Which of the following protocols provide authentication, authorization, and accounting services?

User Accounts

There are two general user account types: admin and monitor. As admin, the user is privileged to execute all the available operations. As monitor, the user can execute operations that display system configuration and status, or set terminal settings.

AAA is a term describing a framework for intelligently controlling access to computer resources, enforcing policies, auditing usage, and providing the information necessary to bill for services. These combined processes are considered important for effective network management and security. The AAA feature allows you to verify the identity of, grant access to, and track the actions of users managing the system. The Remote Access Dial-In User Service (RADIUS) or Terminal Access Controller Access Control device Plus (TACACS+) or Lightweight Directory Access Protocol (LDAP) protocols are supported by the MLNX-OS switch.

• Authentication—authentication provides the initial method of identifying each individual user, typically by entering a valid username and password before access is granted. The AAA server compares a user's authentication credentials with the user credentials stored in a database. If the credentials match, the user is granted access to the network or devices. If the credentials do not match, authentication fails and network access is denied.

• Authorization—following the authentication, a user must gain authorization for performing certain tasks. After logging into a system, for instance, the user may try to issue commands. The authorization process determines whether the user has the authority to issue such commands. Simply put, authorization is the process of enforcing policies: determining what types or qualities of activities, resources, or services a user is permitted. Usually, authorization occurs within the context of authentication. Once you have authenticated a user, they may be authorized for different types of access or activity.
• Accounting—the last level is accounting, which measures the resources a user consumes during access. This includes the amount of system time or the amount of data a user has sent and/or received during a session. Accounting is carried out by logging of session statistics and usage information, and is used for authorization control, billing, trend analysis, resource utilization, and capacity planning activities.

Authentication, authorization, and accounting services are often provided by a dedicated AAA server, a program that performs these functions. Network access servers interface with AAA servers using the Remote Authentication Dial-In User Service (RADIUS) protocol.

User Re-authentication

Re-authentication prevents users from accessing resources or perform tasks for which they do not have authorization. If credential information (e.g., AAA server information like IP address, key, port number, and so forth) that has been previously used to authenticate a user is modified, that user gets immediately logged out and then asked to re-authenticate.

RADIUS

RADIUS (Remote Authentication Dial-In User Service), widely used in network environments, is a client/server protocol and software that enables remote access servers to communicate with a central server to authenticate dial-in users and authorize their access to the requested system or service. It is commonly used for embedded network devices such as routers, modem servers, switches and so on. RADIUS is currently the de-facto standard for remote authentication. It is prevalent in both new and legacy systems.

It is used for several reasons:

• RADIUS facilitates centralized user administration
• RADIUS consistently provides some level of protection against an active attacker

TACACS+

TACACS (Terminal Access Controller Access Control System), widely used in network environments, is a client/server protocol that enables remote access servers to communicate with a central server to authenticate dial-in users and authorize their access to the requested system or service. It is commonly used for providing NAS (Network Access Security). NAS ensures secure access from remotely connected users. TACACS implements the TACACS Client and provides the AAA (Authentication, Authorization, and Accounting) functionalities.

TACACS is used for several reasons:

• Facilitates centralized user administration
• Uses TCP for transport to ensure reliable delivery
• Supports inbound authentication, outbound authentication and change password request for the authentication service
• Provides some level of protection against an active attacker

LDAP 

LDAP (Lightweight Directory Access Protocol) is an authentication protocol that allows a remote access server to forward a user's log-on password to an authentication server to determine whether access can be allowed to a given system. LDAP is based on a client/server model. The  acts as a client to the LDAP server. A remote user (the remote administrator) interacts only with the , not with the back-end server and database.

LDAP authentication consists of the following components:

• A protocol with a frame format that utilizes TCP over IP
• A centralized server that stores all the user authorization information

• A client: in this case, the 

Each entry in the LDAP server is referenced by its Distinguished Name (DN). The DN consists of the user-account name concatenated with the LDAP domain name. The following is an example DN where the the user-account name is John: 

uid=John,ou=people,dc=domain,dc=com

LDAP supports user membership in groups. If remote user is a member of admin or monitor group, it will be logged with admin or monitor capabilities respectively.
Supported group names for mapping are as follows:

• admin
• monitor

Supported group types (objectClass) on LDAP server side are as follows:

• groupOfNames
• posixGroup

System Secure Mode

System secure mode is a state that configures the switch system to run secure algorithms in compliance with FIPS 140-2 requirements. In this mode, unsecure algorithms are disabled and unsecure feature configurations are disallowed.

In this mode the system supports Federal Information Processing Standards (FIPS) 140-2, Security Requirements for Cryptographic Modules, which is a NIST (National Institute of Standards and Technology) publication that specifies the requirement for system cypher functionality.

When this mode is activated, all the modules which are used by the system are verified to work in compliance with the secure mode.

Note that if system fails to load in secure mode it is loaded in non-secure mode.

Prerequisites:

1. Disable SNMPv1 and v2.

switch (config) # no snmp-server enable communities

2. Only allow SNMPv3 users with sha and aes-128.

switch (config) # snmp-server user <username> v3 auth sha <password1> priv aes-128 <password2>

3. Only allow SNMPv3 traps with sha and aes-128.

switch (config) # snmp-server host <ip-address> informs version 3 user <username> auth sha <password1> priv aes-128 <password2>

4. Only allow SSHv2.

switch (config) # ssh server min-version 2

5. Enable SSH server strict security mode.

switch (config) # ssh server security strict

6. Disable HTTP access.

switch (config) # no web http enable

7. Enable HTTPS strict cyphers.

switch (config) # web https ssl ciphers TLS1.2

If a necessary prerequisite is not fulfilled the system does not activate secure mode and issues an advisory message accordingly.

Secure mode is not supported on modular switch systems.

To activate secure mode, do the following:

switch (config) # system secure-mode enable

Warning! Configuration is about to be saved and the system will be reloaded.
Type 'YES' to confirm the change in secure mode: YES

To deactivate secure mode, do the following:

switch (config) # no system secure-mode enable

Warning! Configuration is about to be saved and the system will be reloaded.
Type 'YES' to confirm the change in secure mode: YES

To verify secure mode configuration and state, do the following:

switch (config)# show system secure-mode

Secure mode configured: yes
Secure mode enabled: yes