Prerequisites for Encrypted Vendor-Specific Attributes
Before the RADIUS server can accept tagged and encrypted VSAs, you must configure your server for AAA authentication and authorization and to accept PPP calls.
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The Encrypted Vendor-Specific Attributes feature provides users with a way to centrally manage filters at a RADIUS server and supports the following types of string vendor-specific attributes (VSAs):
Tagged String VSA (similar to Cisco VSA type 1 (Cisco:AVPair (1)) except that this new VSA is tagged)
Encrypted String VSA (similar to Cisco VSA type 1 except that this new VSA is encrypted)
Tagged and Encrypted String VSA (similar to Cisco VSA type 1 except that this new VSA is tagged and encrypted)
Cisco:AVPairs specify additional authentication and authorization information in the form an Attribute-Value Pair (AVPair) string. When Internet Engineering Task Force (IETF) RADIUS attribute 26 (Vendor-Specific) is transmitted with a vendor-Id number of “9” and a vendor-type value of “1” (which means that it is a Cisco AVPair), the RADIUS user profile format for a Cisco AVPair looks as follows: Cisco:AVPair = “protocol:attribute=value”.
Before the RADIUS server can accept tagged and encrypted VSAs, you must configure your server for AAA authentication and authorization and to accept PPP calls.
The figure below displays the packet format for the Tagged String VSA:
To retrieve the correct value, the Tag field must be parsed correctly. The value for this field can range only from 0x01 through 0x1F. If the value is not within the specified range, the RADIUS server ignores the value and considers the Tag field to be a part of the Attribute String field.
The figure below displays the packet format for the Encrypted String VSA:
The Salt field ensures the uniqueness of the encryption key that is used to encrypt each instance of the VSA. The first and most significant bit of the Salt field must be set to 1.
![]() Note |
Vendor-type (36) indicates that the attribute is an encrypted string VSA. |
The figure below displays the packet formats for each of the newly supported VSAs:
This VSA is similar to encrypted string VSAs except this VSA has an additional Tag field. If the Tag field is not within the valid range (0x01 through 0x1F), it is considered to be part of the Salt field.
The Encrypted Vendor-Specific Attributes feature requires no configuration. To verify that RADIUS-tagged and encrypted VSAs are being sent from the RADIUS server, use the following command in privileged EXEC mode:
Command |
Purpose |
---|---|
|
Displays information associated with RADIUS. The output of this command shows whether tagged and encrypted VSAs are being sent from the RADIUS server. |
The following example shows how to configure a network access server (NAS) with a basic configuration using tagged and encrypted VSAs. (This example assumes that the configuration required to make PPP calls is already enabled.)
aaa new-model
aaa authentication ppp default group radius
aaa authorization network default group radius
!
radius-server host 10.2.2.2 auth-port 1645 acct-port 1646
radius-server key cisco
The following is an example of user profile on a RADIUS server that supports tagged and encrypted string VSAs:
mascot Password = "password1"
Service-Type = NAS-Prompt,
Framed-Protocol = PPP,
Cisco:Cisco-Enc = "ip:route=10.0.0.0 255.0.0.0"
Cisco.attr Cisco-Enc 36 tag-encstr(*,*)
Related Topic |
Document Title |
---|---|
Cisco IOS commands |
Cisco IOS Master Commands List, All Releases |
RADIUS Attributes |
Cisco IOS XE Security Configuration Guide: Securing User Services , Release 2 |
Media-Independent PPP and Multilink PPP |
Configuring Media-Independent PPP and Multilink PPP feature module. |
Authentication |
Configuring Authentication feature module. |
Authorization |
Configuring Authorization feature module. |
Standard |
Title |
---|---|
None. |
-- |
MIB |
MIBs Link |
---|---|
None. |
To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL: |
RFC |
Title |
---|---|
RFC 2865 |
Remote Authentication Dial In User Service (RADIUS) |
RFC 2868 |
RADIUS Attributes for Tunnel Protocol Support |
Description |
Link |
---|---|
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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.
Feature Name |
Releases |
Feature Information |
---|---|---|
Encrypted Vendor-Specific Attributes |
Cisco IOS XE Release 2.3 |
The Encrypted Vendor-Specific Attributes feature provides users with a way to centrally manage filters at a RADIUS server and supports the Tagged String, Encrypted String, and Tagged and Encrypted String vendor-specific attributes (VSAs). In Cisco IOS XE Release 2.3, this feature was introduced on the Cisco ASR 1000 Series Aggregation Services Routers. |