Cisco Access Registrar User Guide - Using Cisco Access Registrar Features [Cisco Access Registrar]

Table Of Contents

Using Cisco Access Registrar Server Features

Command Completion

Service Grouping Feature

Configuration Example - AccountingGroupService

Summary of Events

Configuration Example 2 - AuthenticationGroupService

Summary of Events

SHA-1 Support for LDAP-Based Authentication

Remote LDAP Server Password Encryption

Dynamic Password Encryption

Logs

Dynamic Attributes

Object Properties with Dynamic Support

Dynamic Attribute Format

Tunneling Support Feature

Configuration

Example

Notes

Validation

xDSL VPI/VCI Support for Cisco 6400

Using User-Name/User-Password for Each Cisco 6400 Device

Format of the New User-Name Attribute

Apply Profile in Cisco AR Database to Directory Users

User-Profile

User-Group

Example User-Profile and User-Group Attributes in Directory User Record

Directory Multi-Value Attributes Support

MultiLink-PPP (ML-PPP)

Dynamic Updates Feature

NAS Monitor

Automatic Customer Information Collection

Simultaneous Terminals for Remote Demonstration

Support for RADIUS Check Item Attributes

Configuring Check Items

Configuring User Check Items

Configuring Usergroup Check Items

User-Specific Attributes

Packet of Disconnect

Configuring Packet of Disconnect

Configuring the Client Object

Configuring a Resource Manager for POD

Proxying POD Requests from External Servers

CLI Options for POD

query-sessions

release-sessions

Configuring Change of Authorization Requests

Configuring the Client Object

Dynamic DNS

Configuring Dynamic DNS

Testing Dynamic DNS with radclient

Using Cisco Access Registrar Server Features

This chapter provides information about how to use the following Cisco AR server features:

•"Command Completion"

•"Service Grouping Feature" section

•"SHA-1 Support for LDAP-Based Authentication" section

•"Dynamic Attributes" section

•"Tunneling Support Feature" section

•"xDSL VPI/VCI Support for Cisco 6400" section

•"Apply Profile in Cisco AR Database to Directory Users" section

•"Directory Multi-Value Attributes Support" section

•"MultiLink-PPP (ML-PPP)" section

•"Dynamic Updates Feature" section

•"NAS Monitor" section

•"Automatic Customer Information Collection" section

•"Simultaneous Terminals for Remote Demonstration" section

•"Support for RADIUS Check Item Attributes" section

•"User-Specific Attributes" section

•"Packet of Disconnect" section

•"Dynamic DNS" section

Command Completion

Cisco Access Registrar's command completion feature provides online help by listing possible entries to the current command line when you press the Tab key after entering a partial command. The Cisco AR 4.0 server responds based on:

•The location of the cursor including the current directory

•Any data you have entered on the command line prior to pressing the Tab key

The command completion feature emulates the behavior of Cisco IOS and Kermit. When you press the Tab key after entering part of a command, the Cisco AR 3.5 server provides any identifiable object and property names. For example, after you first issue aregcmd and log in to Cisco AR 3.5, enter the following:

cd <Tab>
Administrators/  Radius/
Pressing the Tab key consecutively displays possible context-sensitive choices.

In the following example, after changing directory to /Radius/services/local-file an administrator wants to see the possible types of authentication services that can set.

cd /Radius/services/local-file
//localhost/Radius/Services/local-file ]
Name = local-file
Description = 
Type = file
IncomingScript~ = 
OutgoingScript~ = 
OutagePolicy~ = RejectAll
OutageScript~ = 
FilenamePrefix = accounting
MaxFileSize = "10 Megabytes"
MaxFileAge = "1 Day"
RolloverSchedule = 
set type <Tab>
eap-leap        file            local           radius-session  
eap-md5         group           odbc            rex             
eap-sim         ldap            radius          tacacs-udp 
Values can also be tab-completed. For example, if you decide to set the local-file service's type to file, you can do the following:

set type f<Tab>
and the command line completes to:

set type file

Service Grouping Feature

The Service Grouping feature enables you to specify multiple services (called subservices) to be used with authentication, authorization, or accounting requests. The general purpose is to enable multiple Remote Servers to process requests.

Perhaps the most common use of this feature will be to send accounting requests to multiple Remote Servers thus creating multiple accounting logs. Another common use might be to authenticate from more than one Remote Server where, perhaps the first attempt is rejected, other Remote Servers may be attempted and an Access-Accept obtained.

Clearly, in the accounting request example, each request must be successfully processed by each subservice in order for the originator of the accounting request to receive a response. This is known as a logical AND of each of the subservice results. In the authenticate example, the first subservice which responds with an accept is returned to the client or if all subservices respond with reject, then a reject is returned to the client. This is known as a logical OR of each of the subservice results.

A Service is specified as a Group Service by setting its type to group, specifying the ResultRule (AND or OR) and specifying one or more subservices in the GroupServices subdirectory. The subservices are called in numbered order and as such are in an indexed list similar to Remote Server specification in a radius Service. Incoming and outgoing scripts for the Group Service may be optionally specified.

A subservice is any configured non-Group Service. When a Group Service is used, each subservice is called in exactly the same manner as when used alone (such as if specified as the DefaultAuthenticationService). Incoming and Outgoing scripts are executed if configured and Outage Policies are honored.

Configuration Example - AccountingGroupService

The following example shows how to configure an accounting Group Service to deliver accounting requests to multiple Remote Servers.

Step 1 The first task is to setup the subservices which are to be part of the AccountingGroupService. Since subservices are merely configured Services which have been included in a service group, you need only define two new Services.

For this example, we will define two new radius Services called OurAccountingService and TheirAccountingService. A provider might want to maintain duplicate accounting logs in parallel with their bulk customer's accounting logs.

Step 2 Change directory to /radius/services. At the command line, enter the following:

cd /radius/services
[ //localhost/Radius/Services ]
Entries 1 to 2 from 2 total entries
Current filter: <all>
local-file/
local-users/
Step 3 At the command line, enter the following:

add OurAccountingService
add TheirAccountingService
The configuration of these Services is very similar to stand-alone Radius accounting service. Step-by-step configuration instructions are not provided, but the complete configuration is shown below:
[ //localhost/Radius/Services/OurAccountingService ]
Name = OurAccountingService
Description =
Type = radius
IncomingScript = OurAccountingInScript
OutgoingScript = OurAccountingOutScript
OutagePolicy = RejectAll
OutageScript =
MultipleServersPolicy = Failover
RemoteServers/
1. OurPrimaryServer
2. OurSecondaryServer
[ //localhost/Radius/Services/TheirAccountingService ]
Name = TheirAccountingService
Description =
Type = radius
IncomingScript = TheirAccountingInScript
OutgoingScript = TheirAccountingOutScript
OutagePolicy = RejectAll
OutageScript =
MultipleServersPolicy = Failover
RemoteServers/
1. TheirPrimaryServer
2. TheirSecondaryServer
The next step is to create the new AccountingGroupService. The purpose of this Service is to process Accounting requests through both OurAccountingService and TheirAccountingService.

