Question

What layer does Protocol SMTP belong to in the DOD model? and in the OSI Model? Port#? What does it stand for and what does it do?

A) DOD Model: Application, OSI Model: Application, Port: 25, Stands for: Simple Mail Transfer Protocol, Function: Email transmission
B) DOD Model: Application, OSI Model: Presentation, Port: 587, Stands for: Secure Mail Transfer Protocol, Function: Secure email transmission
C) DOD Model: Presentation, OSI Model: Session, Port: 110, Stands for: Server Mail Transfer Protocol, Function: Server-side email handling
D) DOD Model: Transport, OSI Model: Transport, Port: 143, Stands for: Mail Transport Protocol, Function: General mail transport

Answer 1

Simple Mail Transfer Protocol (SMTP) belongs to the Application layer in both the DOD and OSI models, operates on port 25, and is used for email transmission.

Step-by-step explanation:

The protocol SMTP belongs to the Application layer in both the Department of Defense (DOD) model and the Open Systems Interconnection (OSI) model. The default transmission control protocol port number for SMTP is 25. SMTP stands for Simple Mail Transfer Protocol, and its primary function is the transmission of email over IP networks. SMTP is an Internet standard for electronic mail (email) transmission across Internet Protocol (IP) networks. SMTP is used to send messages to a server's mail transfer agent (MTA), as well as to transfer mail between MTAs and mail delivery agents (MDAs).