View source for Procmail Filter

 <nowiki>procmail-filter.txt____________________________________________________________</nowiki>
 <nowiki>Invoked by sendmail, or a .forward  mechanism,  procmail is a  powerful tool</nowiki>
 <nowiki>to</nowiki>
 <nowiki>use in the task of sorting and filtering mail either system- wide or</nowiki>
 <nowiki>customized</nowiki>
 <nowiki>for and by each individual user.               Using "procmail" to filter</nowiki>
 <nowiki>email</nowiki>
 <nowiki>Dec 11, 2004                   Based on the FILTERING MAIL FAQ by Nancy</nowiki>
 <nowiki>McGough </nowiki>
 <nowiki>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~</nowiki>
 <nowiki></nowiki>
 <nowiki>(DEMO ONE) NON-PRIVILEGED SHELL USER:  Procmail + Pine</nowiki>
 <nowiki>```````````````````````````````````````````````````````````</nowiki>
 <nowiki>Typical system shell account user may use procmail to sort email for viewing</nowiki>
 <nowiki>with pine.  This also works for mutt and other email applications with a few</nowiki>
 <nowiki>minor adjustments to the default paths.</nowiki>
 <nowiki></nowiki>
 <nowiki>By default pine will view messages directly from the spool/mail unless a local</nowiki>
 <nowiki>'mbox' has been created (touch ~/mbox).  If mbox exists then pine transfers</nowiki>
 <nowiki>messages from spool/mail to ~/mbox for viewing.</nowiki>
 <nowiki></nowiki>
 <nowiki>In pine create directors to have email sorted to automatically.  (L) for</nowiki>
 <nowiki>folder list and (A) to add folder.  For this example create a folder with the</nowiki>
 <nowiki>name 'sample' for email from sample@yahoo.com.</nowiki>
 <nowiki></nowiki>
 <nowiki>Back to the shell prompt create a folder inside $HOME/mail called 'mbox' and</nowiki>
 <nowiki>create a symbolic link to it from $HOME so that...</nowiki>
 <nowiki></nowiki>
 <nowiki>  touch ~/mbox</nowiki>
 <nowiki>  ln -s ~/mail/mbox ~/mbox</nowiki>
 <nowiki></nowiki>
 <nowiki>This satisfies pine to find mbox where it expects it to be and satisfies our</nowiki>
 <nowiki>procmail script to find mbox in a more logical location.</nowiki>
 <nowiki></nowiki>
 <nowiki>Under user home 'touch .procmailrc' and 'touch .forward', ensure permissions</nowiki>
 <nowiki>are set 644.  Now 'vi .forward' and insert the following line:</nowiki>
 <nowiki></nowiki>
 <nowiki>  "|IFS=' ' && p=/usr/bin/procmail && test -f $p && exec $p -Yf- || exit 75</nowiki>
 <nowiki>#username"</nowiki>
 <nowiki></nowiki>
 <nowiki>observing the correct path to 'procmail' (find it 'locate procmail|grep bin')</nowiki>
 <nowiki>if you have to.  observe that after the pound character change 'username' to</nowiki>
 <nowiki>the actual shell user.</nowiki>
 <nowiki></nowiki>
 <nowiki>Edit 'vi .procmailrc' and insert:</nowiki>
 <nowiki></nowiki>
 <nowiki>  PATH=$HOME/bin:/usr/bin:/usr/ucb:/bin:/usr/local/bin:.</nowiki>
 <nowiki>  MAILDIR=$HOME/mail      # You'd better make sure it exists</nowiki>
 <nowiki>  DEFAULT=$MAILDIR/mbox</nowiki>
 <nowiki>  LOGFILE=$HOME/maillog</nowiki>
 <nowiki>  LOCKFILE=$HOME/.lockmail</nowiki>
 <nowiki></nowiki>
 <nowiki>  :0                              </nowiki>
 <nowiki>  * ^From.*sample@*yahoo.com</nowiki>
 <nowiki>  $MAILDIR/sample </nowiki>
 <nowiki></nowiki>
