Cisco Cisco Email Security Appliance C680 User Guide

You can use the Header Repeats rule with other rules using AND or OR operators. For example, you can 
whitelist a subset of messages using the following filter:

When you use a Header Repeats rule with another rule using AND or OR operators, the Header Repeats 
rule is evaluated last, and only if needed. If a Header Repeats rule is not evaluated for a given message, 

subject

 or 

mail-from

 is not counted to compare with the supplied threshold.

As Header Repeats rule is evaluated last and only if needed, the behavior of this rule may vary when 
used with other rules using an OR operator. The following sample filter uses an OR condition of Signed 
and Header Repeats rule.

In this example, if the first nine messages processed by this filter are signed messages with identical 
subject, the Header Repeats rule will not process these messages. If the tenth message is an unsigned 
message with identical subject header as the previous nine messages, the filter will not perform the 
configured action, even though the threshold has reached.

In the following example, at any given point in time, if the filter detects 

X

 or more incoming messages 

with identical subject in the last one hour, the subsequent messages with identical subject are sent to 
Policy quarantine.

In the following example, at any given point in time, if the filter detects 

X

 or more outgoing messages 

from same envelope sender in the last one hour, the subsequent messages from the same envelope sender 
are dropped and discarded. 

In the following example, at any given point in time, if the filter detects 

X

 or more incoming or outgoing 

messages with identical subject in the last one hour, the administrator is notified for every subsequent 
message with identical subject. 

 

Use URL categories to define message actions based on the category of URLs in the message. For 
important details, see 

in 

Filter syntax when using a 

url-category

 rule is: 

F1: if (recv_listener == 'Gray')  AND (header-repeats('subject', X, 'incoming') { 

drop();}

f1: if signed OR (header-repeats('subject', 10)) { drop();}

f1 : if header-repeats('subject', X, 'incoming') { quarantine('Policy');}

f2 :  if header-repeats('mail-from', X, 'outgoing') {drop();}

f3: if header-repeats('subject', X) {notify('admin@xyz.com');}