HWTACACS

tacacs-messaging

What is HWTACACS?

HWTACACS (Huawei Terminal Access Controller Access-Control System) is a AAA protocol that is developed by Cisco. After a while HWTACACS has became a standard protocol that is supported by all vendors. There is also another standard protocol called RADIUS. If you would like to learn more on RADIUS, you can check RADIUS Protocol lesson. You can also reach related rfc, here.

 

Key Point: HWTACACS is a Huawei protocol used for AAA (Authentication, Authorization, and Accounting) in network devices.

 

The main duty of HWTACACS+ is providing device administration. It can also used for netwok access. With this AAA Protocol, network administrators are authenticated to log in the network devices like router, switches, firewalls, etc. in the network.

 

Key Point: HWTACACS separates Authentication from Authorization, allowing admins to control who can log in and what commands they can execute.

 

AAA Protocols can encrypt the full packet or only the passwords. Here,HWTACACS provides a full packet encryption. It encrypts the whole packet. But RADIUS do not encrypt the full packet. It encrypts only passwords, not the full packets. This makes Terminal Access Controller Access-Control System more secure AAA Protocol than RADIUS Protocol.

 

Warning: HWTACACS encrypts only the body of the packet, not the header, so proper key management is crucial for security.

 

HWTACACS is also a Client/Server protocol. For different duties (Authenticaiton , Authorization, Accounting), different messages are used between Server and Client. One side is the Client side and the other is the Server side. The messaging between these two end build the session.

 

HWTACACS uses TCP (Transmission Control Protocol) as a Trasnport Protocol. The TCP Port that is used for this protocol is 49.

 

Key Point: HWTACACS always uses TCP port 49 for communication between network devices and the AAA server. Ensure this port is open and restricted to trusted hosts for secure operation.

 

HWTACACS provide a separate AAA ( Authentication, Authorization, Accounting). This is not separate in RADIUS. In Radius, Authentication and Authorization is combined. Only Accounting is separate.

 

Terminal Access Controller Access-Control System  uses command logging. We can determine that which user enter which command. This is especially very useful for troubleshooting issues.

 

Warning: HWTACACS requires a dedicated shared secret key between client and server. Weak or reused keys can compromise security.

 

As you know there are different priviledge levels for any user in a system. There are 15 privilege levels used with HWTACACS.

 

Huawei Terminal Access Controller Access-Control System has three steps messaging. As we have talked about before, it has separate pahases for Authentication , Authorization and Accounting. These pahases are:

  • Authentication
  • Authorization
  • Accounting

 

Key Point: HWTACACS (Huawei Terminal Access Controller Access-Control System) uses a three-step messaging process: Authentication, Authorization, and Accounting to securely manage user access to network devices.

 

For these phases, request and reply messages are sent between Client and Server. This is the typical mechanism for a Client/Server Protocol.


tacacs-messaging
In this article, we have talked about one of the imporant protocols of AAA (Authentication, Authorization, Accounting). If you would like to learn other important AAA Protocol, RADIUS, you can check RADIUS lesson. And you can also learn the similarities and differences of these two protocols on TACACS vs RADIUS lesson.

 

Real Life Use Case: HWTACACS is widely used by network administrators to centralize login management on Cisco devices, allowing role-based access control and detailed command accounting.

 


Frequently Asked Questions

How Does HWTACACS Differ From RADIUS?

RADIUS combines authentication and authorization and primarily secures only the password. While HWTACACS separates authentication, authorization and accounting. This provides more granular control over command permissions and ensures all communication is encrypted, not just the password.

 


Which Port Does HWTACACS Use?

HWTACACS uses TCP port 49 for communication between network devices and the AAA server.

 


Does HWTACACS Reliable?

Because HWTACACS is TCP-based, it ensures reliable delivery of authentication and authorization messages.

 


What are the Three Steps in HWTACACS Cmmunication?

HWTACACS follows a three-step messaging process:

  • Authentication: Verify the user’s identity.
  • Authorization: Determine what commands or actions the user is allowed to perform.
  • Accounting: Record user activity for auditing and monitoring purposes.

 


Why Should Network Administrators Use HWTACACS?

HWTACACS allows centralized and secure management of network devices, provides role-based access control, encrypts all AAA communications and offers detailed logging for auditing. It is especially useful in large enterprise networks where multiple administrators manage critical devices.

 

Lesson tags: AAA, TACACS+
Back to: HCIA-Datacom (HCNA) > AAA

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