Configuring User Accounts and RBAC

Configuring User Accounts and RBAC

This chapter contains the following sections:

Configuring User Accounts and RBAC

This section describes how to configure user accounts and role-based access control (RBAC) on the Cisco Nexus 5000 Series switch.

Information About User Accounts and RBAC

You can create and manage users accounts and assign roles that limit access to operations on the Cisco Nexus 5000 Series switch. RBAC allows you to define the rules for an assign role that restrict the authorization that the user has to access management operations.

About User Accounts


Tip


The following words are reserved and cannot be used to configure users: bin, daemon, adm, lp, sync, shutdown, halt, mail, news, uucp, operator, games, gopher, ftp, nobody, nscd, mailnull, rpc, rpcuser, xfs, gdm, mtsuser, ftpuser, man, and sys.



Note


User passwords are not displayed in the configuration files.



Caution


The Cisco Nexus 5000 Series switch does not support all numeric usernames, whether created with TACACS+ or RADIUS, or created locally. Local users with all numeric names cannot be created. If an all numeric user name exists on an AAA server and is entered during login, the user is not logged in.


Characteristics of Strong Passwords

A strong password has the following characteristics:


  • At least eight characters long

  • Does not contain many consecutive characters (such as "abcd")

  • Does not contain many repeating characters (such as "aaabbb")

  • Does not contain dictionary words

  • Does not contain proper names

  • Contains both uppercase and lowercase characters

  • Contains numbers

The following are examples of strong passwords:


  • If2CoM18

  • 2009AsdfLkj30

  • Cb1955S21


Note


Clear text passwords can contain alphanumeric characters only. Special characters, such as the dollar sign ($) or the percent sign (%), are not allowed.



Tip


If a password is trivial (such as a short, easy-to-decipher password), the Cisco Nexus 5000 Series switch will reject your password configuration. Be sure to configure a strong password as shown in the sample configuration. Passwords are case sensitive.


About User Roles

User roles contain rules that define the operations allowed for the user who is assigned the role. Each user role can contain multiple rules and each user can have multiple roles. For example, if role1 allows access only to configuration operations, and role2 allows access only to debug operations, then users who belong to both role1 and role2 can access configuration and debug operations. You can also limit access to specific VSANs, VLANs and interfaces.

The Cisco Nexus 5000 Series switch provides the following default user roles:


  • network-admin (superuser)—Complete read and write access to the entire Cisco Nexus 5000 Series switch.

  • network-operator—Complete read access to the Cisco Nexus 5000 Series switch.


Note


If you belong to multiple roles, you can execute a combination of all the commands permitted by these roles. Access to a command takes priority over being denied access to a command. For example, suppose a user has RoleA, which denied access to the configuration commands. However, the users also has RoleB, which has access to the configuration commands. In this case, the users has access to the configuration commands.


About Rules

The rule is the basic element of a role. A rule defines what operations the role allows the user to perform. You can apply rules for the following parameters:


  • Command—A command or group of commands defined in a regular expression.

  • Feature—Commands that apply to a function provided by the Cisco Nexus 5000 Series switch.


    • Enter the show role feature command to display the feature names available for this parameter.

  • Feature group—Default or user-defined group of features.


    • Enter the show role feature-group command to display the default feature groups available for this parameter.

These parameters create a hierarchical relationship. The most basic control parameter is the command. The next control parameter is the feature, which represents all commands associated with the feature. The last control parameter is the feature group. The feature group combines related features and allows you to easily manage of the rules.

You can configure up to 256 rules for each role. The user-specified rule number determines the order in which the rules are applied. Rules are applied in descending order. For example, if a role has three rules, rule 3 is applied before rule 2, which is applied before rule 1.

About User Role Policies

You can define user role policies to limit the switch resources that the user can access. You can define user role policies to limit access to interfaces, VLANs and VSANs.

User role policies are constrained by the rules defined for the role. For example, if you define an interface policy to permit access to specific interfaces, the user will not have access to the interfaces unless you configure a command rule for the role to permit the interface command.

If a command rule permits access to specific resources (interfaces, VLANs or VSANs), the user is permitted to access these resources, even if they are not listed in the user role policies associated with that user.