Step 4 At the command line, enter the following:

add AccountingGroupService
Added AccountingGroupService
cd AccountingGroupService
[ //localhost/Radius/Services/AccountingGroupService ]
Name = AccountingGroupService
Description =
Type =
IncomingScript =
OutgoingScript =
set type group
Set Type group
Step 5 Set the ResultRule to AND to ensure that both services process the accounting request successfully.

set ResultRule AND
Set ResultRule AND
ls
[ //localhost/Radius/Services/AccountingGroupService ]
Name = AccountingGroupService
Description = 
Type = group
IncomingScript =
OutgoingScript =
ResultRule = AND
GroupServices/
set IncomingScript AcctGroupSvcInScript
set OutgoingScript AcctGroupSvcOutScript
Now we must add the Services we created OurAccountingService and TheirAccountingService as subservices of the Group Service.

Step 6 At the command line, enter the following:

cd GroupServices
[ //localhost/Radius/Services/AccountingGroupService/GroupServices ]
set 1 OurAccountingService
Set 1 OurAccountingService
Set 2 TheirAccountingService
Set 2 TheirAccountingService
ls
[ //localhost/Radius/Services/AccountingGroupService ]
Name = AccountingGroupService
Description = 
Type = group
IncomingScript = AcctGroupSvcInScript
OutgoingScript = AcctGroupSvcOutScript
ResultRule = AND
GroupServices/
1. OurAccountingService
2. TheirAccountingService
This completes the setup of the AccountingGroupService. To use this Service simply set it as the DefaultAccountingService and/or configure a policy/rule set which will select this Service. Essentially, this may be used in the same manner as any other stand-alone service.

Summary of Events

The following describes the flow of what happens when a client sends an accounting request which is processed by the AccountingGroupService:

1. ActGroupSvcInScript is executed.

2. OurAccountingService is called.

3. OurAccountingService's Incoming Script, OurAccountingInScript is called.

4. The request is sent to the Remote Server OurPrimaryServer and/or OurSecondaryServer, if necessary.

5. If a response is not received, because we used the AND ResultRule, the request failed and no response is sent to the client and the request is dropped. If a response is received, then the process continues.

6. OurAccountingService's Outgoing Script, OurAccountingOutScript is called.

7. TheirAccountingService is called.

8. TheirAccountingService's Incoming Script, TheirAccountingInScript is called.

9. The request is sent to the Remote Server TheirPrimaryServer and/or TheirSecondaryServer, if necessary.

10. If a response is not received, because we used the AND ResultRule, the request failed and no response is sent to the client and the request is dropped. If a response is received, then the process continues.

11. TheirAccountingService's Outgoing Script, TheirAccountingOutScript is called.

12. AcctGroupSvcOutScript is executed.

13. Standard processing continues.

Configuration Example 2 - AuthenticationGroupService

In this example, we will configure a Group Service for the purposes of providing alternate Remote Servers for a single authentication. Simply put, if Service A rejects the request, try Service B.

Step 1 The first task is to setup the subservices which are to be part of the AuthenticationGroupService. Since subservices are merely configured Services which have been included in a service group, we will simply define two new Services. For simplicity, we will define two new radius Services called AuthenticationServiceA and AuthenticationServiceB.

Step 2 At the command line, enter the following:

cd /radius/services
[ //localhost/Radius/Services ]

Entries 1 to 2 from 2 total entries

Current filter: <all>

local-file/

local-users/

add AuthenticationServiceA
add AuthenticationServiceB
Step 3 The configuration of these Services is very similar to stand-alone Radius authentication service. Step-by-step configuration instructions are not provided, but the complete configuration is shown below:

[ //localhost/Radius/Services/AuthenticationServiceA ]

Name = AuthentictionServiceA

Description =

Type = radius

IncomingScript = AuthAInScript

OutgoingScript = AuthAOutScript

OutagePolicy = RejectAll

OutageScript = AuthAOutageScript

MultipleServersPolicy = Failover

RemoteServers/

1. PrimaryServerA

2. SecondaryServerA

[ //localhost/Radius/Services/AuthenticationServiceB ]

Name = AuthentictionServiceB

Description =

Type = radius

IncomingScript = AuthBInScript

OutgoingScript = AuthBOutScript

OutagePolicy = RejectAll

OutageScript = AuthBOutageScript

MultipleServersPolicy = Failover

RemoteServers/

1. PrimaryServerB

2. SecondaryServerB

The next step is to create the new "AuthenticationGroupService". The purpose of this Service is to process authentication requests through both AuthenticationServiceA and AuthenticationServiceB if AuthenticationServiceA rejects the request.

Step 4 At the command line, enter the following:

add AuthenticationGroupService
Added AuthenticationGroupService

cd AuthenticationGroupService
[ //localhost/Radius/Services/AuthenticationGroupService ]

Name = AuthenticationGroupService

Description =

Type =

IncomingScript =

OutgoingScript =

set type group
Set Type group

Next set the ResultRule to OR because we want to ensure that if the first subservice rejects the request, we then try the second subservice. If the second subservice rejects the request, then the response to the client is a reject.

Step 5 At the command line, enter the following:

set ResultRule OR
Set ResultRule OR

Set IncomingScript AuthGroupSvcInScript
Set OutgoingScript AuthGroupSvcOutScript

Set IncomingScript AuthGroupSvcInScript
Set OutgoingScript AuthGroupSvcOutScript

ls
[ //localhost/Radius/Services/AuthenticationGroupService ]

Name = AuthenticationGroupService

Description =

Type = group

IncomingScript = AuthGroupSvcInScript

OutgoingScript = AuthGroupSvcOutScript

ResultRule = OR

GroupServices/

Now we must add the services we created "AuthenticationServiceA" and "AuthenticationServiceB" as subservices of the Group Service.

Step 6 At the command line, enter the following:

cd GroupServices
[ //localhost/Radius/Services/AuthenticationGroupService/GroupServices ]

set 1 AuthenticationServiceA
Set 1 AuthenticationServiceA

Set 2 AuthenticationServiceB
Set 2 AuthenticationServiceB

ls
[ //localhost/Radius/Services/AuthenticationGroupService ]

Name = AuthenticationGroupService

Description =

Type = group

IncomingScript = AuthGroupSvcInScript

OutgoingScript = AuthGroupSvcOutScript

ResultRule = OR

GroupServices/

1. AuthenticationServiceA

2. AuthenticationServiceB

This completes the setup of the AuthenticationGroupService. To use this Service simply set it as the DefaultAuthenticationService and/or configure a policy/rule set which will select this Service. Essentially, this may be used in the same manner as any other stand-alone Service.

Summary of Events

The following describes the flow of what happens when a client sends an Authentication request which is processed by the AuthenticationGroupService:

1. AuthGroupSvcInScript is executed.

2. AuthenticationServiceA is called.

3. AuthenticationServiceA's Incoming Script, AuthAInScript is called.

4. If the response is a reject or the request is dropped (due to an Outage Policy):

a. AuthenticationServiceA's Outgoing Script, AuthAOutScript is called.

b. Processing continues with the next service.

