Cisco Cisco Email Security Appliance C190 User Guide

Cisco

Contents

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Cisco AsyncOS 8.0.1 for Email User Guide

Defining Rules for Incoming Messages Using a Mail Flow Policy

7-14

Defining Default Values for Mail Flow Policies

7-19

Working with the Host Access Table Configuration

7-20

Exporting the Host Access Table Configuration to an External File

7-20

Importing the Host Access Table Configuration from an External File

7-20

Using a List of Sender Addresses for Incoming Connection Rules

7-21

SenderBase Settings and Mail Flow Policies

7-21

Timeouts for SenderBase Queries

7-22

HAT Significant Bits Feature

7-22

Verifying Senders

7-26

Sender Verification: Host

7-27

Sender Verification: Envelope Sender

7-27

Implementing Sender Verification — Example Settings

7-29

Testing Your Settings for Messages from Unverified Senders

7-34

Sender Verification and Logging

7-36

Enabling Host DNS Verification via the CLI

7-36

C H A P T E R

Accepting or Rejecting Connections Based on Domain Name or Recipient Address

8-1

Overview of Accepting or Rejecting Connections Based on the Recipient’s Address

8-1

Overview of the Recipient Access Table (RAT)

8-2

Accessing the RAT

8-2

Editing the Default RAT Entry

8-2

Domains and Users

8-2

Adding Domains and Users For Which to Accept Messages

8-3

Rearranging the Order of Domains and Users in the Recipient Access Table

8-5

Exporting the Recipient Access Table to an External File

8-5

Importing the Recipient Access Table from an External File

8-6

C H A P T E R

Using Message Filters to Enforce Email Policies

9-1

9-1

Components of a Message Filter

9-2

Message Filter Rules

9-2

Message Filter Actions

9-2

Message Filter Example Syntax

9-3

Message Filter Processing

9-3

Message Filter Order

9-4

Message Header Rules and Evaluation

9-4

Message Bodies vs. Message Attachments

9-5