Cisco Cisco Email Security Appliance X1050 Guía Del Usuario
18-2
Cisco AsyncOS 8.0.2 for Email User Guide
Chapter 18 Text Resources
Content Dictionaries
Message Disclaimer Stamping
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.
you could append a copyright statement, promotional message, or disclaimer to every message sent from
within your enterprise.
Content Dictionaries
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.
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
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.
Dictionary Content
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
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/
Note
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.
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.
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.
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.