5. If the response is an Accept:

a. AuthenticationServiceA's Outgoing Script, AuthAOutScript is called.

b. Skip to step 9.

6. AuthenticationServiceB is called.

7. AuthenticationServiceB's Incoming Script, AuthBInScript is called.

8. Since this is the last subservice in our Group Service:

a. AuthenticationServiceB's Outgoing Script, AuthBOutScript is called.

b. Regardless of whether the request is Accepted or Rejected, processing will continue at step 9.

9. AuthGroupSvcOutScript is executed.

10. Standard processing continues.

SHA-1 Support for LDAP-Based Authentication

The Cisco Access Registrar server supports secure hash algorithm (SHA-1) for LDAP-based authentication. This feature enables the Cisco AR server to authenticate users whose passwords are stored in LDAP servers and hashed using the SHA-1 encoding scheme.

SHA-1 support actually adds functionality for the following three features to Cisco Access Registrar:

•Authentication of PAP access requests against an LDAP user entry that uses the SHA-algorithm to the hash password attribute

•Authentication of PAP access requests against an LDAP user entry that uses the SSHA algorithm to hash the password attribute

•Configuration of the Cisco AR server to dynamically determine how password attributes retrieved from LDAP are encrypted and process them accordingly

This enhancement is 100% backwards compatible. All previously supported values for the PasswordEncryptionStyle property are still supported and still provide the same behavior. The only noticeable change is that dynamic is now the default value for the PasswordEncryptionStyle property.

Remote LDAP Server Password Encryption

Prior to Cisco Access Registrar 1.7, the PasswordEncryptionStyle property on a Remote LDAP Server was limited to two values, none and crypt. SHA-1 supports adds three additional values for the PasswordEncryptionStyle property. Table 15-1 lists the valid values for this property and describes the corresponding behavior.

Table 15-1 Remote LDAP Server Password Encryption Style Values

PasswordEncryptionStyle

Access Registrar Behavior

none

All passwords retrieved from this LDAP server are assumed to be returned to Cisco AR as clear text. (There is no change in this functionality.)

crypt

All passwords retrieved from this LDAP server are assumed to be returned to Cisco AR as passwords encrypted using the UNIX crypt algorithm. (There is no change in this functionality.)

Passwords may be preceded by the {crypt} prefix which is stripped before comparing passwords.

SHA-1

All passwords retrieved from this LDAP server are assumed to be returned to Cisco AR as a Base64-encoded version of the user's password after it has been hashes using the SHA-1 mechanism (as defined by Netscape).

Passwords may be preceded by the {sha} prefix, which is stripped before comparing passwords.

SSHA-1

All passwords retrieved from this LDAP server are assumed to be encrypted/hashed using the SSHA mechanism (as defined by Netscape). Passwords may be preceded by the {ssha} prefix which is stripped before comparing passwords.

Note This is a Netscape/iPlanet-specific mechanism.

dynamic

The value instructs Cisco Access Registrar to choose the encryption mechanism on a case-by-case basis after it determines the presence of a known prefix, which the LDAP server prepends to the value of the password attribute.

For example, if the following was returned from an LDAP server as a password attribute:{SHA}qZk+NkcGgWq6PiVxeFDCbJzQ2J0=,
the password would be processed using the SHA-1 mechanism. This value will be the new default for the PasswordEncryptionStyle property.

Dynamic Password Encryption

When using the dynamic setting for the PasswordEncryptionStyle property on a Remote LDAP Server, the Cisco Access Registrar server looks for the prefixes listed in Table 15-2 to determine if encryption or a hash algorithm should be used during password comparison.

Note Password prefixes are not case sensitive.

Table 15-2 Remote LDAP Server Password Prefix Values

Password Prefix

Encryption/Hash Algorithm Used

none

None; when no known prefix is found, the password attribute is assumed to be in clear text.

{crypt}

UNIX crypt algorithm

{sha}

Secure Hash Algorithm, version 1 (SHA-1)

{ssha}

SSHA-1, as defined by Netscape.

The default value for the PasswordEncryptionStyle property on a Remote LDAP Server is dynamic.

Note Using the dynamic setting for the PasswordEncryptionStyle property will require a bit more processing for each password comparison. When using dynamic, the Cisco AR server must examine each password for a known prefix. This should have no visible impact on performance.

Logs

Turn on trace to level 4 to indicate (via the trace log) which password comparison method is being used.

Dynamic Attributes

Cisco Access Registrar 1.6 supports dynamic values for the configuration object properties listed below. Previous releases of Cisco Access Registrar only handles static values for all the object properties.

Dynamic attributes are similar to UNIX shell variables. With dynamic attributes, the value is evaluated at run time. All of the objects that support dynamic attributes will have validation turned off in aregcmd.

Object Properties with Dynamic Support

The following object properties support dynamic values:

Radius

DefaultAuthenticationService

DefaultAuthorizationService

DefaultAccountingService

DefaultSessionManager

IncomingScript

OutgoingScript

Note Do not use the following environment variables:
Accounting-Service for the /Radius/DefaultAccountingService, Authentication-Service for the /Radius/DefaultAuthenticationService, or Authorization-Service for the /Radius/DefaultAuthorizationService
User-Profile for the BaseProfile, User-Group for the Group, User-Authorization for the AuthorizationScript, Session-Manager for the DefaultSessionManager, or Session-Service for the DefaultSessionService.

/Radius/Clients

client1/

IncomingScript

OutgoingScript

/Radius/Userlist/Default

user1/

Group

BaseProfile

AuthenticationScript

AuthorizationScript

/Radius/UserGroup

Group1/

BaseProfile

AuthenticationScript

AuthorizationScript

/Radius/Vendor

Vendor1/

IncomingScript

OutgoingScript

/Radius/Service

Service1/

IncomingScript

OutgoingScript

OutageScript

OutagePolicy

/Radius/RemoteServers

remoteserver1/

IncomingScript

OutgoingScript

Remoteldapserver1/

Searchpath

Filter

Note To differentiate the properties that support dynamic attributes, we place a tilde (~) after each property, as in IncomingScript~. However, when the Cisco AR administrator is required to set values for those properties, continue to use the original property name, such as set IncomingScript ${e|realm}{Test}. The tilde is only for visual effect, and including the tilde will generate an error ("310 command Failed.")

Dynamic Attribute Format

The format of the dynamic attribute is:

${eqp|attribute-name}{default-name}

where e stands for environment dictionary, q stands for request dictionary and p stands for response dictionary. You can use e, q and p in any order. The attribute name is the name for the attribute from environment dictionary, request dictionary, or response dictionary.

