Cisco Cisco Email Security Appliance C160 Mode D'Emploi

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Chapter 8      Anti-Spam
8-8
Cisco IronPort AsyncOS 7.5 for Email Configuration Guide
OL-25136-01
Analyzing multi-dimensional relationships allows CASE to catch a broad range 
of threats while maintaining exceptional accuracy. For example, a message that 
has content claiming to be from a legitimate financial institution but that is sent 
from an IP address on a consumer broadband network or that contains a URL 
hosted on a “zombie” PC will be viewed as suspicious. In contrast, a message 
coming from a pharmaceutical company with a positive reputation will not be 
tagged as spam even if the message contains words closely correlated with spam.
Industry-Leading Performance
CASE combines the following features to deliver accurate verdicts quickly:
Multiple threats are scanned for in a single pass
Dynamic “early exit” system
System performance is optimized using Cisco IronPort's unique “early exit” 
system. Cisco IronPort developed a proprietary algorithm to determine the 
order in which rules are applied based on rule accuracy and computational 
expense. Lighter and more accurate rules are run first, and if a verdict is 
reached, additional rules are not required. This improves system throughput, 
allowing our products to meet the needs of large-scale enterprises. 
Conversely, the efficiency of the engine allows for implementation on 
low-cost hardware, making Cisco IronPort’s security services attractive for 
low-end customers.
Off-box network calculations
International Users
IronPort Anti-Spam is tuned to deliver industry-leading efficacy world-wide. In 
addition to locale-specific content-aware threat detection techniques, you can 
further optimize anti-spam scanning for specific regions using regional rules 
profiles. The anti-spam engine includes a regional rules profile. The regional rules 
profile targets spam on a regional basis. For example, China and Taiwan receive 
a high percentage of spam in traditional or modern Chinese. The Chinese regional 
rules are optimized for this type of spam. Cisco strongly recommends you use the 
Chinese regional rules profile if you receive mail primarily for mainland China, 
Taiwan, and Hong Kong. You can enable the regional rules profile from Security 
Services > IronPort Anti-Spam.