SMTP protocol works on which port number?

A. 80

B. 143

C. 110

D. 25

Correct Answer is :

D. 25

Explanation

<p><span style="font-size: 14px;">SMTP (Simple Mail Transfer Protocol) is used for sending emails.</span></p><p><span style="font-size: 14px;">The default port for SMTP is 25.</span></p><p><span style="letter-spacing: 0.01rem;">Other commonly used SMTP ports:</span></p><ul><li><span style="font-size: 14px;">587 → Secure email submission (modern standard)</span></li><li><span style="font-size: 14px;">465 → SMTPS (older secure method)</span></li></ul>