For example,
/Radius
DefaultAuthenticationService = ${eq|realm}{local-users}
The default Authentication Service is determined at run time. Cisco Access Registrar first checks to see if there is one value of realm in the environment dictionary. If there is, it becomes the value of DefaultAuthenticationService. If there is not, check the value of realm in the request dictionary. If there is one value, it becomes the value of DefaultAuthenticationService. Otherwise, local-users is the DefaultAuthenticationService. If we don't set local-users as the default value, the DefaultAuthenticationSerice is null. The same concept applies to all other attribute properties.

The validation for the dynamic values of the object property will only validate the default value. In the above example, Cisco Access Registrar will do validation to check whether local-users is one of services defined in the service subdirectory.

Note When setting specific property values, do not use the tilde (~) in the property name. Doing so generates a 310 Command Failed error.

Tunneling Support Feature

Tunneling support is strictly based upon the IETF RFC: "RADIUS Attributes for Tunnel Protocol Support" (http://www.ietf.org/rfc/rfc2868.txt).

Table 15-3 lists the tunneling attributes supported in this Cisco Access Registrar release.

Table 15-3 Tunneling Attributes Supported by Cisco Access Registrar

Attribute Number

Attribute

64

Tunnel-Type

65

Tunnel-Medium-Type

66

Tunnel-Client-Endpoint

67

Tunnel-Server-Endpoint

69

Tunnel-Password

81

Tunnel-Private-Group-ID

82

Tunnel-Assignment-ID

83

Tunnel-Preference

90

Tunnel-Client-Auth-ID

91

Tunnel-Server-Auth-ID

The tunneling attribute has the following format:

(1 byte)

(1 byte)

(1 byte)

(variable number of bytes)

Type

Length

Tag

Value

Configuration

1. Configure the tag attributes as untagged attributes under the /Radius/Advanced/Attribute Dictionary directory (for example, Tunnel-Type).

2. Attach the "_tag" tag to these attributes when configuring the attributes under all of the other directories as tagged attributes (for example, Tunnel-Type_tag10 under the /Radius/Profiles/test directory). Without the tag number, the default value is (_tag = _tag0).

Example
/Radius/Advanced/Attribute Dictionary 
      /Tunnel-Client-ID 
            Name = Tunnel-Client-Endpoint 
            Description = 
            Attribute = 66 
            Type = STRING 
               Min = 0
               Max = 253
/Radius/Profiles/test
            Name = test 
            Description = 
            /Attributes 
                Tunnel-Client-Endpoint_tag3 = "129.56.123.1"
Notes

1. "_tag" is reserved for the tunneling attributes. No other attributes should include this suffix.

2. The tag number value can range from 0 through 31.

Validation

The Cisco Access Registrar server checks whether the tag attributes are defined under the /Radius/Advanced/Attribute Dictionary directory. The server also checks whether the tag number falls within the range (0-31).

xDSL VPI/VCI Support for Cisco 6400

To provide this support, a distinction must be made between device authentication packets and regular user authentication packets.

Using User-Name/User-Password for Each Cisco 6400 Device

This approach assumes that for every 6400 NAS, a device-name/device-password is created for each. Following are the required changes:

For each NAS in Cisco Access Registrar:
Name = test6400-1
     Description = 
     IPAddress = 209.165.200.224
     SharedSecret = secret
     Type = NAS
     Vendor = 
     IncomingScript = 
     OutgoingScript = 
     Device-Name = theDevice
     Device-Password = thePassword
When the 6400 sends out the device authentication packet, it may have different User-Name/User-Password attributes for each 6400 NAS. When Cisco Access Registrar receives the packet, it tries to obtain the Device-Name/Device-Password attributes from the NAS entry in the Cisco Access Registrar configuration database. When the User-Name/User-Password in the packet match the configured Device-Name/Device-Password attribute values, Cisco Access Registrar assumes that it must get the device. The next step is to replace the User-Name attribute with the concatenated <module>/<slot>/<port> string. From this point, the packet is treated as a regular packet.

Note A user record with the name of the concatenated string must be created.

Format of the New User-Name Attribute

After the device is identified, the User-Name attribute is replaced with the new value. This new value is the concatenation of 6400 <module>/<slot>/<port> information from the NAS-Port attribute and the packet is treated as a regular user authentication from this point on.

Note This format only supports NAS Port Format D. Refer to Cisco IOS documentation for more information about NAS port formats.

The format of the new User-Name attribute is the printf of "%s-%d-%d-%d-%d-%d" for the following values:

NAS-IP—in dot format of the NAS-Ip-Address attribute. For example, 10.10.10.10.

slot—apply mask 0xF0000000 on NAS-Port attribute and shift right 28 bits. For example, NAS-Port is 0x10000000, the slot value is 1.

module—apply mask 0x08000000 on NAS-Port attribute and shift right 27 bits. For example, NAS-Port is 0x08000000, the module value is 1.

port—apply mask 0x07000000 on NAS-Port attribute and shift right 24 bits. For example, NAS-Port is 0x06000000, the port value is 6.

VPI—apply mask 0x00FF0000 on NAS-Port attribute and shift right 16 bits. For example, NAS-Port is 0x00110000, the VPI value is 3.

VCI—apply mask 0x0000FFFF on NAS-Port attribute. For example, NAS-Port is 0x00001001, the VCI value is 9.

Apply Profile in Cisco AR Database to Directory Users

You can define the User-Profile and User-Group environment variables in the directory mapping and Cisco Access Registrar will apply the profiles defined in the Cisco Access Registrar database to each directory user having any of these two variables set.

User-Profile

This attribute is of type string with the format:

<Value1>::<Value2> ...

The User-Profile attribute is intended to hold a list of profile names. <Value1> and <Value2> represent the names of the profiles. They are separated by the "::" character, therefore, the "::" can not be part of the profile name. The order of values in the string has significance, as the profiles are evaluated from left to right. In this example, profile <Value2> is applied after profile <Value1>.

Assume the user record has a field called UserProfile that holds the name of the profile that applies to this user. This field is mapped to the environment attribute User-Profile. Following is how the mapping is done with aregcmd:
QuickExample/
     Name = QuickExample
     Description = 
     Protocol = ldap
     IPAddress = 209.165.200.224
     Port = 389
     ReactivateTimerInterval = 300000
     Timeout = 15
     HostName = QuickExample.company.com
     BindName = 
     BindPassword = 
     UseSSL = FALSE
     SearchPath = "o=Ace Industry, c=US"
     Filter = (uid=%s)
     UserPasswordAttribute = password
     LimitOutstandingRequests = FALSE
     MaxOutstandingRequests = 0
     MaxReferrals = 0
     ReferralAttribute = 
     ReferralFilter = 
     PasswordEncryptionStyle = None
     LDAPToEnvironmentMappings/
          UserProfile = User-Profile
     LDAPToRadiusMappings/
After Cisco Access Registrar authenticates the user, it checks whether User-Profile exists in the environment dictionary. If it finds User-Profile, for each value in User-Profile, Cisco Access Registrar looks up the profile object defined in the configuration database and adds all of the attributes in the profile object to the response dictionary. If any attribute is included in more than one profile, the newly applied profile overrides the attribute in the previous profile.

