User Guide

4-10

AsyncOS 9.1.2 for Cisco Email Security Appliances User Guide

Chapter 4 Understanding the Email Pipeline

Delivery

Content Filters

You can create content filters to be applied to messages on a per-recipient or per-sender basis. Content

filters are similar to message filters, except that they are applied later in the email pipeline — after a

message has been “splintered” into a number of separate messages for each matching Email Security

Manager policy. The functionality of content filters is applied after message filters processing and

anti-spam and anti-virus scanning have been performed on a message.

For more information about Content Filters, see Overview of Content Filters, page 11-1.

Outbreak Filters

Cisco’s Outbreak Filters feature includes special filters that act proactively to provide a critical first layer

of defense against new outbreaks. Based on Outbreak Rules published by Cisco, messages with

attachments of specific filetypes can be sent to a quarantine named Outbreak.

Messages in the Outbreak quarantine are processed like any other message in a quarantine. For more

information about quarantines and the Work Queue, see Quarantines, page 4-10.

See Chapter 14, “Outbreak Filters” for more information.

Quarantines

You can filter incoming or outgoing messages and place them into quarantines. Quarantines are special

queues or repositories used to hold and process messages. Messages in quarantines can be delivered or

deleted, based on how you configure the quarantine.

The following Work Queue features can send messages to quarantines:

• Spam filters

• Message Filters

• Anti-Virus

• Outbreak Filters

• Content Filters

• File Analysis (Advanced Malware Protection)

Messages delivered from quarantines are re-scanned for threats.