Authentication, Authorization, and Accounting Configuration Guide, Cisco IOS Release 15M&T
RADIUS Packet of Disconnect
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RADIUS Packet of Disconnect

The RADIUS Packet of Disconnect feature is used to terminate a connected voice call.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and 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 table at the end of this module.

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.

Prerequisites for RADIUS Packet of Disconnect

  • Configure AAA as described in Cisco IOS Security Configuration Guide: Securing User Services , Release 15.0(1)M.
  • Use Cisco IOS Release 12.2(11)T or later.

Restrictions for RADIUS Packet of Disconnect

Proper matching identification information must be communicated by the following:

  • Billing server and gateway configuration
  • Gateway’s original accounting start request
  • Server’s POD request

Information About RADIUS Packet of Disconnect

The Packet of Disconnect (POD) is a RADIUS access_request packet and is intended to be used in situations where the authenticating agent server wants to disconnect the user after the session has been accepted by the RADIUS access_accept packet.

When the POD is Needed

The POD may be needed in at least two situations:

  • Detection of fraudulent use, which cannot be performed before accepting the call. A price structure so complex that the maximum session duration cannot be estimated before accepting the call. This may be the case when certain types of discounts are applied or when multiple users use the same subscription simultaneously.
  • To prevent unauthorized servers from disconnecting users, the authorizing agent that issues the POD packet must include three parameters in its packet of disconnect request. For a call to be disconnected, all parameters must match their expected values at the gateway. If the parameters do not match, the gateway discards the packet of disconnect packet and sends a NACK (negative acknowledgement message) to the agent.

POD Parameters

The POD has the following parameters:

  • An h323-conf-id vendor-specific attribute (VSA) with the same content as received from the gateway for this call.
  • An h323-call-origin VSA with the same content as received from the gateway for the leg of interest.
  • A 16-byte MD5 hash value that is carried in the authentication field of the POD request.
  • Cisco allocated POD code 50 as the new code value for the Voice POD Request in Cisco IOS Release 12.2(27)SB and 12.4(15)T. This change was made because RFC 3576 Dynamic Authorization Extensions to RADIUS recently extended RADIUS standards to officially support both a Disconnect Message (DM) and Change-of-Authorization (CoA), which is supported through the POD.

RFC 3576 specifies the following POD codes:

    • 40 - Disconnect-Request
    • 41 - Disconnect-ACK
    • 42 - Disconnect-NAK
    • 43 - CoA-Request
    • 44 - CoA-ACK
    • 45 - CoA-NAK

How to Configure the RADIUS Packet of Disconnect

Configuring the RADIUS POD

Use the following tasks to configure the RADIUS POD:

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    Router (config)# aaa pod server [port port-number] [auth-type {any| all| session-key}] server-key [encryption-type] string

    4.    Router# exit

    5.    Router# show running-configuration


DETAILED STEPS
      Command or Action Purpose
    Step 1 enable


    Example:
    Router> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.
     
    Step 2 configure terminal


    Example:
    Router# configure terminal
     

    Enters global configuration mode.

     
    Step 3 Router (config)# aaa pod server [port port-number] [auth-type {any| all| session-key}] server-key [encryption-type] string

    Example:
    Router(config)# aaa pod server server-key xyz123
     

    Enables inbound user sessions to be disconnected when specific session attributes are presented.

    • port port-number --(Optional) The network access server User Datagram Protocol (UDP) port to use for POD requests. Default value is 1700.
    • auth-type --(Optional) The type of authorization required for disconnecting sessions.
    • any--Session that matches all of the attributes sent in the POD packet is disconnected. The POD packet may contain one or more of four key attributes (user-name, framed-IP-address, session-ID, and session-key).
    • all --Only a session that matches all four key attributes is disconnected. all is the default.
    • session-key --Session with a matching session-key attribute is disconnected. All other attributes are ignored.
    • server-key --Configures the shared-secret text string.
    • encryption-type --(Optional) Single-digit number that defines whether the text immediately following is encrypted, and, if so, what type of encryption is used. Defined encryption types are 0, which means that the text immediately following is not encrypted, and 7, which means that the text is encrypted using an encryption algorithm defined by Cisco.
    • string --The shared-secret text string that is shared between the network access server and the client workstation. This shared-secret string must be the same on both systems.
     
    Step 4 Router# exit 

    Exits global configuration mode.

     
    Step 5 Router# show running-configuration

    Example:
    Router# show running-configuration


    Example:
    !


    Example:
    aaa authentication login h323 group radius


    Example:
    aaa authorization exec h323 group radius


    Example:
    aaa accounting update newinfo


    Example:
    aaa accounting connection h323 start-stop group radius


    Example:
    aaa pod server server-key cisco


    Example:
    aaa session-id common


    Example:
    !
     

    Verifies that the gateway is configured correctly in priveleged EXEC mode.

     

    Troubleshooting Tips

    Use the following tips to troubleshoot POD issues:

    • Ensure that the POD port is configured correctly in both the gateway (using aaa pod servercommand) and the radius server. Both should be the same.
    • Ensure that the shared-secret key configured in the gateway (using aaa pod servercommand) and in the AAA server are the same.
    • Turn on debug aaa pod command to see what's going on. This will let you know if the gateway receives the POD packet from the server and if so, it will display any errors encountered.

