Cisco Cisco Email Security Appliance C160 User Guide
9-20
Cisco IronPort AsyncOS 7.6 for Email Configuration Guide
OL-25136-01
Chapter 9 Anti-Spam
Figure 9-12
Mail Relayed by MX/MTA — Simple
shows two other, slightly more complicated examples of how mail may be relayed inside the
network and how mail may be processed by several servers within the network before it is passed to the
Cisco IronPort appliance. In example A, mail from 7.8.9.1 passes through the firewall and is processed
by an MX and an MTA before being delivered to the Cisco IronPort appliance. In example B, mail from
7.8.9.1 is sent to a load balancer or other type of traffic shaping appliance and is sent to any one of a
range of MXs prior to being delivered to the Cisco IronPort appliance.
Cisco IronPort appliance. In example A, mail from 7.8.9.1 passes through the firewall and is processed
by an MX and an MTA before being delivered to the Cisco IronPort appliance. In example B, mail from
7.8.9.1 is sent to a load balancer or other type of traffic shaping appliance and is sent to any one of a
range of MXs prior to being delivered to the Cisco IronPort appliance.
Figure 9-13
Mail Relayed by MX/MTA — Advanced
IronPort Email Security appliance
Firewall
MX / MTA
Sending
Machine
Machine
IP: 7.8.9.1
IP: 10.2.3.4
IP: 10.2.3.5
IronPort Email Security appliance
Firewall
MX
Sending
Machine
Machine
IP: 7.8.9.1
IP: 10.2.3.4
IP: 10.2.3.6
MTA
IP: 10.2.3.5
Hop 2
Hop 2
Hop 1
MX
IP: 10.2.5.1-n
MX
IP: 10.2.6.1
Mail Filter
Hop 1
A
B