on the performance, too many large or complex
       expressions will quickly degrade the performance of squidGuard.
       Though it may depend heavily on the performance of the regex
       library you link with.
     * There is a rich set of sample files for a group of supposedly
       pornographic sites under samples/dest/adult in the source tree
       that you can use as a start if porn blocking is one of your tasks.
       Please note: We recommend that you review these lists before using
       them. Those domains and urls have been collected automagically by
       a robot. No manual evaluation of the corresponding contents has
       been performed. Therefor there is a chance some nonpornographic
       sites have sliped in. Please [86]report such errors but don't
       blame us if your fine site is on the list. (Blame those who have
       pointers to appropriate sites mixed in on their heavy porn link
       pages!)
     * To avoid publishing to your users a complete guide to banned
       sites, you probably want to have some or all of these files
       protected by for instance:
       
                chmod 640 /wherever/filter/db/dest/adult/*
                chown cache_effective_user /wherever/filter/db/dest/adult
                /*
                chgrp cache_effective_group /wherever/filter/db/dest/adul
                t/*
                
       where cache_effective_user and cache_effective_group are the
       values for the corresponding tags as defined in squid.conf.
       
  [arrow-green.gif] Prebuilt databases
  
    Creating a prebuilt database
    
   To convert a domainlist or urllist from plain text file to a prebuilt
   database use:
   
          squidGuard -C listfile
          
   and send Squid a HUP signal to respawn squidGuard. Note: listfile is
   the absolute plain text filename or relative to dbhome.
   
    Updating a prebuilt database
    
   To add and remove entries from a prebuilt database in runtime put the
   changes in a diff file (file.diff for file.db) with the following
   simple format:
   
          +new
          -old
          ...
          
   Then use:
   
          squidGuard -u
          
   and remove the diff files. The changes should take effect immediately.
   
[arrow-red.gif] Tuning hints

   For optimal performance try:
     * limiting both the number of regular expressions and their
       complexity. Use domainlists and/or urllists where possible.
     * limiting the number of rewrite rules. Use redirectors where
       possible.
     * limiting the number of useless url list entries. Move the
       domainnames to the domainlist and remove redundant urllist entries
       where aplicable.
     * using ip addressranges rather than long lists of single ip
       addresses. If possible try grouping different usergroups into
       different ranges or subnets (virtual or physical).
       
[arrow-red.gif] Working configuration examples

  [arrow-green.gif] [87]Example 0 - The absolutely minimal do nothing config:
  
   The absolutely minimal config file is an emty but existing file (i.e.
   squidGuard -c /dev/null) which is equivalent to:
     acl {
          default {
               pass all
          }
     }


  [arrow-green.gif] [88]Example 1 - The recommended minimal do nothing config:
  
   We do recommend, for clarity, to say explicitly what squidGuard is
   expected to do (makes things less magic for a new operator):
     logdir /usr/local/squidGuard/log

     acl {
         default {
             pass all
         }
     }


  [arrow-green.gif] [89]Example 2 - Limiting the access to one destination
  group only:
  
     logdir /usr/local/squidGuard/log
     dbhome /usr/local/squidGuard/db

     dest local {
         domainlist local/domains
     }

     acl {
         default {
             pass local none
             redirect http://localhost/cgi/blocked?clientaddr=%a&clientname=%n&
clientuser=%i&clientgroup=%s&url=%u
         }
     }


   This implies there must be a domain list file
   "[90]/usr/local/squidGuard/db/local/domains" that may simply look
   like:
     teledanmark.no


  [arrow-green.gif] [91]Example 3 - Blocking the access for unknown or
  unprivileged clients:
  
     logdir /usr/local/squidGuard/log
     dbhome /usr/local/squidGuard/db

     src privileged {
         ip     10.0.0.1 10.0.0.73 10.0.0.233   # ONE OF single clients
         ip     10.0.0.10-10.0.0.20             # OR WITHIN range 10.0.0.10 - 1
0.0.0.20
         ip     10.0.1.32/27                    # OR WITHIN range 10.0.1.32 - 1
0.0.1.63
         ip     10.0.2.0/255.255.255.0          # OR WITHIN range 10.0.2.0  - 1
0.0.2.255
                                                # AND
         domain foo.bar                         # MATCH foo.bar. OR *.foo.bar.
     }

     acl {
         privileged {
             pass all
         }

         default {
             pass none
             redirect http://info.foo.bar/cgi/blocked?clientaddr=%a&clientname=
%n&clientuser=%i&clientgroup=%s&url=%u
         }
     }