    The following example shows output from a successful POD request, when using the show debug command.

    Router# debug aaa podAAA POD packet processing debugging is on
    Router# show debugGeneral OS:
      AAA POD packet processing debugging is on
    Router#
    Apr 25 17:15:59.318:POD:172.19.139.206 request queued
    Apr 25 17:15:59.318:voice_pod_request:
    Apr 25 17:15:59.318:voip_populate_pod_attr_list:
    Apr 25 17:15:59.318:voip_pod_get_guid:
    Apr 25 17:15:59.318:voip_pod_get_vsa_attr_val:
    Apr 25 17:15:59.318:voip_pod_get_vsa_attr_val:attr_len=50
    Apr 25 17:15:59.318:voip_pod_get_vsa_attr_val:attr=h323-conf-id
    Apr 25 17:15:59.318:voip_pod_get_vsa_attr_val:attr_len=50 value_len=35
    Apr 25 17:15:59.318:voip_pod_get_guid:conf-id=FFA7785F F7F607BB
    00000000 993FB1F4 n_bytes=35
    Apr 25 17:15:59.318:voip_pod_get_guid:GUID = FFA7785F F7F607BB 00000000
    993FB1F4
    Apr 25 17:15:59.318:voip_populate_pod_attr_list:
    Apr 25 17:15:59.318:voip_pod_get_vsa_attr_val:
    Apr 25 17:15:59.318:voip_pod_get_vsa_attr_val:attr_len=23
    Apr 25 17:15:59.318:voip_pod_get_vsa_attr_val:attr=h323-originate
    Apr 25 17:15:59.318:voip_pod_get_vsa_attr_val:attr_len=23 value_len=6
    Apr 25 17:15:59.318:voip_get_call_direction:
    Apr 25 17:15:59.318:voip_get_call_direction:returning answer
    Apr 25 17:15:59.318:voip_eval_pod_attr:
    Apr 25 17:15:59.318:cc_api_trigger_disconnect:
    Apr 25 17:15:59.322:POD:Sending ACK to 172.19.139.206/1700
    Apr 25 17:15:59.322:voip_pod_clean:
    

    Additional References

    The following sections provide references related to the RADIUS Packet of Disconnect feature.

    Related Documents

    Related Topic

    Document Title

    AAA

    Cisco IOS Security Configuration Guide: Securing User Services, Release 15.0(1)M

    Security commands

    Cisco IOS Security Command Reference

    CLI Configuration

    Cisco IOS Configuration Fundamentals Configuration Guide, Release 12.4T

    Configuring AAA for voice gateways

    Configuring AAA for Cisco Voice Gateways, Release 12.4T

    Standards

    Standard

    Title

    No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

    --

    MIBs

    MIB

    MIBs Link

    No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

    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

    RFC

    Title

    RFC 2865

    Remote Authentication Dial-in User Service

    RFC 3576

    Dynamic Authorization Extensions to RADIUS

    Technical Assistance

    Description

    Link

    The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

    To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

    Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

    http:/​/​www.cisco.com/​techsupport

    Feature Information for RADIUS Packet of Disconnect

    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 Packet of Disconnect

    Feature Name

    Releases

    Feature Information

    RADIUS Packet of Disconnect

    12.2(2)XB 12.1(2)XH 12.3(11)T 12.2(27)SB 12.4(15)T

    The RADIUS Packet of Disconnect feature is used to terminate a connected voice call.

    In Cisco IOS Release12.2(2)XB, this feature was introduced on the Cisco 3600, Cisco 5350, and Cisco 5400.

    In Cisco IOS Release 12.1(2)XH and 12.1(3)T, this feature was introduced on the Cisco 5300 and Cisco 5800.

    In Cisco IOS Release 12.2(11)T, this feature was introduced on the Cisco 5400, Cisco 5850

    In Cisco IOS Release 12.2(27)SB and 12.4(15)T, Cisco allocated POD code 50 as the new code value for the voice POD request

    The following commands were introduced or modified: aaa pod server and debug aaa pod

    Glossary

    AAA --authentication, authorization, and accounting.

    NACK --negative acknowledgement message.

    POD --packet of disconnect. An access_reject packet sent from a RADIUS server to the gateway in order to disconnect a call which has been connected already. After validation of the packet, the gateway disconnects the user. The packet contains the information to disconnect the call.

    POD server--a Cisco gateway configured to accept and process POD requests from a RADIUS authentication/authorization agent.

    RADIUS --Remote Authentication Dial-In User Service. An authentication and accounting system used by many Internet service providers.

    UDP --User Datagram Protocol. Connectionless transport layer protocol in the TCP/IP protocol stack. UDP is a simple protocol that exchanges datagrams without acknowledgments or guaranteed delivery, requiring that error processing and retransmission be handled by other protocols. UDP is defined in RFC 768.

    VoIP-- voice over IP. The ability to carry normal telephony-style voice over an IP-based Internet with POTS-like functionality, reliability, and voice quality. VoIP is a blanket term that generally refers to the Cisco standards-based (for example, H.323) approach to IP voice traffic.

    VSA --vendor-specific attribute.