Cisco Cisco Email Security Appliance C160 Mode D'Emploi

After you have configured the basic settings of your Cisco IronPort appliance via the GUI’s System 
Setup Wizard (or the CLI 

systemsetup

 command), you are now ready to begin tailoring the 

configuration of your Cisco IronPort Email Security appliance to receive email. This chapter discusses, 
in detail, all of the features available to you as you begin to configure listeners on the appliance to handle 
receiving email. 

The concept of the Host Access Table (HAT) is introduced. The Host Access Tables (HATs) of public 
listeners — with their specific sender groups and mail flow policies — provide the underlying 
framework that makes possible the Mail Flow Monitor feature. (“Using Email Security Monitor” in the 
Cisco IronPort AsyncOS for Email Daily Management Guide describes the Mail Flow Monitor feature 
in detail.)

The Cisco IronPort AsyncOS operating system allows the Cisco IronPort appliance to function as the 
inbound email gateway for your enterprise, servicing SMTP connections from the Internet, accepting 
messages, and relaying messages to the appropriate systems.

In this configuration, you enable listeners to service these connections. A listener describes an email 
processing service that will be configured on a particular IP interface. Listeners only apply to email 
entering the Cisco IronPort appliance — either from the internal systems within your network or from 
the Internet. Cisco IronPort AsyncOS uses listeners to specify criteria that messages must meet in order 
to be accepted and relayed to recipient hosts. You can think of a listener as an “email injector” or even 
a “SMTP daemon” running on a specific port for each IP address you specify (including the initial 
addresses you configured with the 

systemsetup

 command).