In the OSI model, Telnet resides in which layer?

• A. Network layer
• B. Data Link layer
• C. Transport layer
• D. Application layer

Answer: (D)

Telnet is a user-facing service that provides remote terminal access, which is exactly the kind of function handled by the application layer. In the OSI model, the Application layer is where protocols like Telnet, HTTP, and FTP live to offer services directly to applications and users. Telnet relies on the Transport layer (specifically TCP) to move its data reliably and in order, but its own role is to define the remote-login session and terminal interaction, not to route, frame, or manage the lower-level transport details. It doesn’t perform routing (network layer), framing and local delivery (data link layer), or the basic transport duties itself. So the best placement for Telnet is the Application layer.