User Guide

5-4
AsyncOS 9.1.2 for Cisco Email Security Appliances User Guide
Chapter 5 Configuring the Gateway to Receive Email
Working with Listeners
Figure 5-2 Public and Private Listeners on Appliance Models with More than Two Ethernet
Interfaces
Ethernet interface: Data 2
IP interface: PublicNet (e.g. 192.168.2.1)
Public Listener:
“InboundMail”
SMTP
Cisco Email
Security appliance
Private Listener:
“OutboundMail”
Groupware server / Message generation system
Note This public listener uses SMTP
protocol on Port 25 of the
PublicNet IP interface on the
Data2 Ethernet interface to
accept messages from the
Internet.
IP interface PublicNet sends
messages to destination hosts
on the Internet.
IP interface PrivateNet sends messages to
internal mail hosts.
Note This private listener uses SMTP
protocol on Port 25 of the
PrivateNet IP interface on the
Data1 Ethernet interface to
accept messages from internal
systems in the
.example.com
domain.
Ethernet interface: Data 1
IP interface: PrivateNet (e.g. 192.168.1.1)