aaa authorization commands default

Syntax

aaa authorization commands default {none | group <GROUP-LIST>}

no aaa authorization commands default

Description

Defines authorization as being local RBAC (with the name none). Or defines a sequence of remote AAA servers to be interrogated for authorization purposes.

The no form of this command removes any defined remote AAA server authorization sequence, returning the switch to local RBAC authorization only.

NOTE: Although only TACACS+ servers are supported for remote authorization, local RBAC authorization can be used with remote RADIUS authentication.

Command context

config

Parameters

local

Selects local RBAC authorization.

group <GROUP-LIST>

Specifies the list of remote AAA server group names. Predefined remote AAA group name tacacs is available. User-defined TACACS+ server group names may also be used.

It is recommended to always include the special name none as the last name in the group list. If none is omitted, and no remote AAA server is reachable, authorization will not be possible.

Authority

Administrators

Usage

The remote AAA servers are accessed in the order that the group names are listed in this command. The servers within the groups are accessed in the order in which they are added to the group. Authorization is attempted only on the first reachable server.

TACACS+ server authorization considerations

NOTE:

Use caution when configuring authorization, as it has no fail through. If the switch is not configured properly, the switch might get into an unusable state in which all command execution is prohibited.

To prevent authorization difficulties:

  • Make sure that all listed TACACS+ servers can authorize users for command execution.

  • Make sure that credential database changes are promptly synchronized across all TACACS+ servers.

  • Make sure none is included as the last name in the group list. If none is omitted, and no remote AAA server is reachable, authorization will not be possible.

  • Although not recommended, if you choose to omit none from the list, and are manipulating configuration files, special caution is necessary. If the source configuration includes tacacs authorization and you are copying configuration from an existing switch into the running configuration of a new switch, and you have not yet configured the interface or routing information to reach the AAA server, the switch will enter an unusable state, requiring hard reboot.

    To avoid getting into this situation that can occur when none has been omitted, do either of the following:

    • In the configuration source, delete or comment-out the line configuring authorization. Then, after the configuration copy and paste, manually configure authorization.

    • Move the line configuring the authorization to the end of the source configuration before copying and pasting.

Examples

Defining an authorization sequence based on a user-defined TACACS+ server group, then the default TACACS+ server group, and finally (if needed), local RBAC authorization: 

switch(config)# aaa authorization commands default group tacacs_user1 tacacs none

Enabling local RBAC authorization: 

switch(config)# aaa authorization commands default none