Antispam Using Perl regular expressions
FortiGate Version 3.0 MR4 Administration Guide
01-30004-0203-20070102 395
Example regular expressions
To block any word in a phrase
/block|any|word/
To block purposely misspelled words
Spammers often insert other characters between the letters of a word to fool spam
blocking software.
/^.*v.*i.*a.*g.*r.*o.*$/i
/cr[eéèêë][\+\-
\*=<>\.\,;!\?%&§@\^°\$£€\{\}()\[\]\|\\_01]dit/i
To block common spam phrases
The following phrases are some examples of common phrases found in spam
messages.
/try it for free/i
/student loans/i
/you’re already approved/i
/special[\+\-
\*=<>\.\,;!\?%&~#§@\^°\$£€\{\}()\[\]\|\\_1]offer/i
100\s*mk The strings “100” and “mk” optionally separated by any amount of white
space (spaces, tabs, newlines)
abc\b “abc” when followed by a word boundary (for example, in “abc!” but not in
“abcd”)
perl\B “perl” when not followed by a word boundary (for example, in “perlert” but
not in “perl stuff”)
\x Tells the regular expression parser to ignore white space that is neither
preceded by a backslash character nor within a character class. Use this
to break up a regular expression into (slightly) more readable parts.
/x Used to add regular expressions within other text. If the first character in
a pattern is forward slash '/', the '/' is treated as the delimiter. The pattern
must contain a second '/'. The pattern between ‘/’ will be taken as a
regular expressions, and anything after the second ‘/’ will be parsed as a
list of regular expression options ('i', 'x', etc). An error occurs If the
second '/' is missing. In regular expressions, the leading and trailing
space is treated as part of the regular expression.
Table 42: Perl regular expression formats (Continued)
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