User Guide

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AsyncOS 9.1.2 for Cisco Email Security Appliances User Guide
Chapter 24 Configuring Routing and Delivery Features
The Domain Map Feature
Note The processing of the domain map feature happens immediately before the RAT and right after Default
Domain is evaluated. See the “Understanding the Email Pipeline” chapter.
A common implementation of the domain map feature is to accept incoming mail for more than one
legacy domain. For example, if your company has acquired another company, you could construct a
domain map on the appliance to accept messages for the acquired domain and rewrite the Envelope
Recipients to your company’s current domain.
Note You can configure up to 20,000 separate, unique domain mappings.
In the following example, the
domainmap subcommand of the listenerconfig command is used to
create a domain map for the public listener “InboundMail.” Mail for the domain and any subdomain of
oldcompanyname.com is mapped to the domain example.com. The mapping is then printed for
confirmation. Contrast this example with the configuration of placing both domains in the listener’s
RAT: the domain map feature will actually rewrite the Envelope Recipient of
[e-mail]
to
[e-mail], whereas placing the domain oldcompanyname.com in the listener’s RAT will simply
accept the message for
[e-mail] and route it without rewriting the Envelope Recipient.
Also, contrast this example with the alias table feature. Alias tables must resolve to an explicit address;
they cannot be constructed to map “any username
@domain” to
“the same username
@newdomain.”
Table 24-4 Domain Map Table Example Syntax
Left Side Right Side Comments
[e-mail] [e-mail]
Only complete address for the
right side
user@.example.com [e-mail]
@example.com [e-mail]
or
@example.net
Complete address or
fully-qualified domain name.
@.example.com [e-mail]
or
@example.net
mail3.example.com> listenerconfig
Currently configured listeners:
1. Inboundmail (on PublicNet, 192.168.2.1) SMTP TCP Port 25 Public
2. Outboundmail (on PrivateNet, 192.168.1.1) SMTP TCP Port 25 Private
Choose the operation you want to perform: