Cisco Cisco Web Security Appliance S160 Guía Del Usuario
Chapter 16 URL Filters
Regular Expressions
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Cisco IronPort AsyncOS 7.0 for Web User Guide
OL-23079-01
Understanding Unfiltered and Uncategorized Data
When viewing URL statistics on the Monitor > URL Categories page, it is
important to understand how to interpret the following data:
important to understand how to interpret the following data:
•
URL Filtering Bypassed — This data represents policy, port, and admin user
agent blocking that occurs before URL filtering.
agent blocking that occurs before URL filtering.
•
Uncategorized URL — This data represents all transactions for which the
URL filtering engine is queried, but no category is matched.
URL filtering engine is queried, but no category is matched.
Access Log File
The access log file records the URL category for each transaction in the scanning
verdict information section of each entry. For more information about the access
log, see
verdict information section of each entry. For more information about the access
log, see
. For a list of each URL category, see
.
Regular Expressions
Regular expressions are pattern matching descriptions that contain normal
printable characters and special characters that are used to match patterns in text
strings. For example, a text string such as “welcome” matches “welcome” or
“welcomemyfriend.” When a match occurs, the function returns true. If no match
occurs, the function returns false. Actions are executed only when a
pattern-matching expression is true.
printable characters and special characters that are used to match patterns in text
strings. For example, a text string such as “welcome” matches “welcome” or
“welcomemyfriend.” When a match occurs, the function returns true. If no match
occurs, the function returns false. Actions are executed only when a
pattern-matching expression is true.
The Web Security appliance uses POSIX extended regular expression syntax,
fully described by IEEE POSIX 1003.2. However, the appliance does not support
using a backward slash to escape a forward slash. If you need to use a forward
slash in a regular expression, type the forward slash without a backward slash.
fully described by IEEE POSIX 1003.2. However, the appliance does not support
using a backward slash to escape a forward slash. If you need to use a forward
slash in a regular expression, type the forward slash without a backward slash.
Note
Technically, AsyncOS for Web uses the Flex regular expression analyzer. For
more detailed information about how it reads regular expressions, see
http://flex.sourceforge.net/manual/Patterns.html.
more detailed information about how it reads regular expressions, see
http://flex.sourceforge.net/manual/Patterns.html.
You can use regular expressions in the following locations: