RADIUS Attribute 104

The RADIUS Attribute 104 feature allows private routes (attribute 104) to be specified in a RADIUS authorization profile. The private routes affect only packets that are received on an individual interface. The routes are stored apart from the global routing table and are not injected into any routing protocols for redistribution.

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Prerequisites for RADIUS Attribute 104

  • You must be using a Cisco RADIUS server.

  • You should be familiar with configuring RADIUS.

  • You should be familiar with policy-based routing (PBR) and private routes.

  • You should be familiar with configuring access control lists (ACLs).

  • Before using the RADIUS Attribute 104 feature, you must configure RADIUS AAA authorization and RADIUS route download.

  • The following memory bytes are requireF:\tips-migration
    • One route map--50 bytes.
    • One match-set clause--600 bytes.
    • One extended ACL--366 bytes.
    • For N number of attribute 104s, the memory requirement is (600+366)*N+50=1000*N(approximate) per user.

Restrictions for RADIUS Attribute 104

  • If you already have PBR locally (statically) configured under the interface, and you specify attribute 104, the locally configured PBR will be disabled.

  • If a pseudo next-hop address is involved, there must be a route available in the routing table for the next-hop address. If a route is not available, the packet will not be policy routed.

  • Policy routing does not order the match-set clauses and relies on the first match, so you should specify the attributes in the order in which you want them to be matched.

  • Metric numbers cannot be used in the attribute.

Information About RADIUS Attribute 104

Policy-Based Routing Background

PBR provides a mechanism for the forwarding, or routing of, data packets on the basis of defined policies. The policies are not wholly dependent on the destination address but rather on other factors, such as type of service, source address, precedence, port numbers, or protocol type.

Policy-based routing is applied to incoming packets. All packets that are received on an interface that has policy-based routing enabled are considered for policy-based routing. The router passes the packets through enhanced packet filters called route maps. On the basis of the criteria that are defined in the route maps, the packets are forwarded to the appropriate next hop.

Each entry in a route map statement contains a combination of match clauses and set clauses or commands. The match clauses define the criteria for whether appropriate packets meet the particular policy (that is, whether the conditions are met). The set clauses provide instruction for how the packets should be routed after they have met the match criteria. The match clause specifies which set of filters a packet must match for the corresponding set clause to be applied.

Attribute 104 and the Policy-Based Route Map

This section discusses the attribute 104 feature and how it works with policy-based route maps.

RADIUS Attribute 104 Overview

Using the RADIUS Attribute 104 feature, you can specify private routes in your RADIUS authorization profile. The private routes you specify will affect only packets that are received on an individual interface. The routes are stored apart from the global routing table and are not injected into any routing protocols for redistribution.

Permit Route Map

Route map statements can be marked as “permit” or “deny.” If the statement is marked “permit,” the set clause is applied to the packets that match the match criteria. For attribute 104, when you are configuring the route map, you need to mark the route map as “permit,” as follows. See Related Documents for where to find information on configuring a route map.

Default Private Route

The policy routing process proceeds through the route map until a match is found. If no match is found in the route map, the global routing table is consulted. If you have specified a default route in your user profile, any further routes beyond the default route are effectively ignored.

Route Map Order

You need to specify route maps on the server in the order that you want them to be applied.

How to Apply RADIUS Attribute 104

Applying RADIUS Attribute 104 to Your User Profile

You can apply RADIUS attribute 104 to your user profile by adding the following to the RADIUS server database.

SUMMARY STEPS

    1.    Apply RADIUS attribute 104 to your user profile.


DETAILED STEPS
     Command or ActionPurpose
    Step 1 Apply RADIUS attribute 104 to your user profile.   
    Ascend-Private-Route=”dest_addr/netmask next_hop”
    The destination network address of the router is “dest_addr/netmask”, and the address of the next-hop router is “next_hop.”
     

    Examples

    The following is a sample user profile that creates three private routes that are associated with the caller: 

    username Password="ascend"; User-Service=Framed-User
   Framed-Protocol=PPP,
   Framed-Address=10.1.1.1,
   Framed-Netmask=255.0.0.0,
   Ascend-Private-Route="172.16.1.1/16 10.10.10.1"
   Ascend-Private-Route="192.168.1.1/32 10.10.10.2"
   Ascend-Private-Route="10.20.0.0/1 10.10.10.3"
   Ascend-Private-Route="10.0.0.0/0 10.10.10.4"

    Using the above profile, the private routing table for the connection contains the following routes, including a default route: 

    Destination/Mask     Gateway
172.16.1.1/16         10.10.10.1
192.168.1.1/32         10.10.10.2
10.20.20.20/1       10.10.10.3
10.0.0.0/0            10.10.10.4

    Verifying Route Maps

    You can use the following show commands to verify the route maps that have been configured.

