bionic (5) mailfilterex.5.gz

Provided by: mailfilter_0.8.6-3_amd64 bug

NAME

       mailfilterex - Mailfilter configuration file examples

SYNOPSIS

       $HOME/.mailfilterrc examples

DESCRIPTION

       For  a  description of the rcfile format and its keywords see the mailfilterrc(5) man page or get a basic
       set of options from either the INSTALL file or the doc/ directory of the Mailfilter distribution.

       This man page contains several configuration examples and real-life use cases for the Mailfilter program.

EXAMPLES

       If not stated otherwise, the following examples  assume  you  are  using  extended  Regular  Expressions,
       compared  to Mailfilter's default, basic type. General information on Regular Expressions can be found in
       the regex(7) man page or in any good book on UNIX/POSIX. You could also use  slightly  modified  examples
       from procmail(1) if it is available on your system.

   Filtering Domains
       To  create  a  very restrictive set of filter rules at least two keywords should be used: ALLOW and DENY.
       DENY could match all messages coming from an annoying public mail service, while ALLOW  matches  messages
       from a good friend who also uses this annoying public mailer.

              DENY = "^From:.*public-mail\.com"
              ALLOW = "^From:.*friend@public-mail\.com"

       These two lines are enough to block all but your friend's e-mail from the public-mail.com domain.

   Case Sensivity
       In  general  case-sensivity  is  controlled  by the REG_CASE keyword. Having Mailfilter treat expressions
       case-insensitive is almost always more efficient.

              REG_CASE = "no"
              DENY = "^Subject:.*win money"

       In this example Mailfilter would delete all messages with subject lines like `WIN MONEY', `Win Money'  or
       any other mix of capital and non-capital characters. REG_CASE makes filters ignore the case.

       A more complex set up can be achieved by additionally using the DENY_CASE keyword.

              DENY_CASE = "^Subject:.*BUSINESS"

       In  this  example  only  e-mails  that  have `BUSINESS' in their subject match the filter, even though in
       general Mailfilter ignores the case. So in this example all messages with  `business'  or  `Business'  in
       their subjects would not be affected by this filter.

       Such  an  option  is  very  useful  if you are not interested in commercial bulk mail that offers amazing
       business opportunities, but in all your business partners who contact you by e-mail.

   Defining Friends
       The keyword ALLOW can be used to override any spam filters. Similar to the earlier example ALLOW  defines
       a `friend'.

              ALLOW = "^Subject:.*mailfilter"

       Adding  this  rule  to the rcfile would mean all messages that contain anything about Mailfilter in their
       subject lines can pass the spam filters. But even friends tend to send large e-mails sometimes  to  share
       their  joy  about  the latest joke that just made the round in their office. In such cases a limit can be
       defined that affects particularly `friends'.

              MAXSIZE_ALLOW = 500000

       Setting MAXSIZE_ALLOW to 500000 means no message can be larger than 500 kBytes.  (Scanned  `office-jokes'
       are usually around that size.)

   Negative Message Filters
       In  order to create a very restrictive spam protection it can be more useful sometimes to define which e-
       mails should not be deleted instantly and consequently get rid of messages that can  not  be  matched  to
       this  criterion - rather than vice versa. This can be achieved by using negation. The typical use case is
       looking at the message tags `To:' or `Cc:' of an e-mail.

              DENY <> "^(To|Cc):.*my-email@address\.com"

       Having added such a filter to your personal rule set keeps away a  lot  of  spam  that  is  not  directly
       addressed  to your e-mail account. Since this is a very aggressive way of filtering, you are well advised
       to keep your `friends list' up to date. Also note that the above example, using the logical OR  operator,
       works only with extended Regular Expressions.

   Scores
       Instead of setting up spam filters, it is also possible to define scores which can be accumulated until a
       certain threshold is reached.  This is very  useful  to  delete  advertisements  on  mailing  lists,  for
       instance.  Highscore marks the threshold:

              HIGHSCORE = 100
              SCORE +100 = "^Subject:.*viagra"
              SCORE +100 = "^Content-Type:.*html"
              SCORE -100 = "^(To|From):.*my_mailing_list"

       This  simple  example  is  useful to delete mails with a score greater than 100, i.e. if someone sends an
       HTML mail to my_mailing_list, the message will reach score 0.  However, should  an  HTML  mail  regarding
       Viagra  reach  the  list,  then the message will classify as spam, because it reached an overall score of
       100.

