What does TACACS stand for and what does it do?

wrestlefever

What does TACACS stand for and what does it do? All I know that is located on port 43

Ricka182

What is TACACS, XTACACS, TACACS+, RADIUS?

All of them are protocols which allow a network access server (NAS, for example a Cisco 2511 or a 5300) to offload the user administation to a central server. There are now three versions of an authentication protocol that people commonly refer to as "TACACS", which is as acronym for "Terminal Access Controller Access Control System". The first is ordinary TACACS, which was the first one offered on Cisco boxes, and has been in use for many years. The second is an extension to the first, commonly called Extended Tacacs or XTACACS, introduced in 1990. Both of them are documented in RFC1492. The third one is TACACS+ (or tac-plus) which, despite the name, is a completely new protocol and thus is not compatible with TACACS or XTACACS.

Both TACACS and XTACACS lack many features that TACACS+ and RADIUS offer and have reached end-of-maintainance, and thus should no longer be deployed in new installation. Because of this, TACACS and XTACACS will not be discussed in the sequel.

The fourth authentication protocol which is used by Ciscos is RADIUS. It was invented by Livingston and is today supported by many NAS vendors. The functionality is similar to that of TACACS+. Support for Radius was added in IOS 11.1.