What is the wellknown port number for SMTP A 21 B 22 C 23 D

What is the well-known port number for SMTP?

A. 21

B. 22

C. 23

D. 25

E. 110

Solution

D is correct. The port number for SMTP is 25.

A, B, C, and E are incorrect. A is incorrect because 21 is the port number for FTP. B is incorrect because 22 is the port number for SSH. C is incorrect because 23 is the port number for Telnet. E is incorrect because 110 is the port number for POP3.