       The MAXSIZE_SCORE keyword can be used to add to the accumulated score for an e-mail.  The following  will
       cause  all  emails  not  directly  addressed  to the recipient and greater than 60000 bytes in size to be
       deleted (a useful way of rejecting many common MS targeted worms and  trojans  which  can  clog  up  your
       inbox).

              HIGHSCORE = 100
              MAXSIZE_SCORE +50 = 60000
              SCORE +50 <> "^(To|Cc):.*my-email@address\.com"

       This is a less aggressive way of dealing with e-mail sizes than the using the MAXSIZE_DENY keyword.  Note
       that this example (by using the expression  (To|Cc):.*my-email@address\.com)  works  only  with  extended
       Regular Expressions.

   General Message Size Limits
       It  is  always  a good idea to define a very general size limit for e-mails.  Mailfilter uses the keyword
       MAXSIZE_DENY for that purpose.

              MAXSIZE_DENY = 200000

       Setting it to 200 kBytes can save you a couple of hours, depending on how much  mail  you  get  everyday.
       Messages bigger than that get deleted on the server, unless they match any of the ALLOW rules. To achieve
       maximum efficiency it makes sense to use both MAXSIZE_DENY and MAXSIZE_ALLOW. No one should block up your
       mail box, no `friends', no others.

       A rule of thumb is to be twice as tolerant towards friends than you are towards anonymous people.

   Dealing with Duplicates
       Most  people want to download a message only once, even though it might have been sent to two or three of
       their accounts at the same time. The simple line

              DEL_DUPLICATES = "yes"

       will take care of duplicates and makes sure that only one copy of a message has to be delivered.

   Normalisation of Message Subjects
       Every now and then some clever sales person comes up with the brilliant idea to wrap spam in funny little
       characters.  If  you  get  a message with a subject line similar to this one `,L.E-G,A.L; ,C.A-B`L`E, .B-
       O`X`', then ordinary filters would fail to detect the junk.

              NORMAL = "yes"

       Adding this directive to the rcfile tells Mailfilter to `normalise' subject strings, i.e. leave  in  only
       the  alpha-numeric  characters  and delete the rest.  `,L.E-G,A.L; ,C.A-B`L`E, .B-O`X`' would then become
       `LEGAL CABLE BOX' which can easily be matched to a spam filter.

       Note that Mailfilter first tries to match the original subject string, before it checks on the normalised
       one.

   Control Mechanism
       Since  Mailfilter  deletes e-mails remotely, before they have to be downloaded into the local machine, it
       is also important to know what is going on while the program is being executed. The least you  should  do
       is define a proper level of verbosity and a log file.

              LOGFILE = "$HOME/logs/mailfilter-`date +"%h%y"'"
              VERBOSE = 3

       Level three is the default verbosity level. Using it, Mailfilter reports information on deleted messages,
       run-time errors and dates to the screen and the log file.

       You can use `command' to embedd shell skripts into your path names.  In the above example it is  used  to
       store log files separately for each month and year.

   Extended Regular Expressions
       For  advanced  applications,  the basic Regular Expressions are typically not sufficient. If you know the
       syntax and usage of the  extended  expressions,  it  is  almost  always  a  good  idea  to  set  REG_TYPE
       accordingly.

              REG_TYPE = "extended"

       Extended  expressions  are  more  flexible,  but  also more sensitive towards syntax errors and the like.
       Examples in this man page all use extended type.

NOTES

       If you are new to Regular Expressions and new to Mailfilter, you might want to experiment a  bit,  before
       you  accidentally  delete messages for real. For such cases Mailfilter provides two keywords. TEST can be
       used to only simulate the deletion of messages and SHOW_HEADERS stores all the e-mail  headers  that  get
       examined by the program.

              TEST = "yes"
              SHOW_HEADERS = "$HOME/logs/mailfilter-headers.txt"

       Use  this  setup  if  you  are  not  yet  comfortable  with the concept of spam filtering. It may help to
       understand Regular Expressions better and how to use them.

SEE ALSO

       mailfilter(1), mailfilterrc(5), procmailrc(5), procmailex(5), regex(7)

       Copyright © 2000-2014 Andreas Bauer <baueran@gmail.com>

       This is free software; see the source for copying  conditions.   There  is  NO  warranty;  not  even  for
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.