Cisco Cisco IOS Software Release 12.2(27)SBC

To take advantage of this performance optimization, you need to configure the authentication method 
list so that the AAA cache profile is queried first when a user attempts to authenticate to the router. See 
the “

” section for more information.

If, for whatever reason, RADIUS or TACACS+ servers are unable to provide authentication and 
authorization responses, network users and administrators can be locked out of the network. The profile 
caching feature allows usernames to be authorized without having to complete the authentication phase. 
For example, a user by the name of user100@abc.com with a password secretpassword1 could be stored 
in a profile cache using the regular expression “.*@abc.com”. Another user by the name of 
user101@abc.com with a password of secretpassword2 could also be stored using the same regular 
expression, and so on. Because the number of users in the “.*@abc.com” profile could number in the 
thousands, it is not feasible to authenticate each user with their personal password. Therefore 
authentication is disabled and each user simply accesses authorization profiles from a common Access 
Response stored in cache.

The same reasoning applies in cases where higher end security mechanisms such as Challenge 
Handshake Authentication Protocol (CHAP), Microsoft Challenge Handshake Authentication Protocol 
(MS-CHAP), or Extensible Authentication Protocol (EAP), which all use an encrypted password 
between the client and AAA offload server, are used. To allow these unique, secure username and 
password profiles to retrieve their authorization profiles, authentication is bypassed.

To take advantage of this failover capability, you need to configure the authentication and authorization 
method list so that the cache server group is queried last when a user attempts to authenticate to the 
router. See the “

” section for more 

information.

A method list is a sequential list describing the authentication methods to be queried in order to 
authenticate a user. We support methods such as local (use the local Cisco IOS database), none (do 
nothing), RADIUS server group, or TACACS+ server group. Typically, more than one method can be 
configured into a method list. Cisco IOS software uses the first listed method to authenticate users. If 
that method fails to respond, the Cisco IOS software selects the next authentication method listed in the 
method list. This process continues until there is successful communication with a listed authentication 
method, or until all methods defined in the method list are exhausted.

To optimize network performance or provide failover capability using the profile caching feature you 
simply change the order of the authentication and authorization methods in the method list. To optimize 
network performance, make sure the cache server group appears first in the method list. For failover 
capability, the cache server group should appear last in the method list.

Because the number of usernames and profiles that can request to be authenticated or authorized at a 
given router on a given point of presence (POP) can be quite extensive, it would not be feasible to cache 
all of them. Therefore, only usernames and profiles that are commonly used or that share a common 
authentication and authorization response should be configured to use caching. Commonly used 
usernames such as aolip and aolnet, which are used for America Online (AOL) calls, or preauthentication 
dialed number identification service (DNIS) numbers used to connect Public Switched Telephone