How to do email filtering

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					University of Leeds Academic Services


             How to use ISS email
      filtering service to remove spam
                 with Outlook

                       Qin Li
            ISS Email Service Coordinator
                  q.li@leeds.ac.uk
University of Leeds Academic Services



Objectives

   Learn what is ISS email filtering service
   Learn the format of spam tags
   Learn how to set up a basic rule
   Learn to set up exceptions
   Learn how to refine rules
University of Leeds Academic Services



ISS email filtering service

    A system to filter email coming to Leeds
    Running PureMessage, an enterprise
     spam filtering software on dedicated
     servers
    Tags each message with a spam rating
    End users can use email client programs
     such as Outlook to control and remove
     spam messages
University of Leeds Academic Services



Format of spam tags

    Where to find spam tags
    –    [PMX:#...] indicator prefixed to Subject for messages
         rated over 50% spam probability
    –    X-Perlmx-Spam special header
    An example
    –    Subject: [PMX:#####] Your free ticket to …
    –    X-Perlmx-Spam: Gauge=XXXXXXXXXII,
         Probability=92%, Report="BIG_FONT,
         CLICK_BELOW, CTYPE_JUST_HTML,
         FROM_ENDS_IN_NUMS, HEADER_8BITS, …
University of Leeds Academic Services



Format of spam tags (cont’)

    A specific header
    –    X-Perlmx-Spam:
    A gauge
    –    Gauge=XXXXXXXXXII
    A probability in percentage
    –    Probability=92%
    A report
    –    Report="BIG_FONT, CLICK_BELOW,
         CTYPE_JUST_HTML, FROM_ENDS_IN_NUMS,
         HEADER_8BITS, …
University of Leeds Academic Services



Reveal tags in full headers

    Open a message in
     Outlook
    Click ‘View’ menu
    Select ‘Options’
    You will see a
     window similar to the
     picture to the right
    Look in the box
     ‘Internet headers’
University of Leeds Academic Services



Set up a basic rule in Outlook

    Click ‘Tools’ and
     ‘Rules Wizard’
    You will see the
     Rules wizard
     window displayed
    Click New button to
     start building a basic
     rule
University of Leeds Academic Services



Set up a basic rule in Outlook

    Tick the radio button
     next to ‘Start from a
     blank rule
    Select ‘Check
     messages when
     they arrive
    Click Next button to
     continue
University of Leeds Academic Services



Set up a basic rule in Outlook

    Tick the box next to
     ‘with specific words
     in the message
     header’
    Double click the
     under lined word
     ‘Specific words’ to
     continue
University of Leeds Academic Services



Set up a basic rule in Outlook

    Type the exact
     trigger phrase in the
     search text field
    Click Add button to
     add it to the search
     list.
    Click OK to continue
University of Leeds Academic Services



Set up a basic rule in Outlook

    Notice the trigger
     text is displayed in
     the Rule description
     box
    Click Next button to
     continue
University of Leeds Academic Services



Set up a basic rule in Outlook

    Tick the box next to
     the line ‘move it to
     the specified folder’
    Click under lined
     word ‘specified’ to
     open the folder list
University of Leeds Academic Services



Set up a basic rule in Outlook

    Select ‘Spam’ folder,
     or click ‘New’ button
     to create a folder
     called ‘Spam’
    Click OK to continue
University of Leeds Academic Services



Set up an exception

    Tick the box next to
     the line ‘except if
     send is in specified
     address book’
    Double click the
     under lined word
     ‘specified’ to
     continue
University of Leeds Academic Services



Set up an exception

    Select ‘Contacts’
     and then click ‘Add’.
University of Leeds Academic Services



Set up an exception

    You will see
     ‘Contacts’ address
     book has been
     added to the
     exception
    Click OK to confirm
     the exception
University of Leeds Academic Services



Finalise the rule configuration

    Give a name to the
     rule if you don’t like
     the default
    Tick ‘Turn on this
     rule’
    Click ‘Finish’ to
     complete the task
University of Leeds Academic Services



Refining rules (false positive)

   Review the Spam folder
   Find any messages falsely identified
   Find the sender’s address of such messages
   Add a new rule in front of the basic rule to allow
    this sender through
   Or, add the sender to your contact list
   Go to the top step and review again later
University of Leeds Academic Services



Refining rules (false positive)

    Add a new rule to allow
     messages from a friend
     through
    Tick the box next to the
     line ‘with specific words
     in the sender’s address’
    Click the underlined
     ‘specific words’ in the
     Rule description box
University of Leeds Academic Services



Refining rules

    Add your friends’
     email address to the
     list
    Click OK to continue
University of Leeds Academic Services



Refining rules

    You will see your
     friend’s email
     address is now in
     the rule.
    Click Next button to
     continue
University of Leeds Academic Services



Refining rules

    Tick the box next to
     the line ‘stop
     processing more
     rules’
    Press ‘Next’ button
     to continue
University of Leeds Academic Services



Refining rules

    Make sure this new
     rule is in front of the
     spam rule
    Use ‘Move Up’ or
     ‘Move Down’ button
     to reorder
University of Leeds Academic Services



Refining rules (false negative)

   Still too many spam messages in the Inbox
   Find any spam messages not identified
   Find the probability rating in the full headers
   Modify the existing rule to reduce the threshold,
    from initial 90% to 80% and then to low% (50%
    or even lower) suitable to the circumstances.
   Or, add a new rule to filer by report tags
   Review false positive and negative regularly
University of Leeds Academic Services



Summary

   Learnt what is ISS email filtering service
   Learnt the format of spam tags and where to find
    them
   Learn how to set up a basic rule with rule wizard
   Learn to set up exceptions by adding conditions
    to the basic rule or extra rules
   Learn how to refine rules by reviewing Inbox and
    Spam folders
    University of Leeds Academic Services



Further Information

    ISS Documents
      – http://www.leeds.ac.uk/iss/documentation/email.html
      – How23, How24 and How25
      – Appendix section contains report tag details
    Microsoft
      – Outlook Help, search under ‘rule’
      – Office web site, Outlook tips

				
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