 <nowiki>Ok, now your regular mail goes to pine mbox and anything from sample@yahoo.com</nowiki>
 <nowiki>is sorted and placed in the pine mail folder 'sample'.</nowiki>
 <nowiki>note that :0 is colon + zero (if your term zero and letter O visibly alike)</nowiki>
 <nowiki></nowiki>
 <nowiki></nowiki>
 <nowiki>(DEMO TWO) PROCMAIL RULE CONFIGURATION: sample procmail filter rules</nowiki>
 <nowiki>```````````````````````````````````````````````````````````</nowiki>
 <nowiki>example 1: to make all mail from kit@notes.unl.edu go into pine's kit folder.</nowiki>
 <nowiki></nowiki>
 <nowiki>  :0:</nowiki>
 <nowiki>  * ^From:.kit@notes.unl.edu</nowiki>
 <nowiki>  $MAILDIR/kit</nowiki>
 <nowiki></nowiki>
 <nowiki>example 2: anyone who has the text string 'lisa' as any part of the email</nowiki>
 <nowiki>address will go into the alllisa folder.</nowiki>
 <nowiki></nowiki>
 <nowiki>  :0:</nowiki>
 <nowiki>  * ^From:.*lisa</nowiki>
 <nowiki>  $MAILDIR/alllisa </nowiki>
 <nowiki></nowiki>
 <nowiki>example 3: you are on a maillist were all messages say they are To:</nowiki>
 <nowiki>'listmembers@linuxchix.org' and sort them into pine's linuxchix folder.</nowiki>
 <nowiki></nowiki>
 <nowiki>  :0:</nowiki>
 <nowiki>  * ^To:.*linuxchix</nowiki>
 <nowiki>  $MAILDIR/linuxchix</nowiki>
 <nowiki></nowiki>
 <nowiki>example 4: there are various text stings that may appear in spam, one I see a</nowiki>
 <nowiki>lot is "mortgage" as in "lower your mortgage rate" and I want anything that</nowiki>
 <nowiki>mentions 'mortgage' in the Subject line to go into pine's spambox folder.</nowiki>
 <nowiki></nowiki>
 <nowiki>  :0:</nowiki>
 <nowiki>  * ^Subject:.*mortgage</nowiki>
 <nowiki>  $MAILDIR/spambox</nowiki>
 <nowiki></nowiki>
 <nowiki>example 5: anything from people at uunet will go to pine's uunetbox folder</nowiki>
 <nowiki></nowiki>
 <nowiki>  :0                 </nowiki>
 <nowiki>  * ^From.*@uunet</nowiki>
 <nowiki>  $MAILDIR/uunetbox</nowiki>
 <nowiki></nowiki>
 <nowiki></nowiki>
 <nowiki>(DEMO THREE) NON-PRIVILEGED SHELL USER:  Procmail Whitelisting</nowiki>
 <nowiki>```````````````````````````````````````````````````````````</nowiki>
 <nowiki>Whitelist mail filtering works by considering anything (sender) that is not in</nowiki>
 <nowiki>your list bulk email or spam.  Put your friends and family in your white list</nowiki>
 <nowiki>so that their messages go to your inbox while anything else goes into a bulk</nowiki>
 <nowiki>mail folder because it is likely spam.  Then on a rainy day you can speed</nowiki>
 <nowiki>glance though the bulk mail folder and zap most of it, perhaps only stopping</nowiki>
 <nowiki>on occasion to look in a message that could potentially be something you want</nowiki>
 <nowiki>or a forgotten friend that you need to add to the white list.</nowiki>
 <nowiki></nowiki>
 <nowiki>This example the white-list is read by procmail.  Whitelist contains only</nowiki>
 <nowiki>addresses you want in the inbox, everything else sent to bulkmail.</nowiki>
 <nowiki></nowiki>
 <nowiki>  # filter mail against current whitelist</nowiki>
 <nowiki>  FROM=`formail -XFrom: | formail -r -xTo: | tr -d ' '`</nowiki>
 <nowiki>  :0</nowiki>
 <nowiki>  * ! ? grep -F -i -x -q "$FROM" $HOME/.whitelist</nowiki>
 <nowiki>  $MAILDIR/bulkmail</nowiki>
