Introduction to Computer Networking

Simple Mail Transfer Protocol (SMTP)

Simple Mail Transfer Protocol (SMTP)

Introduction

In this blog, we are going to discuss a simple mail transfer protocol which is one of the application layer protocols. Before learning about the simple mail transfer protocol (SMTP), you must have the basic understanding of the email first. So, let us get started. The discussion would be focussed on these topics: What is an email, What is a SMTP, Working of SMTP, Types of simple mail transfer protocol, advantages and disadvantages of simple mail transfer protocol. We believe that this blog has been helpful for you.

Email

The email is one of the ways to send and receive information in the form of messages across the internet. Although email and traditional mail look similar, there are key differences between them. The difference between traditional mail and email is that a traditional mail is generally referenced with the name of the receptionist, street address, city, state, and zip code whereas an email is always written in a standard format but it differs a lot from a traditional mail. Moreover, a traditional mail can take a couple of days or a couple of weeks to get delivered but an email can be delivered instantly.

Simple Mail Transfer Protocol

In today's technology world, email is emerging as one of the most crucial services on the internet. The simple mail transfer protocol defines a set of communication guidelines that allows us to transfer an electronic mail through the internet. The main purpose of the simple mail transfer protocol is to make communication rules between the servers.

The servers can identify themselves and declare what type of communication they are expecting. They can also deal with errors like incorrect email addresses. You must have noticed that if you send a message to a wrong email address then it reverts back to you with some error message.

Working of Simple Mail Transfer Protocol

Now we will discuss the working of the simple mail transfer protocol step by step:

1. Composition of email: The electronic mail is composed with the help of a mail user agent which is also known as MUA. The mail user agent (MUA) is a set of instructions (program) that is used to send and receive the mail. The message has primarily two components: header and body.

The header contains the light information like sender’s address whereas body is the crucial part and includes the main information to be delivered.

2. Submission of email: Once the email is composed successfully, the mail client becomes active and pushes the completed email to the SMTP server.

3. Delivery of email: The email address is composed of two components, domain name and the user name of the receptionist. For example, In connect@boardinfinity.com, connect is the username and boardinfinity.com is the domain name. If the domain name of the receptionist turns out to be different from the sender’s domain name then in such scenarios MSA will pass a message to the Mail Transfer Agent (MTA).  

4. Receipt and manipulation of the mail: The moment incoming message is gathered, the exchange server is responsible to transfer it to the incoming server (Mail delivery agent).

5. Access and retrieval of the mail: The Mail User Agent (MUA) is responsible to retrieve the collected mail in MDA.

Types of Simple Mail Transfer Protocol

The simple mail transfer protocol is of two types:

1. End-to-end method: The end to end method is feasible to provide communication between  different organizations. The SMTP client makes the communication with the destination host SMTP for smooth transmission of the mail to the destination.

2. Store and forward method: The store and forward method works in a way that it firstly stores the message sent by the source device on a server. The server is then responsible to explore the destination device from the database of the servers.

Advantages of Simple Mail Transfer Protocol

  • The SMTP allows us user to mail in bulk.
  • It covers a large area.
  • Low cost.
  • Reliable email delivery.

Disadvantages of Simple Mail Transfer Protocol

  • Security is the bigger problem.
  • The firewalls can block the common port of SMTP.
  • If the message exceeds a certain length, then in such cases SMTP may reject the entire message.
  • Sometimes delivery gets delayed because of back and forth processing between the servers.

Conclusion

In this blog, we discussed the simple mail transfer protocol. We majorly discussed these topics: What is an email, What is a SMTP, Working of SMTP, Types of simple mail transfer protocol, advantages and disadvantages of simple mail transfer protocol. We believe that this blog has been helpful for you.