Cisco IOS Security Configuration Guide: Securing User Services, Release 12.4
RADIUS Packet of Disconnect
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RADIUS Packet of Disconnect

Table Of Contents

RADIUS Packet of Disconnect

Finding Feature Information

Contents

Prerequisites for RADIUS Packet of Disconnect

Restrictions for RADIUS Packet of Disconnect

Information About RADIUS Packet of Disconnect

When the POD is Needed

POD Parameters

How to Configure the RADIUS Packet of Disconnect

Configuring the RADIUS POD

Troubleshooting Tips

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Feature Information for RADIUS Packet of Disconnect

Glossary


RADIUS Packet of Disconnect


First Published: March 19, 2001
Last Updated: October 2, 2009

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 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 Packet of Disconnect" 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://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Contents

Prerequisites for RADIUS Packet of Disconnect

Restrictions for RADIUS Packet of Disconnect

Information About RADIUS Packet of Disconnect

How to Configure the RADIUS Packet of Disconnect

Additional References

Feature Information for RADIUS Packet of Disconnect

Glossary

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

Use the following section to configure the RADIUS Packet of Disconnect feature.

Configuring the RADIUS POD

Configuring the RADIUS POD

Use the following tasks to configure the RADIUS POD:

SUMMARY STEPS

1. enable

2. configure terminal

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

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
!
aaa authentication login h323 group radius
aaa authorization exec h323 group radius
aaa accounting update newinfo
aaa accounting connection h323 start-stop group 
radius
aaa pod server server-key cisco
aaa session-id common
!

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 server command) and the radius server. Both should be the same.

Ensure that the shared-secret key configured in the gateway (using aaa pod server command) 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 pod
AAA POD packet processing debugging is on
Router# show debug
General 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

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.


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.