Cisco Cisco Email Security Appliance C170 Guia Do Utilizador

Message disclaimer stamping allows you to add a disclaimer text resource to messages. For example, 
you could append a copyright statement, promotional message, or disclaimer to every message sent from 
within your enterprise.

Content dictionaries are groups of words or entries that work in conjunction with the Body Scanning 
feature on the appliance and are available to both content and message filters. Use the dictionaries you 
define to scan messages, message headers, and message attachments for terms included in the dictionary 
in order to take appropriate action in accordance with your corporate policies. For example, 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.