User Guide

24-7
AsyncOS 9.1.2 for Cisco Email Security Appliances User Guide
Chapter 24 Configuring Routing and Delivery Features
Creating Alias Tables
Table 24-1 provides an overview of the various features used for rewriting sender and recipient email
addresses.
Creating Alias Tables
Alias tables provide a mechanism to redirect messages to one or more recipients. You can construct a
mapping table of aliases to usernames and other aliases in a similar fashion to the
/etc/mail/aliases
feature of a sendmail configuration on some Unix systems.
When the Envelope Recipient (also known as the Envelope To, or
RCPT TO) of an email accepted by a
listener matches an alias as defined in an alias table, the Envelope Recipient address of the email will be
rewritten.
Note A listener checks the alias table and modifies the recipients after checking the RAT and before message
filters. See the “Understanding the Email Pipeline” chapter.
Note The Alias Table functionality actually rewrites the Envelope Recipient of the email. This is different than
the
smtproutes command (see Directing Bounced Email, page 24-35), which does not rewrite the
Envelope Recipient of the email, but instead simply reroutes the email to specified domains.
Related Topics
• Configuring an Alias Table from the Command Line, page 24-7
• Exporting and Importing an Alias Table, page 24-8
• Deleting Entries from the Alias Table, page 24-9
Configuring an Alias Table from the Command Line
Alias tables are defined in sections as follows: each section is headed by a domain context, which is a
list of domains that the section is relevant to, followed by a list of maps.
Table 24-1 Methods for Rewriting Addresses
Original Address Change to Feature Works on
*@anydomain user@domain Alias Tables (see
Creating Alias Tables,
page 24-7)
• Envelope Recipients only
• Applied globally
• Maps aliases to email
addresses or other aliases
*@olddomain *@newdomain Domain Mapping (see
The Domain Map
Feature, page 24-28)
• Envelope Recipients only
• Applied per listener
*@olddomain *@newdomain Masquerading (see
Configuring
Masquerading,
page 24-16)
• Envelope Sender and the
To:, From:, and/or CC:
headers
• Applied per listener