   Using client domainname match implies reverse lookup is enabled
   (log_fqdn on) in squid.conf.
     teledanmark.no


  [arrow-green.gif] [92]Example 4 - Blocking inappropriate sites:
  
     logdir /usr/local/squidGuard/log
     dbhome /usr/local/squidGuard/db

     dest porn {
         domainlist porn/domains
         urllist    porn/urls
     }

     acl {
         default {
             pass !porn all
             redirect http://localhost/cgi/blocked?clientaddr=%a&clientname=%n&
clientuser=%i&clientgroup=%s&url=%u
         }
     }


   This implies there must be a domain list file
   "[93]/usr/local/squidGuard/db/porn/domains" and a domain list file
   "[94]/usr/local/squidGuard/db/porn/urls". The [95]domain list file may
   have a zillion lines like:
     porn.com
     sex.com


   The "[96]url list file may have an other zillion lines like:
     foo.com/~porn
     bar.com/img/sex


  [arrow-green.gif] [97]Example 5 - Blocking inappropriate sites for some users
  and blocking unknown clients:
  
     logdir /usr/local/squidGuard/log
     dbhome /usr/local/squidGuard/db

     src grownups {
         ip        10.0.0.0/24    # range 10.0.0.0  - 10.0.0.255
                               # AND
         user   foo bar   # ident foo or bar
     }

     src kids {
         ip        10.0.0.0/22    # range 10.0.0.0 - 10.0.3.255
     }

     dest porn {
         domainlist porn/domains
         urllist    porn/urls
     }

     acl {
         grownups {
             pass all
         }

         kids {
             pass !porn all
         }

         default {
             pass none
             redirect http://info.foo.bar/cgi/blocked?clientaddr=%a&clientname=
%n&clientuser=%i&clientgroup=%s&targetgroup=%t&url=%u
         }
     }


   Using userident match implies RFC931/ident lookup is enabled in
   squid.conf, optionally only for the actual client groups, and that foo
   and bar's workstations must [98]support RFC931.
   
  [arrow-green.gif] [99]Example 6 - Blocking inappropriate sites partially with
  regex:
  
    + ensuring local and good sites are passed even if they would match a
   blocking regex:
    + limiting the usage of IP-address URLs:
     logdir /usr/local/squidGuard/log
     dbhome /usr/local/squidGuard/db

     dest local {
         domainlist     local/domains
     }

     dest good {
         domainlist     local/domains
     }

     dest porn {
         domainlist     porn/domains
         urllist        porn/urls
         expressionlist porn/expressions
     }

     acl {
         default {
             pass local good !in-addr !porn all
             redirect http://localhost/cgi/blocked?clientaddr=%a&clientname=%n&
clientuser=%i&clientgroup=%s&url=%u
         }
     }


  [arrow-green.gif] [100]Example 7 - Blocking inappropriate sites within
  business hours only:
  
   Lets extend [101]example 5 with:
     * a time constraint on censorship
     * logging redirections of inappropriate sites anonymized
     * redirecting inappropriate sites specially.
     * and still protecting the kids 24h.
       
