authentication server

An authentication server is an application that facilitates authentication of an entity that attempts to access a network. Such an entity may be a human user or another server. An authentication server can reside in a dedicated computer, an Ethernet switch, an access point or a network access server.

Authentication is the process of determining whether someone or something is actually who or what it declares itself to be. When a potential subscriber accesses an authentication server, a username and password may be the only identifying data required. In a more sophisticated system called Kerberos, the subscriber must request and receive an encrypted security token that can be used to access a particular service. RADIUS (Remote Authentication Dial-In User Service) is a commonly used authentication method. TACACS+ (Terminal Access Controller Access Control System Plus) is similar to RADIUS but is used with Unix networks. RADIUS employs UDP (User Datagram Protocol) and TACACS+ employs TCP (Transmission Control Protocol.

Some specialized authentication servers employ smart cards or biometric verification in addition to one or more of the above mentioned technologies.

This was last updated in July 2007

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