    SUMMARY STEPS

      1.    enable

      2.    show ip policy

      3.    show route-map [map-name | dynamic [dynamic-map-name | application [application-name]] | all]


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 enable


      Example:
      Router> enable
       

      Enables privileged EXEC mode.

      • Enter your password if prompted.

       
      Step 2 show ip policy


      Example:
      Router# show ip policy
       

      Displays the route map that is used for policy routing.

       
      Step 3 show route-map [map-name | dynamic [dynamic-map-name | application [application-name]] | all]


      Example:
      Router# show route-map
       

      Displays all route maps that are configured or only the one that is specified.

       

      Troubleshooting the RADIUS Profile

      If your private route configuration is not working properly, you may want to reread the section “Policy-Based Routing Background.” This section may help you determine what is happening to the packets. In addition, the following debug commands can be used to troubleshoot your RADIUS profile.

      SUMMARY STEPS

        1.    enable

        2.    debug radius

        3.    debug aaa per-user

        4.    debug ip policy


      DETAILED STEPS
         Command or ActionPurpose
        Step 1 enable


        Example:
        Router> enable
         

        Enables privileged EXEC mode.

        • Enter your password if prompted.

         
        Step 2 debug radius


        Example:
        Router# debug radius
         

        Displays information associated with RADIUS.

         
        Step 3 debug aaa per-user


        Example:
        Router# debug aaa per-user
         

        Displays the attributes that are applied to each user as the user authenticates.

         
        Step 4 debug ip policy

        Example:
        Router# debug ip policy
         

        Displays IP routing packet activity.

         

        Configuration Examples for RADIUS Attribute 104

        Route-Map Configuration in Which Attribute 104 Has Been Applied Example

        The following output is a typical route-map configuration to which attribute 104 has been applieF:\tips-migration

        Router# show route-map dynamic
route-map AAA-01/08/04-14:13:59.542-1-AppSpec, permit, sequence 0, identifier 1639994476
  Match clauses:
    ip address (access-lists): PBR#1 PBR#2
  Set clauses:
  Policy routing matches: 0 packets, 0 bytes
route-map AAA-01/08/04-14:13:59.542-1-AppSpec, permit, sequence 1, identifier 1640264784
  Match clauses:
    ip address (access-lists): PBR#3 PBR#4
  Set clauses:
  Policy routing matches: 0 packets, 0 bytes
route-map AAA-01/08/04-14:13:59.542-1-AppSpec, permit, sequence 2, identifier 1645563704
  Match clauses:
    ip address (access-lists): PBR#5 PBR#6
    length 10 100
  Set clauses:
    ip next-hop 10.1.1.1
    ip gateway10.1.1.1
  Policy routing matches: 0 packets, 0 bytes
 Current active dynamic routemaps = 1

        Additional References

        The following sections provide references related to RADIUS NAS-IP-Address Attribute Configurability.

        Related Documents

        Related Topic

        Document Title

        Configuring AAA

        “Authentication, Authorization, and Accounting (AAA)” section of Cisco IOS Security Configuration Guide: Securing User Services

        Configuring RADIUS

        “ Configuring RADIUS ” module.

        RADIUS commands

        Cisco IOS Security Command Reference

        Standards

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        To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

        http:/​/​www.cisco.com/​go/​mibs

        RFCs

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        Link

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        Feature Information for RADIUS Attribute 104

        The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

        Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.
        Table 1 Feature Information for RADIUS Attribute 104

        Feature Name

        Releases

        Feature Information

        RADIUS Attribute 104

        Cisco IOS XE Release 3.9S

        The RADIUS Attribute 104 feature allows private routes (attribute 104) to be specified in a RADIUS authorization profile. The private routes affect only packets that are received on an individual interface. The routes are stored apart from the global routing table and are not injected into any routing protocols for redistribution.

        The following commands were introduced or modifieF:\tips-migration show ip policy, show route-map.