Cisco Cisco Email Security Appliance C190 Guia Do Utilizador

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Chapter 6      Email Security Manager
6-6
Cisco IronPort AsyncOS 7.5 for Email Configuration Guide
OL-25136-01
Example 2
Sender 
joe@yahoo.com
 sends an incoming message with three recipients: 
john@example.com
jane@newdomain.com
, and 
bill@example.com
. The message 
for recipient 
jane@newdomain.com
 will receive the anti-spam, anti-virus, outbreak 
filters, and content filters defined in policy #3, while the message for recipient 
john@example.com
 will receive the settings defined in policy #5. Because the 
recipient 
bill@example.com
 does not match the engineering LDAP query, the 
message will receive the settings defined by the default policy. This example 
shows how messages with multiple recipients can incur message splintering. See 
 for more information. 
Example 3
Sender 
bill@lawfirm.com
 sends a message to recipients 
ann@example.com
 and 
larry@example.com
. The recipient 
ann@example.com
 will receive the anti-spam, 
anti-virus, outbreak filters, and content filters defined in policy #1, and the 
recipient 
larry@example.com
 will receive the anti-spam, anti-virus, outbreak 
filters, and content filters defined in policy #2, because the sender (
@lawfirm.com
appears sooner in the table than the user description that matches the recipient 
(
jim@
). 
Message Splintering
Intelligent message splintering (by matching policy) is the mechanism that allows 
for differing recipient-based policies to be applied independently to message with 
multiple recipients. 
Each recipient is evaluated for each policy in the appropriate Email Security 
Manager table (incoming or outgoing) in a top-down fashion. 
Each policy that matches a message creates a new message with those recipients. 
This process is defined as message splintering:
If some recipients match different policies, the recipients are grouped 
according to the policies they matched, the message is split into a number of 
messages equal to the number of policies that matched, and the recipients are 
set to each appropriate “splinter.”
If all recipients match the same policy, the message is not splintered. 
Conversely, a maximum splintering scenario would be one in which a single 
message is splintered for each message recipient.