IronPort - advanced configuration guide

Chapter 2 Configuring Routing and Delivery Features
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Figure 2-19 Four Virtual Gateway Addresses on One Ethernet Interface
IP interface: PrivateNet (e.g. 192.168.1.1)
Note that four separate IP interfaces can be used to deliver mail, where only one public listener is
configured to accept messages from the Internet.
Mapping Messages to IP Interfaces for Delivery
The altsrchost command provides the simplest and most straightforward method to segment each
Cisco IronPort appliance into multiple IP interfaces (Virtual Gateway addresses) from which to deliver
email. However, users requiring more power and flexibility in mapping messages to particular Virtual
Gateways should investigate the use of message filters. See Chapter 6, “Using Message Filters to
Enforce Email Policies” for more information.
The altsrchost command allows you to control which IP interface or interface group to use during
email delivery based on one of the following:
the sender’s IP address
the Envelope Sender address
SMTP
Public
listener:
InboundMail
IP interface:
PublicNet
192.168.2.1
SMTP SMTP SMTP
SMTP
IP interface:
PublicNet2
192.168.2.2
IP interface:
PublicNet3
192.168.2.3
Ethernet interface: Data 2
Ethernet interface: Data 1
To specify which IP interface or interface group the system will deliver email from, you create mapping
keys that pair either the sender’s IP address or the Envelope Sender address to an IP interface or interface
group (specified by interface name or group name).
Cisco IronPort AsyncOS will compare both the IP address and Envelope Sender address to the mapping
keys. If either the IP address or Envelope Sender address matches one of the keys, the corresponding IP
interface is used for the outbound delivery. If there is no match, the default outbound interface will be
used.
The system can match any of the following keys and take preference in the following order:
Sender’s IP address The IP address of the sender must match exactly.
Fully-formed Envelope
Sender
Example: 192.168.1.5
The Envelope Sender must match the entire address exactly.
Example: username@example.com
Cisco IronPort AsyncOS 7.6 for Email Advanced Configuration Guide
IP interface:
PublicNet4
192.168.2.4
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