Which authentication enables a user to authenticate themselves to multiple servers on a network with a single password without re-entering it every time?

Which authentication enables a user to authenticate themselves to multiple servers on a network with a single password without re-entering it every time?

• A. Single Sign-on Authentication
• B. Federated Identity
• C. Kerberos
• D. RADIUS

Answer: (A)

Single sign-on is about proving your identity once and then being allowed to access multiple services without retyping your password each time. When you log in, a central authority issues a token or ticket that other servers trust. As long as that token is valid, you can access those servers without entering credentials again, which is exactly the scenario described. Federated identity does enable cross-domain or cross-organizational SSO by establishing trust between different identity providers, but the everyday user experience described—one password for many servers on the same network—fits the general concept of SSO most directly. Kerberos is a concrete protocol often used to implement SSO, especially in Windows environments. It provides the ticket-based mechanism behind SSO, but the question is asking for the broader capability, which is best described by single sign-on itself. RADIUS handles authentication for network access (like VPN or Wi‑Fi) but is not about providing seamless SSO across multiple servers.

Single sign-on is about proving your identity once and then being allowed to access multiple services without retyping your password each time. When you log in, a central authority issues a token or ticket that other servers trust. As long as that token is valid, you can access those servers without entering credentials again, which is exactly the scenario described.

Federated identity does enable cross-domain or cross-organizational SSO by establishing trust between different identity providers, but the everyday user experience described—one password for many servers on the same network—fits the general concept of SSO most directly.

Kerberos is a concrete protocol often used to implement SSO, especially in Windows environments. It provides the ticket-based mechanism behind SSO, but the question is asking for the broader capability, which is best described by single sign-on itself.

RADIUS handles authentication for network access (like VPN or Wi‑Fi) but is not about providing seamless SSO across multiple servers.