Guidelines and Limitations for User Accounts

User account and RBAC have the following configuration guidelines and limitations:


  • You can add up to 256 rules to a user role.

  • You can assign a maximum of 64 user roles to a user account.


Note


A user account must have at least one user role.


Configuring User Accounts

You can create a maximum of 256 user accounts on a Cisco Nexus 5000 Series switch. User accounts have the following attributes:


  • Username

  • Password

  • Expiry date

  • User roles

User accounts can have a maximum of 64 user roles.


Note


Changes to user account attributes do not take effect until the user logs in and creates a new session.


To configure a user account, perform this task:

Procedure
 Command or ActionPurpose
Step 1 switch(config)# show role
 
(Optional)

Displays the user roles available. You can configure other user roles, if necessary.

 
Step 2 switch# configure terminal
 

Enters configuration mode.

 
Step 3 switch(config)# username user-id [password password] [expire date] [role role-name]
 

Configures a user account. The user-id argument is a case-sensitive, alphanumeric character string with a maximum length of 28 characters.

The default password is undefined.

Note   

If you do not specify a password, the user might not be able to log in to the Cisco Nexus 5000 Series switch.

The expire date option format is YYYY-MM-DD. The default is no expiry date.

 
Step 4 switch# show user-account
 
(Optional)

Displays the role configuration.

 
Step 5 switch# copy running-config startup-config
 
(Optional)

Copies the running configuration to the startup configuration.

 

The following example shows how to configure a user account:

switch# configure terminal
switch(config)# username NewUser password 4Ty18Rnt

switch(config)# exit
switch# show user-account
 

Configuring RBAC

Creating User Roles and Rules

Each user role can have up to 256 rules. You can assign a user role to more that one user account.

The rule number you specify determines the order in which the rules are applied. Rules are applied in descending order. For example, if a role has three rules, rule 3 is applied before rule 2, which is applied before rule 1.

Procedure
 Command or ActionPurpose
Step 1 switch# configure terminal
 

Enters configuration mode.

 
Step 2 switch(config)# role name role-name
 

Specifies a user role and enters role configuration mode. Therole-name argument is a case-sensitive, alphanumeric character string with a maximum length of 16 characters.

 
Step 3 switch(config-role)# rule number {deny | permit} command command-string
 

Configures a command rule.

The command-string argument can contain spaces and regular expressions. For example, "interface ethernet *" includes all Ethernet interfaces.

Repeat this command for as many rules as needed.

 
Step 4 switch(config-role)# rule number {deny | permit} {read | read-write}
 

Configures a read only or read and write rule for all operations.

 
Step 5 switch(config-role)# rule number {deny | permit} {read | read-write} feature feature-name
 

Configures a read-only or read-and-write rule for a feature.

Use the show role feature command to display a list of features.

Repeat this command for as many rules as needed.

 
Step 6 switch(config-role)# rule number {deny | permit} {read | read-write} feature-group group-name
 

Configures a read-only or read-and-write rule for a feature group.

Use the show role feature-group command to display a list of feature groups.

Repeat this command for as many rules as needed.

 
Step 7 switch(config-role)# description text
 
(Optional)

Configures the role description. You can include spaces in the description.

 
Step 8 switch# show role
 
(Optional)

Displays the user role configuration.

 
Step 9 switch# copy running-config startup-config
 
(Optional)

Copies the running configuration to the startup configuration.

 

The following example shows how to create user roles and specify rules:

switch# configure terminal
switch(config)# role name UserA
switch(config-role)# rule deny command clear users
switch(config-role)# rule deny read-write
switch(config-role)# description This role does not allow users to use clear commands
switch(config-role)# end
switch(config)# show role
 

Creating Feature Groups

You can create feature groups.

Procedure
 Command or ActionPurpose
Step 1 switch# configure terminal
 

Enters configuration mode.

 
Step 2 switch(config)# role feature-group group-name
 

Specifies a user role feature group and enters role feature group configuration mode.

The group-name argument is a case-sensitive, alphanumeric character string with a maximum length of 32 characters.

