Terminal Access Controller Access Control System

What Does Terminal Access Controller Access Control System Mean?

Terminal access controller access control system (TACACS) is an authentication protocol used for remote communication with any server housed in a UNIX network. TACACS provides an easy method of determining user network access via remote authentication server communication. The TACACS protocol uses port 49 by default.


TACACS uses allow/deny mechanisms with authentication keys that correspond with usernames and passwords. Cisco, which designed and launched the TACACS protocol, is also its owner.

Techopedia Explains Terminal Access Controller Access Control System

The TACACS protocol, which has a very simple working mechanism, accepts a user query from a remote server and forwards this query for necessary action to the authentication server. The authentication server may allow or deny a user query on the host’s behalf. The host is a system or platform that runs on the server. The query result is sent to the query initiator as a feedback response.

The routing node used in dialup connections during the user login process allows or denies user access based on the query’s response.


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