Internet Engineering Task Force (IETF)--A task force, working under the auspices of the Internet Society (ISOC), consisting of more than 80 working groups. The IETF is responsible for developing Internet standards.

Network access server (NAS)--A Cisco access server or any other Cisco device that is acting as a client to the RADIUS server.

• RFC 2138, Remote Authentication Dial-In User Server (RADIUS), April 1997. C. Rigney.

• RFC 2139, RADIUS Accounting, April 1997. C. Rigney, A. Rubens, W. Simpson, and S. Willens.

No MIBs are supported by this feature.

Step 1 Use the aaa new-model global configuration command to enable AAA. RADIUS is administered through AAA so AAA must be enabled if you plan to use RADIUS, whether IETF draft-compliant or vendor-proprietary. For more information about AAA or using the aaa new-model command, refer to the "AAA Overview" chapter in the Cisco IOS Release 11.3 Security Configuration Guide.

Step 2 Use the aaa authentication global configuration command to define method lists, selecting RADIUS as the method for authentication. For more information about using the aaa authentication command, refer to the "Configuring Authentication" chapter in the Cisco IOS Release 11.3 Security Configuration Guide.

Step 3 Use the line and interface commands to select specific lines and interfaces to which the defined method lists will be applied. For more information about applying method lists to lines and interfaces, refer to the "Configuring Authentication" chapter in the Cisco IOS Release 11.3 Security Configuration Guide.

Step 4 Use the radius-server host non-standard command to enable your Cisco router, acting as a NAS, to recognize that the RADIUS security server is using a vendor-proprietary version of RADIUS. For more information, refer to the "Configuring RADIUS" chapter in the Cisco IOS Release 11.3 Security Configuration Guide.

Step 5 Use the radius-server key command to specify the shared secret text string used between your Cisco router and the RADIUS server. For more information, refer to the "Configuring RADIUS" chapter in the Cisco IOS Release 11.3 Security Configuration Guide.

The lines in this sample RADIUS AAA configuration are defined as follows:

• The aaa new-model command enables AAA network security services.

• The aaa authentication login admins local command defines another method list, "admins," for login authentication.

• The aaa authentication ppp dialins radius local command defines the authentication method list "dialins," which specifies that RADIUS authentication, then (if the RADIUS server does not respond) local authentication will be used on serial lines using PPP.

• The aaa authorization network radius local command is used to assign an address and other network parameters to the RADIUS user.

• The aaa accounting network start-stop radius command tracks PPP usage.

• The username command defines the username and password to be used for the PPP Password Authentication Protocol (PAP) caller identification.

• The radius-server configure-nas command defines that the Cisco router or access server will query the RADIUS server for static routes and IP pool definitions when the device first starts up.

• The radius-server host non-standard command defines the name of the RADIUS server host and identifies that this RADIUS host uses a vendor-proprietary version of RADIUS.

• The radius-server key command defines the shared secret text string between the network access server and the RADIUS server host.

• The interface group-async command selects and defines an asynchronous interface group.

• The group-range command defines the member asynchronous interfaces in the interface group.

• The encapsulation ppp command sets PPP as the encapsulation method used on the specified interfaces.

• The ppp authentication pap dialins command applies the "dialins" method list to the specified interfaces.

• The line command switches the configuration mode from global configuration to line configuration and identifies the specific lines being configured.

• The autoselect ppp command configures the Cisco IOS software to allow a PPP session to start up automatically on these selected lines.

• The autoselect during-login command is used to display the username and password prompt without pressing the Return key. After the user logs in, the autoselect function (in this case, PPP) begins.

• The login authentication admins command applies the "admins" method list for login authentication.

• The modem dialin command configures modems attached to the selected lines to only accept incoming calls.