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User Guide for Cisco Secure ACS for Windows Server
78-14696-01, Version 3.1
Chapter 12 Administering External User Databases
Unknown User Processing
•
Selected Databases—Lists the external user databases that
Cisco Secure ACS uses to authenticate an unknown user (if the Check the
following external user databases option is selected). Cisco Secure ACS
attempts authentication using the selected databases one at a time in the order
specified. For more information about the significance of the order of selected
databases, see
Database Search Order, page 12-9
.
For more information about configuring your Unknown User Policy, see
Configuring the Unknown User Policy, page 12-9
.
Database Search Order
You can configure the order in which Cisco Secure ACS checks the selected
external databases when Cisco Secure ACS attempts to authenticate unknown
users. If the first database in the Selected Databases list fails the authentication
request for the unknown user, Cisco Secure ACS checks the next database listed,
and so on down the Selected Databases list, in the order listed, until the user
authenticates or until Cisco Secure ACS has tried all the databases listed.
Authentication with a Windows NT/2000 database is more complex. (For more
information about Windows NT/2000 authentication, see
The Cisco Secure ACS
Authentication Process with Windows NT/2000 User Databases, page 11-9
.) If
Cisco Secure ACS does not find the user in any of the listed databases,
authentication fails.
The order in which the databases appear in the Selected Databases list is
important. To determine how to order databases in the Selected Databases list,
follow these recommendations:
•
Place databases that will allow most authentications to succeed as near to the
top of the list as possible.
•
Place databases associated with particularly time-sensitive AAA clients or
authentication protocols as near to the top of the list as possible.
For example, if wireless LAN users access your network with PEAP, arrange
the databases in the Selected Databases list so that unknown user processing
takes less than the timeout value specified on the Cisco Aironet Access Point.
Configuring the Unknown User Policy
In Cisco Secure ACS, an unknown user is defined as a user for whom no account
has been created within the Cisco Secure ACS database.