How Dynamic Document Review works in Symantec products

Article:TECH79958  |  Created: 2002-01-17  |  Updated: 2013-10-24  |  Article URL http://www.symantec.com/docs/TECH79958
Article Type
Technical Solution


Environment

Issue



You want a general idea of how the Dynamic Document Review (DDR) filtering system works in Symantec Web Security, Mail-Gear, I-Gear or Symantec AntiVirus/Filtering for Domino on Windows NT/2000.

 


Cause



DDR, score, dictionary


Solution



Symantec products using DDR review Web content as information is being downloaded to the user. DDR has the capability of checking for objectionable words in multiple languages that are found in headers and in content, by using multilingual filters.

To determine when to block or allow access to a site, DDR uses predefined dictionaries that contain trigger words in multiple languages. You can manually add and score words to each dictionary. Each occurrence of a word contained in an active dictionary receives a numerical score. When DDR is scanning the headers and content, it keeps a running total score for a given amount of text. When the total score meets or exceeds the threshold setting, a Deny access box appears, and access to that site is blocked. The default score that is used to deny access is 50. However, this can be changed.

A numerical score is assigned to each word or phrase in the dictionary. Words that are more objectionable should have a higher score (range is 1-250), while words that are positive, and those used to offset negative words or phrases, should have a lower or negative score (range is 0 to -25).

A simple example of how DDR works, using the words breast, sexy, and cancer: Let's say that the numerical score for breast is +25, sexy is +30 and cancer is -25. If the threshold (total numerical value) is set to 50, then a site which contained breast and sexy in the header or content would be blocked, as the combined score exceeds the threshold of 50. Alternatively, a site which contained the words breast and cancer would not be denied access.

NOTE: If some words are ignored, check to see if the words contain the characters, period, dash or exclamation that are being scanned. Try converting these characters to spaces. You should see the words picked up as expected.

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NOTE: The contents of DDR dictionaries cannot be viewed or modified.
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Legacy ID



2002051708165354


Article URL http://www.symantec.com/docs/TECH79958


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