Cisco Cisco Email Security Appliance C170 Guia Do Utilizador

you could create a list of confidential or profane words, and, using a filter rule to 
scan messages that contain words in the list, drop, archive, or quarantine the 
message.

The AsyncOS operating system includes the ability to define a total of 100 content 
dictionaries using the GUI (Mail Policies > Dictionaries) or the CLI’s 

dictionaryconfig

 command. You can create, delete, and view dictionaries; add 

and delete entries from a dictionary; and import and export entire dictionaries. 

Words in dictionaries are created with one text string per line, and entries can be 
in plain text or in the form of regular expressions. Dictionaries can also contain 
non-ASCII characters. Defining dictionaries of regular expressions can provide 
more flexibility in matching terms, but doing so requires you to understand how 
to delimit words properly. For a more detailed discussion of Python style regular 
expressions, consult the Python Regular Expression HOWTO, accessible from 

     

  http://www.python.org/doc/howto/

To use the special character # at the beginning of a dictionary entry, you can use 
a character class [#] to prevent it being treated as a comment. 

For each term, you specify a “weight,” so that certain terms can trigger filter 
conditions more easily. When AsyncOS scans messages for the content dictionary 
terms, it “scores” the message by multiplying the number of term instances by the 
weight of term. Two instances of a term with a weight of three would result in a 
score of six. AsyncOS then compares this score with a threshold value associated 
with the content or message filter to determine if the message should trigger the 
filter action. 

You can also add smart identifiers to a content dictionary. Smart identifiers are 
algorithms that search for patterns in data that correspond to common numeric 
patterns, such as social security numbers and ABA routing numbers. These 
identifiers can useful for policy enforcement. For more information about regular 
expressions, see “Regular Expressions in Rules” in the “Using Message Filters to 
Enforce Email Policies” chapter of the Cisco IronPort AsyncOS for Email 
Advanced Configuration Guide. For more information about smart identifiers, see 
“Smart Identifiers” in the “Using Message Filters to Enforce Email Policies” 
chapter of the Cisco IronPort AsyncOS for Email Advanced Configuration Guide.