Руководство Пользователя для Cisco Cisco Email Security Appliance C170
C H A P T E R
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Cisco IronPort AsyncOS 7.5 for Email Advanced Configuration Guide
OL-25137-01
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Validating Recipients Using an SMTP
Server
Server
This chapter explains how to validate recipients using an SMTP server.
This chapter contains the following sections:
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SMTP Call-Ahead Recipient Validation: Overview
SMTP call-ahead recipient validation allows you to perform recipient validation
by querying an external SMTP server prior to accepting incoming mail for the
recipient. SMTP call-ahead recipient validation is useful in cases where you
might want to validate users but cannot use LDAP Accept or the Recipient Access
Table (RAT) for recipient validation. For example, a customer hosts mail for a
large number of different mailboxes, each using a separate domain. Because of the
LDAP infrastructure, there is no way to query the infrastructure to validate each
of the customers in their separate domains. In this case, the customer could set up
by querying an external SMTP server prior to accepting incoming mail for the
recipient. SMTP call-ahead recipient validation is useful in cases where you
might want to validate users but cannot use LDAP Accept or the Recipient Access
Table (RAT) for recipient validation. For example, a customer hosts mail for a
large number of different mailboxes, each using a separate domain. Because of the
LDAP infrastructure, there is no way to query the infrastructure to validate each
of the customers in their separate domains. In this case, the customer could set up