     logdir /usr/local/squidGuard/log
     dbhome /usr/local/squidGuard/db

     time leisure-time {
         weekly * 00:00-08:00 17:00-24:00       # night and evening
         weekly fridays 16:00-17:00             # weekend
         weekly saturdays sundays               # weekend
         date   *.01.01                         # New Year's Day
         date   *.05.01                         # Labour Day
         date   *.05.17                         # National Day
         date   *.12.24 12:00-24:00             # Christmas Eve
         date   *.12.25                         # Christmas Day
         date   *.12.26                         # Boxing Day
         date   1999.03.31 12:00.24:00          # Ash Wednesday
         date   1999.04.01-1999.04.05           # Easter
         date   1999.05.13 1999.05.24           # Ascension Day and Whitsun
         date   2000.04.19 12:00.24:00          # Ash Wednesday y2000
         date   2000.04.20-2000.04.24           # Easter y2000
         date   2000.06.01 2000.06.12           # Ascension Day and Whitsun y20
00
     }

     src grownups {
         ip     10.0.0.0/24                     # range 10.0.0.0  - 10.0.0.255
                                                # AND
         user   foo bar                         # ident foo or bar
     }

     src kids {
         ip     10.0.0.0/22                     # range 10.0.0.0 - 10.0.3.255
     }

     dest porn {
         domainlist     porn/domains            # file listing domains  (clear
text)
         urllist        porn/urls               # file listing URLs     (clear
text)
         expressionlist porn/expressions        # file with expressions (clear
text regex)
         redirect       302:http://info.foo.bar/images/blocked.gif
                                                # redirect matches to this URL
         log anonymous  porn.log                # log redirects anonymized to l
ogdir/porn.log
     }

     acl {
         grownups within leisure-time {
             pass all                           # don't censor peoples leisure-
time
         } else {
             pass !in-addr !porn all            # restrict access during busine
ss hours
         }

         kids {
             pass !porn all                     # protect the kids 24h anyway
         }

         default {
             pass none                          # reject unknown clients
             redirect http://info.foo.bar/cgi/blocked?clientaddr=%a&clientname=
%n&clientuser=%i&clientgroup=%s&targetgroup=%t&url=%u
         }
     }

                        ____________________________
   
      [102][gnu-logo.gif] [103][perl-logo.gif] [104][solaris-logo.gif]
                  [105][sun-logo.gif] [106][tdi-logo.gif] 
                                      
    [107][apache-logo.gif] [108][squid-logo.gif] [109][squidGuard.gif] 
                                      
                             [110][identd.gif] 