 
Step 3 switch# show role feature-group
 
(Optional)

Displays the role feature group configuration.

 
Step 4 switch# copy running-config startup-config
 
(Optional)

Copies the running configuration to the startup configuration.

 

Changing User Role Interface Policies

You can change a user role interface policy to limit the interfaces that the user can access.

Procedure
 Command or ActionPurpose
Step 1 switch# configure terminal
 

Enters configuration mode.

 
Step 2 switch(config)# role name role-name
 

Specifies a user role and enters role configuration mode.

 
Step 3 switch(config-role)# interface policy deny
 

Enters role interface policy configuration mode.

 
Step 4 switch(config-role-interface)# permit interface interface-list
 

Specifies a list of interfaces that the role can access.

Repeat this command for as many interfaces as needed.

For this command, you can specify Ethernet interfaces, Fibre Channel interfaces, and virtual Fibre Channel interfaces.

 
Step 5 switch(config-role-interface)# exit
 

Exits role interface policy configuration mode.

 
Step 6 switch(config-role)# show role
 
(Optional)

Displays the role configuration.

 
Step 7 switch(config-role)# copy running-config startup-config
 
(Optional)

Copies the running configuration to the startup configuration.

 

The following example shows how to change a user role interface policy to limit the interfaces that the user can access:

switch# configure terminal
switch(config)# role name UserB
switch(config-role)# interface policy deny
switch(config-role-interface)# permit interface ethernet 2/1
switch(config-role-interface)# permit interface fc 3/1
switch(config-role-interface)# permit interface vfc 30/1 
 

You can specify a list of interfaces that the role can access. You can specify it for as many interfaces as needed.

Changing User Role VLAN Policies

You can change a user role VLAN policy to limit the VLANs that the user can access.

Procedure
 Command or ActionPurpose
Step 1 switch# configure terminal
 

Enters configuration mode.

 
Step 2 switch(config)# role name role-name
 

Specifies a user role and enters role configuration mode.

 
Step 3 switch(config-role)# vlan policy deny
 

Enters role VLAN policy configuration mode.

 
Step 4 switch(config-role-vlan)# permit vlan vlan-list
 

Specifies a range of VLANs that the role can access.

Repeat this command for as many VLANs as needed.

 
Step 5 switch# show role
 
(Optional)

Displays the role configuration.

 
Step 6 switch# copy running-config startup-config
 
(Optional)

Copies the running configuration to the startup configuration.

 

Changing User Role VSAN Policies

You can change a user role VSAN policy to limit the VSANs that the user can access.

Procedure
 Command or ActionPurpose
Step 1 switch# configure terminal
 

Enters configuration mode.

 
Step 2 switch(config-role)# role name role-name
 

Specifies a user role and enters role configuration mode.

 
Step 3 switch(config-role)# vsan policy deny
 

Enters role VSAN policy configuration mode.

 
Step 4 switch(config-role-vsan)# permit vsan vsan-list
 

Specifies a range of VSANs that the role can access.

Repeat this command for as many VSANs as needed.

 
Step 5 switch# show role
 
(Optional)

Displays the role configuration.

 
Step 6 switch# copy running-config startup-config
 
(Optional)

Copies the running configuration to the startup configuration.

 

Verifying User Accounts and RBAC Configuration

To display user account and RBAC configuration information, perform one of the following tasks:

Command

Purpose

switch# show role

Displays the user role configuration

switch# show role feature

Displays the feature list.

switch# show role feature-group

Displays the feature group configuration.

switch# show startup-config security

Displays the user account configuration in the startup configuration.

switch# show running-config security [all]

Displays the user account configuration in the running configuration. The all keyword displays the default values for the user accounts.

switch# show user-account

Displays user account information.

Default User Account and RBAC Settings

The following table lists the default settings for user accounts and RBAC parameters.

Table 1  Default User Accounts and RBAC Parameters

Parameters

Default

User account password

Undefined.

User account expiry date.

None.

Interface policy

All interfaces are accessible.

VLAN policy

All VLANs are accessible.

VFC policy

All VFCs are accessible.

VETH policy

All VETHs are accessible.