Cisco Cisco Email Security Appliance C160 Mode D'Emploi
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Cisco IronPort AsyncOS 7.1 for Email Configuration Guide
OL-22158-02
Chapter 8 Anti-Spam
Figure 8-13
Mail Relayed by MX/MTA — Advanced
The Incoming Relays Feature: Overview
Occasionally, administrators need to run the IronPort appliance behind the mail
exchange (MX) or mail transfer agent (MTA) at the edge of the network instead
of receiving mail directly from the Internet. Unfortunately, when using this
configuration the IronPort appliance is not receiving the mail directly from the
Internet and so it does not have access to the last connecting IP address from the
external network. Instead mail received is listed as being received from the local
MX/MTA. It is critical for successful operation of the IronPort appliance that the
connecting IP address be known so that SenderBase Reputation Service can be
used in IronPort Intelligent Multi-Scan and IronPort Anti-Spam scanning.
exchange (MX) or mail transfer agent (MTA) at the edge of the network instead
of receiving mail directly from the Internet. Unfortunately, when using this
configuration the IronPort appliance is not receiving the mail directly from the
Internet and so it does not have access to the last connecting IP address from the
external network. Instead mail received is listed as being received from the local
MX/MTA. It is critical for successful operation of the IronPort appliance that the
connecting IP address be known so that SenderBase Reputation Service can be
used in IronPort Intelligent Multi-Scan and IronPort Anti-Spam scanning.
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