TACACS+

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In computer networking, TACACS+ (Terminal Access Controller Access-Control System Plus) is a protocol which provides access control for routers, network access servers and other networked computing devices via one or more centralized servers. TACACS+ provides separate authentication, authorization and accounting services.

1 History
2 Authentication, Authorisation and Accounting
3 Protocol details
4 See also
5 References
6 External Links

[edit] History

TACACS+ is based on TACACS, but, in spite of its name, it is an entirely new protocol which is incompatible with any previous version of TACACS. TACACS+ and RADIUS have generally replaced the earlier protocols in more recently built or updated networks, although TACACS and XTACACS are still running on many older systems.

[edit] Authentication, Authorisation and Accounting

Whereas RADIUS combines authentication and authorization in a user profile, TACACS+ separates the two operations. Another difference is that TACACS+ uses the Transmission Control Protocol (TCP) while RADIUS uses the User Datagram Protocol (UDP). Most administrators recommend using TACACS+ because TCP is seen as a more reliable protocol.

The extensions to the TACACS+ protocol provide for more types of authentication requests and more types of response codes than were in the original specification.

[edit] Protocol details

TACACS+ utilizes TCP port 49. It consists three separate protocols, which can if desired by implemented on separate servers.^[1]

TACACS+ offers multiprotocol support such as IP, and AppleTalk. Normal operation fully encrypts the body of the packet for more secure communications. It is a Cisco proprietary enhancement to the original TACACS protocol.