Fortinet FortiGate 3000, Руководство администратора

Страница: 355 / 398

Spam filter Using Perl regular expressions
FortiGate-3000 Administration Guide 01-28006-0010-20041105
355
Word boundary
In Perl regular expressions, the pattern does not have an implicit word boundary. For
example, the regular expression “test” not only matches the word “test” but also
matches any word that contains the “test” such as “atest”, “mytest”, “testimony”,
“atestb”. The notation “\b” specifies the word boundary. To match exactly the word
“test”, the expression should be \btest\b.
Case sensitivity
Regular expression pattern matching is case sensitive in the Web and Spam filters. To
make a word or phrase case insensitive, use the regular expression
/i
For example,
/bad language/i
will block all instances of “bad language” regardless of case.
Table 35: Perl regular expression formats
Expression Matches
abc abc (that exact character sequence, but anywhere in the string)
^abc abc at the beginning of the string
abc$ abc at the end of the string
a|b either of a and b
^abc|abc$ the string abc at the beginning or at the end of the string
ab{2,4}c an a followed by two, three or four b's followed by a c
ab{2,}c an a followed by at least two b's followed by a c
ab*c an a followed by any number (zero or more) of b's followed by a c
ab+c an a followed by one or more b's followed by a c
ab?c an a followed by an optional b followed by a c; that is, either abc or ac
a.c an a followed by any single character (not newline) followed by a c
a\.c a.c exactly
[abc] any one of a, b and c
[Aa]bc either of Abc and abc
[abc]+ any (nonempty) string of a's, b's and c's (such as a, abba, acbabcacaa)
[^abc]+ any (nonempty) string which does not contain any of a, b and c (such as defg)
\
d\d
any two decimal digits, such as 42; same as \d{2}
/i makes the pattern case insensitive. For example,
/bad language/i
blocks
any instance of
bad language
regardless of case.
\
w+
a “word”: a nonempty sequence of alphanumeric characters and low lines
(underscores), such as foo and 12bar8 and foo_1
100\s*mk the strings 100 and mk optionally separated by any amount of white space
(spaces, tabs, newlines)