Cisco Cisco Email Security Appliance X1070 Guía Del Usuario
Chapter 8 Anti-Spam
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Cisco IronPort AsyncOS 7.5 for Email Configuration Guide
OL-25136-01
Incoming Relays
The Incoming Relays feature helps your Cisco IronPort appliance obtain the IP
address of an external machine that is sending mail to the Cisco IronPort
appliance via one or more mail exchange/transfer agents (MX or MTA), filtering
servers, etc. at the edge of the network. In this type of configuration, the IP
address of the external machine is not automatically known by the Cisco IronPort
appliance. Instead, mail appears to originate from the local MX/MTA (the
incoming relay) rather than from the external machine. IronPort Anti-Spam and
IronPort Intelligent Multi-Scan depend on accurate IP addresses for external
senders so it is vital for the Cisco IronPort appliance to have this information.
address of an external machine that is sending mail to the Cisco IronPort
appliance via one or more mail exchange/transfer agents (MX or MTA), filtering
servers, etc. at the edge of the network. In this type of configuration, the IP
address of the external machine is not automatically known by the Cisco IronPort
appliance. Instead, mail appears to originate from the local MX/MTA (the
incoming relay) rather than from the external machine. IronPort Anti-Spam and
IronPort Intelligent Multi-Scan depend on accurate IP addresses for external
senders so it is vital for the Cisco IronPort appliance to have this information.
Note
You should only enable this feature if you have a local MX/MTA relaying mail to
your Cisco IronPort appliance.
your Cisco IronPort appliance.
shows a very basic example of an incoming relay. Mail from IP
address 7.8.9.1 appears to come from IP address 10.2.3.4 because the local
MX/MTA is relaying mail to the Cisco IronPort appliance.
MX/MTA is relaying mail to the Cisco IronPort appliance.
Figure 8-12
Mail Relayed by MX/MTA — Simple
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