User-Group

You can use the User-Group environment variable to apply the user profile as well. In Cisco Access Registrar, a user can belong to a user group, and that user group can have a pointer to a user profile. When Cisco Access Registrar finds that a packet has User-Group set, it obtains the value of the User-Profile within the user group, and if the User-Profile exists, it applies the attributes defined in the user profile to that user.

Note that in Cisco Access Registrar, every user can also directly have a pointer to a user profile. Cisco Access Registrar applies profiles is in the following order:

1. If the user profile defined in the user group exists, apply it.

2. If the user profile defined in the user record exists, apply it.

The profile in User-Group is more generic than in User-Profile. Therefore, Cisco Access Registrar applies the profile from generic to more specific.

Example User-Profile and User-Group Attributes in Directory User Record

You can use an existing user attribute in the user record to store profile info. When this is a new attribute, we suggest you create a new auxiliary class AR_UserRecord for whichever user class is used. AR_User_Profile and AR_User_Group are two optional members in this class. They are of type string. The mapping is as follows:
LDAPToEnvironmentMappings/
      AR_User_Profile = User-Profile
      AR_User_Group = User-Group
Directory Multi-Value Attributes Support

If any attributes mapped from the LDAP directory to the Cisco Access Registrar response dictionary are multi-valued, the attributes are mapped to multiple RADIUS attributes in the packet.

MultiLink-PPP (ML-PPP)

Cisco Access Registrar supports MultiLink-PPP (ML-PPP). ML-PPP is an IETF standard, specified by RFC 1717. It describes a Layer 2 software implementation that opens multiple, simultaneous channels between systems, providing additional bandwidth-on-demand, for additional cost. The ML-PPP standard describes how to split, recombine, and sequence datagrams across multiple B channels to create a single logical connection. The multiple channels are the ports being used by the Network Access Server (NAS).

During the AA process, Cisco Access Registrar authenticates the user connection for each of its channels, even though they belong to the same logical connection. The Authentication process treats the multilink connection as if it is multiple, single link connections. For each connection, Cisco Access Registrar creates a session dedicated for management purposes. The session stays active until you logout, which subsequently frees up all of the ports in the NAS assigned to each individual session, or until the traffic is lower than a certain threshold so that the secondary B channels are destroyed thereafter. Cisco Access Registrar has the responsibility of maintaining the active session list and discards any session that is no longer valid in the system, by using the accounting stop packet issued from NAS. The multiple sessions that were established for a single logical connection must be destroyed upon the user logging out.

In addition, the accounting information that was gathered for the sessions must be aggregated for the corresponding logical connection by the accounting software. Cisco Access Registrar is only responsible for logging the accounting start and accounting stop times for each session. As those sessions belong to the same bundle, IETF provides two standard RADIUS attributes to identify the related multilink sessions. The attributes are Acct-Multi-Session-Id (attribute 50) and Acct-Link-Count (attribute 51), where Acct-Multi-Session-Id is a unique Accounting identifier used to link multiple related sessions in a log file, and Acct-Link-Count provides the number of links known to have existed in a given multilink session at the time the Accounting record was generated. The Accounting software is responsible for calculating the amount of the secondary B channel's connection time.

The secondary B channel can go up and down frequently, based upon traffic. The Ascend NAS supports the Target-Util attribute, which sets up the threshold for the secondary channel. When the traffic is above that threshold the secondary channel is up, and when the traffic is below that threshold, the secondary B channel is brought down by issuing an Accounting stop packet to Cisco Access Registrar. On the other hand, if you bring down the primary channel (that is, log out), the secondary B channel is also destroyed by issuing another Accounting stop packet to Cisco Access Registrar.

Table 15-4 lists ML-PPP related attributes.

Table 15-4 ML-PPP Attributes

Number

Attribute

Cisco NAS (IOS 11.3 Release)

Ascend NAS

44

Acct-Session-Id

Supported

Supported

50

Acct-Multi-Session-Id

Supported

Supported

51

Acct-Link-Count

Supported

Supported

62

Port-Limit

Supported

Supported

234

Target-Util

Not Supported

Supported

235

Maximum-Channels

Supported

Supported

Following are sample configurations for ML-PPP:
/Radius
     /Profile
          /Default-ISDN-Users
               Name = Default-ISDN-Users
               Description =
               Attributes/
                    Port-Limit = 2
                    Target-Util = 70
                    Session-Timeout = 70
/Radius
     /UserGroups
          /ISDN-Users
               Name = ISDN-Users
               Description = " Users who always use ISDN"
               BaseProfile = Default-ISDN-Users
               Authentication-Script = 
               Authorization-Script =
The Port-Limit attribute controls the number of concurrent sessions a user can have. The Target-Util attribute controls the threshold level at which the second B channel should be brought up.

Dynamic Updates Feature

The Dynamic Updates feature enables changes to server configurations made using aregcmd to take effect in the Cisco Access Registrar server after issuing the save command, eliminating the need for a server reload after making changes.

Table 15-5 lists the Radius object and its child objects. For each object listed, the Add and Modify or Delete columns indicate whether a dynamic update occurs after adding, modifying, or deleting an object or attribute. Entries in the Add and Modify or Delete columns also apply to child objects and child attributes of the objects listed, unless the child object is explicitly listed below the object, such as /Radius/Advanced/Ports or /Radius/Advanced/Interfaces.

Table 15-5 Dynamic Updates Effect on Radius Server Objects

Object

Add

Modify or Delete

Radius

Yes

Yes

UserLists

Yes

Yes

UserGroups

Yes

Yes

Policies

Yes

Yes

Clients

Yes

Yes

Vendors

Yes

Yes

Scripts

Yes

Yes

Services

Yes

Yes

SessionManagers

Yes

No

ResourceManagers

Yes

No

Profiles

Yes

Yes

Rules

Yes

Yes

Translations

Yes

Yes

TranslationGroups

Yes

Yes

RemoteServers

Yes

No

Replication

No

No

Advanced

Yes

Yes

SNMP

No

No

Ports

No

No

Interfaces

No

No

The Dynamic Updates feature is subject to the following limitations:

•Changes to the Ports or Interfaces objects are not dynamically updated. An aregcmd reload command must be issued for these changes to be propagated to the Cisco Access Registrar server.

•Changes (modifications and deletions) to existing Session Manager and Resource Manager objects are not dynamically updated. An aregcmd reload command must be issued for these changes to be propagated to the Cisco Access Registrar server. However, additions of new Session Manager and Resource Manager objects are dynamically updated. Active sessions and allocated resources are preserved in this case.

•Changes to the Cisco Access Registrar configuration may not be immediately propagated to the server. Dynamic updates are only carried out in a safe environment (that is, when packets are not being processed and when packet processing can be delayed until the changes can be made on the server safely). Dynamic updates will yield to packet processing when appropriate, thus not significantly impacting server performance.

