Expressions for content filtering policy conditions

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Article ID: 179497

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Expressions for content filtering policy conditions

Table: Expression types lists the types of expressions that you can use in content filtering policy conditions.

Table: Expression types

Expression type

Description

How messages are matched

Regular expressions

Symantec Brightmail Gateway provides the templates that you can use when you create a new content filtering policy.

You can also use these templates to copy their predefined regular expressions into any of the following locations:

  • New pattern or existing pattern

  • New or existing content filtering policy condition

These templates contain the regular expressions that are applicable to the type of rule that you can create with them. For example the Canadian Social Insurance Number template contains the regular expressions that can identify Canadian Social Insurance numbers.

See Predefined regular expressions.

See Putting predefined regular expressions into content filtering policy conditions.

When matched against a message subject line, matches on a line-by-line basis.

When matched against the message body, matches against the entire body text, not on a line-by-line basis.

Perl-compatible regular expressions

You can use the regular expressions that behave like Perl regular expressions when you create conditions for a content filtering rule. To use Perl expressions, you must use either matches regular expression or does not match regular expression as a policy condition. Symantec Brightmail Gateway supports PCRE version 6.6.

See Perl-compatible regular expressions.

See Perl-compatible regular expression examples.

Note:
To use a pattern to match certain special characters (including forward slashes), you must precede each character with backslash (\).

For more information about Perl-compatible regular expressions, see: http://www.perl.com/​doc/manual/html/​pod/perlre.html.

When matched against a message header, matches on a line-by-line basis.

When matched against the message body or attachments, matches against the entire body text, not on a line-by-line basis.


Symantec Brightmail Gateway uses different analyses when it scans messages for expression matches. If you specify a condition that uses a regular expression, Symantec Brightmail Gateway performs a regular expression analysis. If you specify a condition that uses a keyword or dictionary, Symantec Brightmail Gateway performs a text search.

See Creating content filtering policies.

See Configuring content filtering policy conditions.

See Expressions for content filtering policy conditions.