Cisco IOS Security Configuration Guide: Securing User Services, Release 12.4

RADIUS Attribute 8 (Framed-IP-Address) in Access Requests

The RADIUS Attribute 8 (Framed-IP-Address) in Access Requests feature makes it possible for a network access server (NAS) to provide the RADIUS server with a hint of the user IP address in advance of user authentication. An application can be run on the RADIUS server to use this hint and build a table (map) of user names and IP addresses. With the RADIUS server, service applications can begin preparing user login information to have available in advance of a successful user authentication with the RADIUS server.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the "Feature Information for RADIUS Attribute 8 (Framed-IP-Address) in Access Requests" section.

Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp. An account on Cisco.com is not required.

Contents

•Prerequisites for RADIUS Attribute 8 (Framed-IP-Address) in Access Requests

•Information About RADIUS Attribute 8 (Framed-IP-Address) in Access Requests

•How to Configure RADIUS Attribute 8 (Framed-IP-Address) in Access Requests

•Configuration Examples for RADIUS Attribute 8 (Framed-IP-Address) in Access Requests

•Additional References

•Feature Information for RADIUS Attribute 8 (Framed-IP-Address) in Access Requests

Prerequisites for RADIUS Attribute 8 (Framed-IP-Address) in Access Requests

Sending RADIUS attribute 8 in the RADIUS access requests assumes that the login host has been configured to request its IP address from the NAS server. It also assumes that the login host has been configured to accept an IP address from the NAS.

The NAS must be configured with a pool of network addresses on the interface supporting the login hosts.

Information About RADIUS Attribute 8 (Framed-IP-Address) in Access Requests

When a network device dials in to a NAS that is configured for RADIUS authentication, the NAS begins the process of contacting the RADIUS server in preparation for user authentication. Typically, the IP address of the dial-in host is not communicated to the RADIUS server until after successful user authentication. Communicating the device IP address to the server in the RADIUS access request allows other applications to begin to take advantage of that information.

As the NAS is setting up communication with the RADIUS server, the NAS assigns an IP address to the dial-in host from a pool of IP addresses configured at the specific interface. The NAS sends the IP address of the dial-in host to the RADIUS server as attribute 8. At that time, the NAS sends other user information, such as the user name, to the RADIUS server.

After the RADIUS server receives the user information from the NAS, it has two options:

•If the user profile on the RADIUS server already includes attribute 8, the RADIUS server can override the IP address sent by the NAS with the IP address defined as attribute 8 in the user profile. The address defined in the user profile is returned to the NAS.

•If the user profile does not include attribute 8, the RADIUS server can accept attribute 8 from the NAS, and the same address is returned to the NAS.

The address returned by the RADIUS server is saved in memory on the NAS for the life of the session. If the NAS is configured for RADIUS accounting, the accounting start packet sent to the RADIUS server includes the same IP address as in attribute 8. All subsequent accounting packets, updates (if configured), and stop packets will also include the same IP address provided in attribute 8.

How to Configure RADIUS Attribute 8 (Framed-IP-Address) in Access Requests

This section contains the following procedures:

•Configuring RADIUS Attribute 8 in Access Requests (required)

•Verifying RADIUS Attribute 8 in Access Requests

Configuring RADIUS Attribute 8 in Access Requests

To send RADIUS attribute 8 in the access request, perform the following steps:

SUMMARY STEPS

1. enable

2. configure terminal

3. radius-server attribute 8 include-in-access-req

DETAILED STEPS

Verifying RADIUS Attribute 8 in Access Requests

To verify that RADIUS attribute 8 is being sent in access requests, perform the following steps. Attribute 8 should be present in all PPP access requests.

SUMMARY STEPS

1. enable

2. more system:running-config

3. debug radius

DETAILED STEPS

Configuration Examples for RADIUS Attribute 8 (Framed-IP-Address) in Access Requests

This section provides the following configuration example:

•NAS Configuration That Sends the IP Address of the Dial-in Host to the RADIUS Server in the RADIUS Access Request

NAS Configuration That Sends the IP Address of the Dial-in Host to the RADIUS Server in the RADIUS Access Request

The following example shows a NAS configuration that sends the IP address of the dial-in host to the RADIUS server in the RADIUS access request. The NAS is configured for RADIUS authentication, authorization, and accounting (AAA). A pool of IP addresses (async1-pool) has been configured and applied at interface Async1.

aaa new-model

aaa authentication login default group radius

aaa authentication ppp default group radius

aaa authorization network default group radius 

aaa accounting network default start-stop group radius

!

ip address-pool local

!

interface Async1

 peer default ip address pool async1-pool

!

ip local pool async1-pool 209.165.200.225 209.165.200.229

!

radius-server host 172.31.71.146 auth-port 1645 acct-port 1646

radius-server retransmit 3

radius-server attribute 8 include-in-access-req

radius-server key radhost<xxx>: Example

Additional References

The following sections provide references related to the RADIUS Attribute 8 (Framed-IP-Address) in Access Requests feature.

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Feature Information for RADIUS Attribute 8 (Framed-IP-Address) in Access Requests

Table 1 lists the release history for this feature.

Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Note Table 1 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.

Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1005R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2002-2009 Cisco Systems, Inc. All rights reserved.