•Changes to SNMP require the Cisco Access Registrar server to be restarted
(/etc/init.d/arservagt restart)

NAS Monitor

The ability to monitor when a NAS is down (really only unreachable from AR) is provided by nasmonitor. This program will repeatedly query a TCP port at the specified IP address until the device (NAS) is reachable. If the NAS is not reachable after a period of time, a warning E-mail is sent; if the NAS is still not reachable after another period of time, a message is sent to Cisco AR to release all sessions associated with that NAS. The port to query, the query frequency, the first time interval, the back-off time interval, and the E-mail address to send to are all configurable (with defaults); the only required parameter is the NAS IP address. This program will work for any device that has a TCP port open; it can either be run by hand, when desired, or put in a cron job. See nasmonitor -h for details.

Note You must have tclsh installed in /usr/local/bin to use nasmonitor. tclsh is part of the standard Tcl installation that can be downloaded from http://www.scriptics.com.

Automatic Customer Information Collection

The program arbug can be used to collect information about the Cisco AR server from a customer. There are several levels of detail that can be specified, from level 1 being the least to level 3 being the most. The results are collected into a tarball that can be E-mailed or ftped to Cisco as requested. See arbug -h for details.

Simultaneous Terminals for Remote Demonstration

Multiple people can view and interact in a single demonstration by using the share-access program, a standard GNU release with a special configuration for use with Cisco AR. To run screen, a technical support specialist (CSE or DE) will telnet to your server and log in as cisco. While you run /opt/CSCOar/bin/share-access (assuming /opt/CSCOar is the Cisco AR path) as root, the CSE or DE runs /opt/CSCOar/bin/share-access -r root. Now both people (or more) can see what the other types, as well as the results of the commands entered. The special Cisco AR configuration only allows root and cisco to run screen. To end a share-access session, type Control-D.

Support for RADIUS Check Item Attributes

Cisco Access Registrar supports RADIUS check item attributes configuration at the user and group levels. You can configure the Cisco AR server to check for attributes that must be present or attributes that must not be present in the Access-Request packet for successful authentication.

When using check item attributes, the Cisco AR server will reject Access-Requests if:

•Any of the configured check item attributes are not present in the Access-Request packet

•Any of the Access-Request packet's check item attribute values do not match with those configured check item attribute values

For remote servers using either LDAP or ODBC, Cisco AR allows for mapping of certain LDAP or ODBC fields to check item attributes. The mapped attributes can be used as check item attributes while processing the Access-Request packets.

When you configure check item attributes at both the user and group levels, the Cisco AR 4.0 server first checks the attributes of the user level before those of the group level. The Cisco AR 4.0 server must first authenticate the user's password in the Access-Request before validating the check item attributes.

The Cisco AR 4.0 server logs details about any rejected Access-Requests as a result of check items processing.

Configuring Check Items

You use aregcmd to configure check item attributes.

Configuring User Check Items

The follow example shows how to configure UserList check item attributes.

Step 1 Log in to the Cisco AR 4.0 server, and use aregcmd to navigate to //localhost/Radius/UserLists/default/bob.
[ //localhost/Radius/UserLists/Default/bob ]
Name = bob
Description = 
Password = <encrypted>
AllowNullPassword = FALSE
Enabled = TRUE
Group~ = PPP-users
BaseProfile~ = 
AuthenticationScript~ = 
AuthorizationScript~ = 
UserDefined1 = 
Attributes/
CheckItems/
Step 2 Change directory to CheckItems.

cd CheckItems
[ //localhost/Radius/UserLists/Default/bob/CheckItems ]
Step 3 Use set to add any attributes to be used as check items.

set calling-Station-Id 4085551212
save

Configuring Usergroup Check Items

The follow example shows how to configure UserGroups check item attributes.

Step 1 Log in to the Cisco AR 4.0 server, and use aregcmd to navigate to //localhost/Radius/UserGroups/Default.

cd /Radius/UserGroups/Default
[ //localhost/Radius/UserGroups/Default ]
Name = Default
Description = "Users who sometimes connect using PPP and sometimes connect "
BaseProfile~ = 
AuthenticationScript~ = 
AuthorizationScript~ = AuthorizeService
Attributes/
CheckItems/
Step 2 Change directory to CheckItems.

cd CheckItems
[ //localhost/Radius/UserGroups/Default/CheckItems ]
Step 3 Use set to add any attributes to be used as check items.

set NAS-IP-Address 10.10.10.10
save

User-Specific Attributes

The Cisco AR 4.0 server supports user-specific attributes which enables the Cisco AR server to return attributes on a per-user or per-group basis without having to use profiles.

The Cisco AR 4.0 server includes a property called HiddenAttributes to the User and UserGroup object. The HiddenAttributes property contains a concatenation of all user-level reply attributes. The HiddenAttributes property is not displayed, nor can the value be set or unset using the command-line interface.

The order of application of attributes is as follows:

1. UserGroup Base Profile

2. UserGroup Attributes

3. User Base Profile

4. User Attributes

The value of the HiddenAttributes property is used dynamically to construct and populate a virtual attributes directory in the User object. All values from the Attributes directory will go into the HiddenAttributes property. This occurs transparently when the administrator issues a save command.

Packet of Disconnect

Cisco Access Registrar 4.0 supports the Packet of Disconnect (POD) feature that enables the Cisco AR server to send disconnect requests (PODs) to a NAS so that all the session information and the resources associated with the user sessions can be released. Cisco AR can also determine when to trigger and send the POD.

For example, when a PDSN handoff occurs during a mobile session, the new PDSN sends out a new access-request packet to Cisco AR for the same user. Cisco AR should detect this handoff by the change in NAS-Identifier in the new request and trigger sending a POD to the old PDSN if it supports POD. Cisco AR also provides an option for administrator to initiate sending POD requests through the command-line interface (CLI) for any user session. Cisco AR forwards POD requests from external servers to the destination NAS.

Configuring Packet of Disconnect

This section describes how to configure the Packet of Disconnect feature.

Note Some of the properties used to configure POD in earlier releases of Cisco AR have been renamed in Cisco AR 4.0.

Configuring the Client Object

You should enable POD for each client object that might want to send disconnect requests to those clients. You enable POD in a client object using the EnableDynamicAuthorization property. This property is set to FALSE by default when you create a client object. The following example shows the default configuration for a new client object, NAS1.
[ //localhost/Radius/Clients/NAS1 ]
Name = nas1
Description = 
IPAddress = 
SharedSecret = 
Type = NAS
Vendor = 
IncomingScript~ = 
OutgoingScript~ = 
EnableDynamicAuthorization = FALSE
If the Cisco AR server might send a POD to this client, set the EnableDynamicAuthorization property to TRUE. When you set this property to TRUE, the Cisco AR server creates a DynamicAuthorizationServer subdirectory under the client object. The following example shows a newly created DynamicAuthorizationServer subdirectory:
[ //localhost/Radius/Clients/NAS1/DyanamicAuthorizationServer ]
Port = 3799
DynamicAuthSharedSecret = 
InitialTimeout = 5000
MaxTries = 3
PODAttributeGroup = 
COAAttributeGroup =
The default port is 3799. You can change the port, if desired.

