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94 Administrator’s Guide SurfControl RiskFilter - E-mail V5.2.4
P
OLICY
M
ANAGER
Global Policy
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5 Dictionary Category – the type of dictionary that you need to use is defined by the style of message
you want to filter.
6 Select the logical operator that you want to use in this expression (see Using Logical Operators on
page 94 for more details):
• <AND> multiple selections – This filter will trigger if one of the selected keywords AND another
selected keyword appear in the message. If only one of these words appears in the message the
filter will not trigger.
•<OR> multiple selections – This filter will trigger if either one of the selected keywords appears in
the message.
You can also add an <OCCUR> to the filter to specify how many times the keyword/s must appear before
the filter is triggered.
1 Click Select. Once you have entered your expression either by adding it manually or by clicking Select
from the Content Dictionaries it will appear in the Expression List section.
2 Specify whether you want the case of the words to be considered by selecting ‘Yes’ or ‘No’ in the Case
Sensitive section.
3 If you have added an <OCCUR> operator to your expression to specify how often the word must
appear in the message, you can check the Enable Level of Severity option. RiskFilter will compare
the frequency of the expression triggering in the mail header, mail body and mail attachment with the
threshold value entered in the Severity Threshold field. If the frequency is greater than this value,
RiskFilter will perform the pre-configured filter actions.
4 Click Submit to save these new settings.
Using Logical Operators
The Advanced content filter now supports three types of logical operator: <OR>, <AND> and <OCCUR>.
• <OR> – An expression with an <OR> operator checks whether either of the keywords, ‘one before’ and
‘one after’ the operator, appears. If either keyword does appear, the expression is a match.
• <AND> – An expression with an <AND> operator checks whether both of the keywords appear. If they
do, the expression is a match. If just one keyword appears, the expression is not a match.
• <OCCUR> – An expression with an <OCCUR> operator checks the frequency of the keywords in the
expression. If the number of occurrences of the keyword in the expression is equal to or greater than
the value set by Frequency, this expression will be a match. The default value for Frequency is 1.
Note: You can add multiple expressions to complete the filtering content.