Cisco Cisco Email Security Appliance C170 Betriebsanweisung

Rules containing an asterisk (

*

) match “zero or more 

matches of the previous directive.” In particular, the 
sequence of a period and an asterisk (

.*

) matches any 

sequence of characters (not containing a new line). 

For example, the regular expression 

^P.*Piper$ 

matches all of these strings: 

PPiper

,

 Peter Piper

,

 

P.Piper

,

 

and

 Penelope Penny Piper

. 

The backslash character escapes special characters. 
Thus the sequence

 \. 

only matches a literal period, the 

sequence

 \$

 only matches a literal dollar sign, and the 

sequence 

\^

 only matches a literal caret symbol. For 

example, the regular expression 

^ik\.ac\.uk$

 only 

matches the string 

ik.ac.uk

.

Important Note: The backslash is also a special 
escape character for the parser. As a result, if you want 
to include backslash in your regular expression, you 
must use two backslashes — so that after parsing, only 
one “real” backslash remains, which is then passed to 
the regular expression system. So, if you wanted to 
match the example domain above, you would enter 

^ik\\.ac\\.uk$

. 

The token 

(?i)

 that indicates the rest of the regular 

expression should be treated in case-insensitive mode. 
Placing this token at the beginning of a case-sensitive 
regular expression results in a completely insensitive 
match.

For example, the regular expression “

(?i)viagra

” 

matches 

Viagra

, 

vIaGrA

, and 

VIAGRA

.