The property DynamicAuthSharedSecret is initially set to the same as value as the client's SharedSecret property when you set EnableDynamicAuthorization to TRUE. You can chose to configure a different secret for POD in this subdirectory.

The InitialTimeout property represents the number of milliseconds used as a timeout for the first attempt to send a POD packet to a remote server. For each successive retry on the same packet, the previous timeout value used is doubled. You must specify a number greater than zero, and the default value is 5000 (or 5 seconds).

The MaxTries property represents the number of times to send a proxy request to a remote server before deciding the server is off-line. You must specify a number greater than zero, and the default is 3.

The PODAttributeGroup property points to a group of attributes to be included in a disconnect-request packet sent to this client.

You can create and configure the PODAttributeGroup in the /Radius/Advanced/AttributeGroups/ directory. The default group contains commonly used POD attributes NAS-Port and Acct-Session-Id.

The COAAttributeGroup property is used with the Change of Authorization (CoA) feature, also knows as hot-lining.

Configuring a Resource Manager for POD

Cisco Access Registrar 4.0 adds a new resource manager type called session-cache. When you set a resource manager to session-cache, the resource manager's configuration contains a subdirectory called AttributesToBeCached. The following is an example Resource Manager set to type session-cache:
[ //localhost/Radius/ResourceManagers/PODresourceMgr ]
Name = PODresourceMgr
Description = 
Type = session-cache
OverwriteAttributes = FALSE
AttributesToBeCached/
QueryMappings/
The attributes you configure under the AttributesToBeCached directory are cached in the session record during session management. The cached attributes are then sent in the disconnect-request for this session.

The OverwriteAttributes property indicates whether to overwrite the existing attributes if there are any in the session record. Since this resource manager can be invoked during Access-Request as well as Accounting-Start processing, the OverwriteAttributes can be used to control if the attributes cached during Access-Request processing can be overwritten with the attributes available during Accounting-Start processing.

The following is an example of a typical session-cache resource manager:
[ //localhost/Radius/ResourceManagers/RM-New ] 
Name = RM-New 
Description = 
Type = session-cache 
OverwriteAttributes = TRUE 
AttributesToBeCached/ 
1. Framed-IP-Address 
2. CDMA-Correlation-ID 
QueryMappings/
The attributes used in the example can be added as an indexed list using add or set commands (in any order).

Proxying POD Requests from External Servers

Cisco AR can also proxy the disconnect requests received from external servers. To make Cisco AR listen for external POD requests, the ListenForDynamicAuthorizationRequests property under /Radius/Advanced should be set to TRUE. The default value for this is FALSE. The default POD listening port is 3799. However this can be changed by configuring a new port of type pod under /Radius/Advanced/Ports and setting the new port number accordingly.

For security reasons, the source of a POD request should be configured as a remote server in Cisco AR and the remote server should be configured to accept PODs. Set the property AcceptDynamicAuthorizationRequests to TRUE to do this. The default for this is FALSE. POD requests from unauthorized sources are silently discarded.

CLI Options for POD

Cisco Access Registrar 4.0 provides options for the query-sessions and release-sessions CLI commands that enable querying or releasing sessions based on the session's age. Another option enables querying or releasing sessions based on any valid RADIUS attribute available in the user's session record.

query-sessions

The syntax for using query-sessions with-Age option is the following:

query-sessions <path> with-Age <value>
Where <path> is the path to the server, session-manager or resource manager and <value> is the minimum age of the session specified in minutes or hours with options M, Minutes, H or Hours. This command returns all sessions that are older than the given age value.

The syntax for using query-sessions with-Attribute option is the following:

query-sessions <path> with-Attribute <name> <value>
Where <name> is the RADIUS attribute name and <value> is the value of the attribute to be matched. This command returns the sessions where a session record contains and matches the attribute value specified in <value> field.

release-sessions

The syntax for using release-sessions with-Age option is the following:

release-sessions <path> with-Age <value>
Where <path> is the path to the server, session-manager or resource manager and <value> is the minimum age of the session specified in minutes or hours with options M, Minutes, H or Hours. This command returns all sessions that are older than the given age value.

The syntax for using release-sessions with-Attribute option is the following:

release-sessions <path> with-Attribute <name> <value>
Where <name> is the RADIUS attribute name and <value> is the value of the attribute to be matched. This command returns the sessions where a session record contains and matches the attribute value specified in <value> field.

A new option is also available for release-sessions command to enable an administrator to trigger sending a POD for a user after the session is released.

release-sessions <path> with-<type> <value> [send-pod]
Where <path> is the path to the server, Session Manager, or Resource Manager and with-<type> is one of the following: with-NAS, with-User, with-IP-Address with-ID, or with-Age. The release-sessions command with an optional [send-pod] at the end results in Cisco AR sending a POD to the NAS (as determined from the session record) after the session is actually released.

Configuring Change of Authorization Requests

Cisco AR 4.0 supports Change of Authorization (CoA) requests as defined in Internet RFC 3576 that provides a way to change authorization status of users already logged on to the network. The CoA feature, also known as hot-lining, provides a wireless operator the ability to efficiently address issues with users that might otherwise be unauthorized to access packet data services. When a problem occurs that causes a user to be unauthorized to use the packet data service, a wireless operator can use the CoA feature to resolve the problem and return the user's packet data services.

When a user is hot-lined, their packet data service is redirected to a to a hot-line application that notifies the user of issues that might be blocking their access to normal packet data services. Hot-lining provides users with a way to address the issues blocking their access, such as billing issues, a prepaid account that has been depleted, or an expired credit card.

The CoA feature provides an option to the wireless operator administrator to send CoA packets to the client device when a user needs to be hot-lined. When to send a CoA request to a user depends on the wireless operator's site-specific policies.

Configuring the Client Object

You should enable CoA for each client object that might want to send CoA requests to those clients. You enable CoA in a client object using the EnableDynamicAuthorization property. This property is set to FALSE by default when you create a client object. The following example shows the default configuration for a new client object, NAS1.
[ //localhost/Radius/Clients/NAS1 ]
Name = nas1
Description = 
IPAddress = 
SharedSecret = 
Type = NAS
Vendor = 
IncomingScript~ = 
OutgoingScript~ = 
EnableDynamicAuthorization = FALSE
If the Cisco AR server might send a CoA request to this client, set the EnableDynamicAuthorization property to TRUE. When you set this property to TRUE, the Cisco AR server creates a DynamicAuthorizationServer subdirectory under the client object. The following example shows a newly created DynamicAuthorizationServer subdirectory:
[ //localhost/Radius/Clients/NAS1/COA ]
Port = 3799
DynamicAuthSharedSecret = 
InitialTimeout = 5000
MaxTries = 3
PODAttributeGroup = 
COAAttributeGroup =
The default port is 3799. You can change the port, if desired.

The property DynamicAuthSharedSecret is initially set to the same as value as the client's SharedSecret property when you set EnableDynamicAuthorization to TRUE. You can chose to configure a different secret for CoA in this subdirectory.