 <nowiki></nowiki>
 <nowiki>An additional mechanism should be added to notify individuals sending messages</nowiki>
 <nowiki>with a response option for the white list. (visit: white list spam)</nowiki>
 <nowiki></nowiki>
 <nowiki></nowiki>
 <nowiki>(ADDITIONAL INFORMATION) PROCMAIL RELATED: Comments on using procmail</nowiki>
 <nowiki>```````````````````````````````````````````````````````````</nowiki>
 <nowiki>Determine your version of procmail by executing 'procmail -v'.  If something</nowiki>
 <nowiki>provided here does not work, check to see how _old_ your procmail version is.</nowiki>
 <nowiki></nowiki>
 <nowiki>There are man pages provided for procmail, procmailex, procmailrc, procmailsc,</nowiki>
 <nowiki>and formail with most linux distributions.  You can learn a lot by reading the</nowiki>
 <nowiki>man pages before seeking help on various forums and annoying people because</nowiki>
 <nowiki>you are asking a question that could be answered by reading the man pages.</nowiki>
 <nowiki></nowiki>
 <nowiki>Procmail is not an SMTP agent (it's a LDA, Local Delivery Agent) and cannot be </nowiki>
 <nowiki>used to 'reject' spam during the SMTP transaction.  Although possible to </nowiki>
 <nowiki>bounce potential spam with procmail, it would be illadvised.  Spam headers are </nowiki>
 <nowiki>almost always forged, and the bounce would go to either the wrong place or </nowiki>
 <nowiki>nothingness causing errors in your SMTP agent logs.</nowiki>
 <nowiki></nowiki>
 <nowiki>Apparently, the '.forward' file is only necessary if procmail is not</nowiki>
 <nowiki>configured as the LDA in sendmail or equivalent.</nowiki>
 <nowiki></nowiki>
 <nowiki></nowiki>
 <nowiki>(ADDITIONAL INFORMATION) MAIL FILTERING AND SPAM:  Worth Mentioning</nowiki>
 <nowiki>```````````````````````````````````````````````````````````</nowiki>
 <nowiki>In regards to spam and mail filtering, however, outside the scope of this</nowiki>
 <nowiki>document, none-the-less worth mentioning...</nowiki>
 <nowiki></nowiki>
 <nowiki>Gray-listing is a technique now becoming popular.  Consider it a method with</nowiki>
 <nowiki>the advantages of white-listing but without its short-comings.</nowiki>
 <nowiki>White-listing's</nowiki>
 <nowiki>shortcomings manifest when applied to businesses that rely on email.</nowiki>
 <nowiki>(recommendation:  research 'gray listing' with 'spam')</nowiki>
 <nowiki></nowiki>
 <nowiki>Spamassassin email filtering is very popular in business usage.  It supports</nowiki>
 <nowiki>automatic training, forged message header rejecting, and works using a score</nowiki>
 <nowiki>based approach.</nowiki>
 <nowiki>(recommendation: visit http://spamassassin.apache.org/)</nowiki>
 <nowiki></nowiki>
 <nowiki>Procmail was created by Stephen R. van den Berg and the procmail web site is</nowiki>
 <nowiki>at the address http://www.procmail.org/ .</nowiki>
 <nowiki></nowiki>
 <nowiki>_______________________________________________________________________________</nowiki>
 <nowiki>spam filtering with procmail is distributed by the Star City Linux User Group.</nowiki>
 <nowiki>By LazyGirl & Roach.  Sources mentioned in article.  Contribute Documentation!</nowiki>
 <nowiki></nowiki>

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