TACACS+ (Terminal Access Control Access Server Plus) provides access control for routers, network access servers and other networked computing devices via one or more cen tralized servers. TACACS+ provides separate authentication, authorization and accounting services. The full describe of TACACS+ protocol you can find at ftp://ftp-eng.cisco.com/pub/tacacs/tac-rfc.1.78.txt or http://search.ietf.org/internet-drafts/draft-grant-tacacs-02.txt or in /doc directory of this distribution. TACACS+ is used mostly for Cisco devi ces (but I saw it support in 3Com HiPer too, and read about it in Cabletron devices) . RADIUS - this is other similar protocol, which working throught UDP and have way to use vendor specific attributes. RADIUS - more compatible protocol but less functional, may be later we will do R ADIUS support in tacppd.