Cisco Cisco Email Security Appliance C160 Mode D'Emploi
10-5
Cisco AsyncOS 9.0 for Email User Guide
Chapter 10 Mail Policies
Message Splintering
•
The message for recipient
jane@newdomain.com
will receive the anti-spam, anti-virus, outbreak
filters, and content filters defined in policy #3.
•
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.
•
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
) and the recipient (
ANY
)
matches.
Message Splintering
Intelligent message splintering is the mechanism that allows for differing recipient-based content
security rules to be applied independently to message with multiple recipients.
security rules to be applied independently to message with multiple recipients.
Each recipient is evaluated for each policy in the appropriate mail policy table (Incoming or Outgoing)
in a top-down fashion.
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:
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.”
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.
splintering scenario would be one in which a single message is splintered for each message
recipient.
•
Each message splinter is then processed by anti-spam, anti-virus, Advanced Malware Protection
(incoming messages only), DLP scanning (outgoing messages only), Outbreak Filters, and content
filters independently in the email pipeline.
(incoming messages only), DLP scanning (outgoing messages only), Outbreak Filters, and content
filters independently in the email pipeline.
illustrates the point at which messages are splintered in the email pipeline.
Table 10-2
Message Splintering in the Email Pipeline