Which authentication type relies on an identity signal from the same system requesting authentication?

Which authentication type relies on an identity signal from the same system requesting authentication?

• A. Out-of-Band Authentication
• B. RADIUS
• C. TACACS+
• D. In-Band Authentication

Answer: (D)

This centers on where the identity signal comes from in the authentication flow. In-Band Authentication means you provide your credentials over the same channel that is requesting access—the login prompt on the same device, for example, typing a username and password at a workstation or VPN client. The proof of identity travels with that same connection. This is different from Out-of-Band Authentication, which uses a separate channel or device to verify who you are (like a push notification to a phone, a hardware token code, or a phone call). RADIUS and TACACS+ are authentication protocols used to authorize access on networks; they describe how credentials are handled on servers, not the location of the identity signal relative to the access request. So the correct type is In-Band Authentication.