[Contents] [Prev] [Next] [Index] [Report an Error]

TACACS+ Overview

With the increased use of remote access, the need for managing more network access servers (NAS) has increased. Additionally, the need for control access on a per-user basis has escalated, as has the need for central administration of users and passwords.

Terminal Access Controller Access Control System (TACACS) is a security protocol that provides centralized validation of users who are attempting to gain access to a router or NAS. TACACS+, a more recent version of the original TACACS protocol, provides separate authentication, authorization, and accounting (AAA) services.

Note: TACACS+ is a completely new protocol and is not compatible with TACACS or XTACACS.

The TACACS+ protocol provides detailed accounting information and flexible administrative control over the authentication, authorization, and accounting process. The protocol allows a TACACS+ client to request detailed access control and allows the TACACS + process to respond to each component of that request. TACACS+ uses Transmission Control Protocol (TCP) for its transport.

TACACS+ provides security by encrypting all traffic between the NAS and the process. Encryption relies on a secret key that is known to both the client and the TACACS+ process.

Table 61 describes terms that are frequently used in this chapter.

Table 61: TACACS-Related Terms

Term	Description
NAS	Network access server. A device that provides connections to a single user, to a network or subnetwork, and to interconnected networks. In reference to TACACS+, the NAS is the E-series router.
TACACS+ process	A program or software running on a security server that provides AAA services using the TACACS+ protocol. The program processes authentication, authorization, and accounting requests from an NAS. When processing authentication requests, the process might respond to the NAS with a request for additional information, such as a password.
TACACS+ host	The security server on which the TACACS+ process is running. Also referred to as a TACACS+ server.

[Contents] [Prev] [Next] [Index] [Report an Error]