What is SMTP?

SMTP is a simple mail transfer protocol. In SMTP, we send email messages to one another over the internet. But in SMTP, we add one receiver’s email address at a time to send the message. If we want to send the messages to multiple recipients, we can add the email address to CC and BCC. They have more storage and also work on a WAN, which means we send the message to a receiver outside the internet. It is also responsible for handling errors while sending messages, like if a person enters the wrong email address and sends the message “message not delivered.”.

Working of SMTP

• The first process of working with SMTP is the mail composition, where the email consists of a body and subject. In the body section, we can write the content and subject that represent the heading.

• The second process is the mail delivery, which requires the receiver’s email address, like person@gmail.com, where person represents the username and gmail.com represents the domain name. If the receiver domain name and sender domain name are the same, then the Mail Transfer Agent (MTA) connects to the server and transfers the message, but if both domain names are different, then the MTA finds the domain name in the DNS and, if found, connects to the server and transfers the message.

• The third process is that if the server receives the email, it goes to the mail delivery agent. The MDA waits for the email until the user gets it.

Components of SMTP

• MUA: MUA stands for Mail User Agent, which is useful for sending and receiving messages.
• MSA: MSA stands for Mail Submission Agent that communicates with MUA to transfer the email messages.
• MTA: MTA stands for Mail transfer agent that transfers the mail to another with the help of SMTP.
• MDA: MDA stands for Mail Delivery Agent, which is useful for delivering mail to the local system.

Advantages of SMTP

• Easy to use and implement.
• It is used in a wide-area network.
• They have more storage.
• It is easy to handle bulk mailings.

Disadvantages of SMTP

• They have a bigger problem in terms of SMTP security.
• Sometimes the delivery of a message gets delayed.
• Blocking of SMTP ports because of firewalls.

SMTP and LMTP are the transmission protocols. The full form of SMTP is Simple Mail Transfer Protocol, as the name suggests; it simply transfers the email messages to another over the internet. It works over the wide-area network and the port 25 used in SMTP. The full form of LMTP is a Local Mail Transfer Protocol that transfers email messages to another locally. It does not work over a wide network, and port 24 is used in LMTP. In this article, we will cover the explanation of SMTP and LMTP and their differences.