User Guide

Contents

AsyncOS 9.1.2 for Cisco Email Security Appliances User Guide

Handling Messages from a Group of Senders in the Same Manner 7-13

Creating a Sender Group for Message Handling 7-13

Adding a Sender to an Existing Sender Group 7-14

Rearranging the Order of the Rules to Perform for Incoming Connections 7-14

Searching for Senders 7-15

Defining Rules for Incoming Messages Using a Mail Flow Policy 7-15

Defining Default Values for Mail Flow Policies 7-20

Working with the Host Access Table Configuration 7-21

Exporting the Host Access Table Configuration to an External File 7-21

Importing the Host Access Table Configuration from an External File 7-21

Using a List of Sender Addresses for Incoming Connection Rules 7-22

SenderBase Settings and Mail Flow Policies 7-23

Timeouts for SenderBase Queries 7-23

HAT Significant Bits Feature 7-24

Verifying Senders 7-28

Sender Verification: Host 7-28

Sender Verification: Envelope Sender 7-29

Implementing Sender Verification — Example Settings 7-31

Testing Your Settings for Messages from Unverified Senders 7-36

Sender Verification and Logging 7-37

Enabling Host DNS Verification via the CLI 7-38

CHAPTER

8 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 8-3

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

CHAPTER

9 Using Message Filters to Enforce Email Policies 9-1

Overview 9-1

Components of a Message Filter 9-2

Message Filter Rules 9-2

Message Filter Actions 9-2