RADIUS vs. TACACS

Attribute	RADIUS	TACACS
Authentication	Yes	Yes
Authorization	Yes	Yes
Accounting	Yes	Yes
Protocol	UDP	TCP
Port	1812	49
Encryption	Yes	Yes

Introduction

Remote Authentication Dial-In User Service (RADIUS) and Terminal Access Controller Access-Control System (TACACS) are both protocols used for network access control and authentication. While they serve similar purposes, there are key differences between the two that make them suitable for different environments and requirements.

Authentication

RADIUS is primarily used for authentication, authorization, and accounting (AAA) in network access control. It is widely supported by networking devices and operating systems, making it a popular choice for organizations looking to secure their networks. TACACS, on the other hand, is more focused on authentication and authorization, with less emphasis on accounting. This makes TACACS a preferred option for organizations that prioritize security over accounting capabilities.

Security

When it comes to security, TACACS is considered more secure than RADIUS. TACACS encrypts the entire authentication process, including the username and password, providing an extra layer of security. RADIUS, on the other hand, only encrypts the password, leaving the username vulnerable to interception. This makes TACACS a better choice for organizations that require a higher level of security for their network access control.

Scalability

Both RADIUS and TACACS are scalable solutions that can handle a large number of users and devices. However, RADIUS is better suited for larger networks with a high volume of authentication requests. RADIUS servers can be distributed across multiple locations to handle the load, making it a more scalable option for organizations with complex network infrastructures. TACACS, on the other hand, is better suited for smaller networks with fewer authentication requests, as it may struggle to handle the load in larger environments.

Vendor Support

RADIUS is an open standard protocol that is supported by a wide range of networking vendors, including Cisco, Juniper, and Microsoft. This makes it a versatile option for organizations that use a variety of networking equipment from different vendors. TACACS, on the other hand, is primarily associated with Cisco devices, as it was originally developed by Cisco Systems. While TACACS can be used with other vendors, it may not be as widely supported as RADIUS, making it a less versatile option for organizations with diverse networking environments.

Accounting

One of the key differences between RADIUS and TACACS is their accounting capabilities. RADIUS includes accounting as part of its AAA functionality, allowing organizations to track and monitor user activity on the network. TACACS, on the other hand, focuses more on authentication and authorization, with limited accounting capabilities. This makes RADIUS a better choice for organizations that require detailed logging and reporting of user activity, while TACACS may be sufficient for organizations that prioritize authentication and authorization over accounting.

Conclusion

In conclusion, RADIUS and TACACS are both valuable protocols for network access control and authentication, each with its own strengths and weaknesses. RADIUS is a versatile option that is widely supported by networking vendors and offers robust accounting capabilities. TACACS, on the other hand, is more secure and focused on authentication and authorization, making it a preferred choice for organizations that prioritize security over accounting. Ultimately, the choice between RADIUS and TACACS will depend on the specific requirements and priorities of the organization, as well as the size and complexity of the network environment.