Which of the following transport layer protocols is used to support electronic mail?

Select one answerSingle correct

Pick an option to check

Solution

Step-by-step verified solution

Official answer: C) TCP

Principles of Layering

Electronic mail (SMTP) is an application layer protocol that requires reliable and connection-oriented data transfer. Therefore, it uses TCP (Transmission Control Protocol) at the transport layer (typically on port 25).

SMTP is an application layer protocol, not a transport layer protocol.
IP operates at the network layer.
UDP is an unreliable, connectionless transport protocol and is not used by standard email transfer.

Thus, the correct transport layer protocol is TCP (Option C).

Try the question first, then check your work.

Think the official key or this write-up is wrong?

Report error or challenge

Examiner trap

The misconception this question tests

This Principles of Layering previous year question is Q22 of the GATE CSE 2012 paper. Find more GATE CSE PYQs on Principles of Layering in Computer Networks, or browse all GATE CSE PYQs.

Free diagnostic

Where do you stand for GATE?

Take the 20-minute diagnostic: the 3 topics that cost you the most marks, and a rank range. Or sit 5 related Principles of Layering PYQs now with no account.

One GATE CSE PYQ every morning

An official question by email at 7 AM IST, with a link to its verified solution. Unsubscribe in one click.

Principles of Layering in GATE CSE

Principles of Layering has 12 GATE CSE PYQs across 10 papers from 2011 to 2025. 9 of them are 1-mark MCQs like this one, and GATE CSE 2012 has 3.

How GATE tests Principles of Layering

More from GATE CSE 2012

Independent practice explanation verified by the GateAI team. GATE is conducted by the IITs; question text follows the official paper.