The InitialTimeout property represents the number of milliseconds used as a timeout for the first attempt to send a CoA packet to a remote server. For each successive retry on the same packet, the previous timeout value used is doubled. You must specify a number greater than zero, and the default value is 5000 (or 5 seconds).

The MaxTries property represents the number of times to send a proxy request to a remote server before deciding the server is off-line. You must specify a number greater than zero, and the default is 3.

The COAAttributeGroup property points to a group of attributes to be included in a CoA request packet sent to this client.

You can create and configure the COAAttributeGroup in the /Radius/Advanced/AttributeGroups/ directory. The default group is not set to any value by default. When an attribute group is configured, the Cisco AR server includes the attributes in this group in a CoA request. The values for these attributes are fetched from the user's session record.

The CoA attribute group configuration can be used with a session-cache Resource Manager. For example, any new attributes that are to be sent in a CoA request can be configured for caching by the session-cache Resource Manager so they will be available in the session record when it is to be sent in the CoA request.

The CoA request might also contain AV pairs from the optional profile name in the query-session CLI command used to send the CoA request. In a 3GPP2 scenario, a profile containing the Filter-Id attribute set to a value "Hot-Line Active" can be included when a user is to be hot-lined. This can be used as a hot-line profile possibly containing other attributes as desired by the wireless operator. Another profile might be defined containing the Filter-Id attribute with the value "Hot-Line Normal." This profile can be used with the query-session CLI command to bring the user back to normal.

The CoA request packet sent by the Cisco AR server conforms to internet RFC 3756. In response to a CoA request initiated by the Cisco AR server, the client should respond with a COA-ACK if it is able to hot-line the user based on credentials available in the CoA request. If the client is unable to hot-line the user for any reason, the client can include an error-cause attribute with the appropriate reason in a COA-NAK packet.

The Cisco AR server logs all CoA responses. If the Cisco AR server does not receive a response to a CoA request within the timeout period, it will retransmit for the configured number of retries, then logs an error if no response is received.

The Cisco AR server forwards proxied CoA requests sent by external servers to the destination NAS. The CoA requests are proxied based on the NAS-IP-Address in the incoming request. The proxied CoA requests from external servers ar forwarded to the destination NAS only if the source IP address is configured to accept dynamic authorization requests. The responses received from the NAS (either COA-ACK or COA-NAK) are forwarded back to the source where the Cisco AR server received the original proxy request.

Dynamic DNS

Cisco Access Registrar 4.0 supports the Dynamic DNS protocol providing the ability to update DNS servers. The dynamic DNS updates contain the hostname/IP Address mapping for sessions managed by Cisco AR.

You enable dynamic DNS updates by creating and configuring new Resource Managers and new Remote Servers, both of type dynamic-dns. The dynamic-dns Resource Managers specify which zones to use for the forward and reverse zones and which Remote Servers to use for those zones. The dynamic-dns Remote Servers specify how to access the DNS Servers.

Configuring Dynamic DNS

Before you configure Cisco AR you need to gather information about your DNS environment. For a given Resource Manager you must decide which forward zone you will be updating for sessions the resource manager will manage. Given that forward zone, you must determine the IP address of the primary DNS server for that zone. If the dynamic DNS updates will be protected with TSIG keys, you must find out the name and the base64 encoded value of the secret for the TSIG key. If the resource manager should also update the reverse zone (ip address to host mapping) for sessions, you will also need to determine the same information about the primary DNS server for the reverse zone (IP address and TSIG key).

If using TSIG keys, use aregcmd to create and configure the keys. You should set the key in the Remote Server or the Resource Manager, but not both. Set the key on the Remote Server if you want to use the same key for all of the zones accessed through that Remote Server. Otherwise, set the key on the Resource Manager. That key will be used only for the zone specified in the Resource Manager.

Step 1 Launch aregcmd.

Step 2 Create the dynamic-dns TSIG Keys:

cd /Radius/Advanced/DDNS/TSIGKeys
add foo.com
This example named the TSIG Key, foo.com, which is related to name of the example DNS server we use. You should choose a name for TSIG keys that reflects the DDNS client-server pair (for example, foo.bar if the client is foo and the server is bar), but you should use the name of the TSIG Key as defined in the DNS server.

Step 3 Configure the TSIG Key:

cd foo.com
set Secret <base64-encoded string>
The Secret should be set to the same base64-encoded string as defined in the DNS server. If there is a second TSIG Key for the primary server of the reverse zone, follow these steps to add it, too.

Step 4 Use aregcmd to create and configure one or more dynamic-dns Remote Servers.

Step 5 Create the dynamic-dns remote server for the forward zone:

cd /Radius/RemoteServers
add ddns
This example named the remote server ddns which is the related to the remote server type. You can use any valid name for your remote server.

Step 6 Configure the dynamic-dns remote server:

cd ddns
set Protocol dynamic-dns
set IPAddress 10.10.10.1 (ip address of primary dns server for zone)
set ForwardZoneTSIGKey foo.com
set ReverseZoneTSIGKey foo.com
If the reverse zone will be updated and if the primary server for the reverse zone is different than the primary server for the forward zone, you will need to add another Remote Server. Follow the previous two steps to do so. Note that the IP Address and the TSIG Key will be different.

You can now use aregcmd to create and configure a resource manager of type dynamic-dns.

Step 7 Create the dynamic-dns resource manager:

cd /Radius/ResourceManagers
add ddns
This example named the service ddns which is the related to the resource manager type but you can use any valid name for your resource manager.

Step 8 Configure the dynamic-dns resource manager.

cd ddns
set Type dynamic-dns
set ForwardZone foo.com
set ForwardZoneServer DDNS
Finally, reference the new resource manager from a session manager. Assuming that the example configuration was installed, the following step will accomplish this. If you have a different session manager defined you can add it there if that is appropriate.

Step 9 Reference the resource manager from a session manager:

cd /Radius/SessionManagers/session-mgr-1/ResourceManagers
set 5 DDNS

Note The Property AllowAccountingStartToCreateSession must be set to TRUE for dynamic DNS to work.

Step 10 Save the changes you have made.

Testing Dynamic DNS with radclient

After the Resource Manager has been defined it must be referenced from the appropriate Session Manager. You can use radclient to confirm that dynamic DNS has been properly configured and is operational.

To test Dynamic DNS using radclient, follow these steps:

Step 1 Launch aregcmd and set the trace to level 4.

aregcmd
Login to the Cisco AR 4.0 server as an administrative user.

trace 4
Step 2 Launch radclient.

cd /opt/CSCOar/bin
radclient
Step 3 Create an Accounting-Start packet

acct_request Start username
Example:

set p [ acct_request Start bob ]
Step 4 Add a Framed-IP-Address attribute to the Accounting-Start packet

Step 5 Send the Accounting-Start packet

$p send
Step 6 Check the aregcmd trace log and the dns server to verify that the host entry was updated in both the forward and reverse zones.