References

   1. http://ftp.teledanmark.no/pub/www/proxy/squidGuard/
   2. http://www.squidguard.org/
   3. http://www.squid-cache.org/
   4. http://www.squidguard.org/authors/
   5. http://www.squidguard.org/authors/
   6. http://www.squidguard.org/copyright/
   7. http://www.teledanmark.no/
   8. http://www.squidguard.org/config/#Configuration_file
   9. http://www.squidguard.org/config/#General
  10. http://www.squidguard.org/config/#Structure
  11. http://www.squidguard.org/config/#Reserved
  12. http://www.squidguard.org/config/#Lables
  13. http://www.squidguard.org/config/#Breaking
  14. http://www.squidguard.org/config/#Directories
  15. http://www.squidguard.org/config/#Timespace
  16. http://www.squidguard.org/config/#Sourcegroups
  17. http://www.squidguard.org/config/#Destinationgroups
  18. http://www.squidguard.org/config/#Rewritegroups
  19. http://www.squidguard.org/config/#Acls
  20. http://www.squidguard.org/config/#Lists
  21. http://www.squidguard.org/config/#Domainlists
  22. http://www.squidguard.org/config/#URLlists
  23. http://www.squidguard.org/config/#Expressionlists
  24. http://www.squidguard.org/config/#Tuning
  25. http://www.squidguard.org/config/#Examples
  26. http://www.squidguard.org/config/#Minimal
  27. http://www.squidguard.org/config/#example01
  28. http://www.squidguard.org/config/#example02
  29. http://www.squidguard.org/config/#example03
  30. http://www.squidguard.org/config/#example04
  31. http://www.squidguard.org/config/#example05
  32. http://www.squidguard.org/config/#example06
  33. http://www.squidguard.org/config/#example07
  34. http://www.squidguard.org/install/#Defaultconfigfile
  35. http://www.squidguard.org/install/#Configfile
  36. http://www.squidguard.org/config/#example01
  37. http://www.squidguard.org/config/#Directories
  38. http://www.squidguard.org/config/#Timespace
  39. http://www.squidguard.org/config/#Sourcegroups
  40. http://www.squidguard.org/config/#Destinationgroups
  41. http://www.squidguard.org/config/#Rewritegroups
  42. http://www.squidguard.org/config/#Acls
  43. http://www.squidguard.org/config/#Reserved
  44. http://www.squidguard.org/config/#Logdir
  45. http://www.squidguard.org/install/#Logdir
  46. http://www.squidguard.org/install/#DBhome
  47. http://www.squidguard.org/config/#Weekly
  48. http://www.squidguard.org/config/#IPlists
  49. http://www.squidguard.org/config/#DBhome
  50. http://www.squidguard.org/config/#IPlists
  51. http://www.squidguard.org/config/#Userlists
  52. http://www.squidguard.org/config/#DBhome
  53. http://www.squidguard.org/config/#Userlists
  54. http://www.squidguard.org/config/#User
  55. http://www.squidguard.org/config/#Logdir
  56. http://www.squidguard.org/config/#Domainlists
  57. http://www.squidguard.org/config/#URLlists
  58. http://www.squidguard.org/config/#Expressionlists
  59. http://www.squidguard.org/config/#DBhome
  60. http://www.squidguard.org/config/#Lists
  61. http://www.squidguard.org/config/#Logdir
  62. http://www.squidguard.org/config/#Regular expressions
  63. http://ftp.teledanmark.no/pub/networking/rfc/rfc1945.txt
  64. http://ftp.teledanmark.no/pub/networking/rfc/rfc1945.txt
  65. http://www.squidguard.org/config/#Logdir
  66. http://www.squidguard.org/config/#Pass
  67. http://www.squidguard.org/config/#Rewrite
  68. http://www.squidguard.org/config/#Redirect
  69. http://www.squidguard.org/config/#Pass
  70. http://www.squidguard.org/config/#Rewrite
  71. http://www.squidguard.org/config/#Redirect
  72. http://www.squidguard.org/config/#Pass
  73. http://www.squidguard.org/config/#Rewrite
  74. http://www.squidguard.org/config/#Redirect
  75. http://www.squidguard.org/config/#Default
  76. http://www.squidguard.org/config/#Pass
  77. http://www.squidguard.org/config/#Rewrite
  78. http://www.squidguard.org/config/#Redirect
  79. http://www.squidguard.org/config/#Pass
  80. http://www.squidguard.org/config/#Rewrite
  81. http://www.squidguard.org/config/#Redirect
  82. http://www.squidguard.org/config/#Redirect
  83. http://www.squidguard.org/config/#Domainlists
  84. http://www.squidguard.org/config/#URLlists
  85. http://www.squidguard.org/config/#Expressionlists
  86. mailto:squidguard@squidguard.org?subject=squidGuard%20blacklist%20error
  87. http://www.squidguard.org/config/examples/00.conf
  88. http://www.squidguard.org/config/examples/01.conf
  89. http://www.squidguard.org/config/examples/02.conf
  90. http://www.squidguard.org/config/examples/02.domains
  91. http://www.squidguard.org/config/examples/03.conf
  92. http://www.squidguard.org/config/examples/04.conf
  93. http://www.squidguard.org/config/examples/04.domains
  94. http://www.squidguard.org/config/examples/04.urls
  95. http://www.squidguard.org/config/examples/04.domains
  96. http://www.squidguard.org/config/examples/04.urls
  97. http://www.squidguard.org/config/examples/05.conf
  98. http://www.squidguard.org/links/#Identd
  99. http://www.squidguard.org/config/examples/06.conf
 100. http://www.squidguard.org/config/examples/07.conf
 101. http://www.squidguard.org/config/#example05
 102. http://www.gnu.org/
 103. http://www.perl.com/pub/
 104. http://www.sun.com/solaris/
 105. http://www.sun.com/servers/
 106. http://www.teledanmark.no/
 107. http://www.apache.org/httpd.html
 108. http://www.squid-cache.org/
 109. http://www.squidguard.org/
 110. http://info.teledanmark.no/freeware/identd/
