Email Delivery - How SMTP Protocols

When you decide to use an email delivery service to send emails you start to put an SMTP server to work. SMTP is short for Simple Mail Transfer Protocol. Your mail server will communicate with the SMTP server by using the SMTP language. Communication with the SMTP email server will eventually lead to the sending and receiving of the email.

Starting the Conversation

Your email client will start the conversation by connecting to the server and saying EHLO. This is a command that asks the server for information on any extra features that the server may have. For example, this could include delivery status notification.

However, there are some servers that do not allow email clients to use the command EHLO. In this case, the email server would have to use the command HELO. This command does not recognize the existence of any extra features and will simply ask the SMTP server for the domain.

Sending the Email

In order to send an email the client will start the command with MAIL FROM:. The client will then include your email address. There has to be brackets around the address in order for the SMTP server to understand what the email address is. Once the server accepts your address, the email client will need to give the server the address of the person who is receiving the email. The email client will need to use the RCPT TO: command.

Once the server accepts this command it will then save the mail locally. Your email will be saved with other emails that have are waiting to be sent. The server sends these emails in intervals. Although it is normally every thirty minutes, the length of the intervals depends on how the server has been configured. For example, there are some servers that are able to send out emails as soon as the server gets the command to do so.

Data

The data of an email is made up of the emails header fields and the body field. The email client will use the command DATA to tell the server to accept the message. After this command, the server will accept all of the header fields first. It will then accept the body of the email. All of this is stored in one large block of text.

The email client tells the server that all input has been finished by using one dot. This dot should be on a line by itself. If you input all of this information without the help of the email client you will be able to use a name that is different from the one that the email client uses in the TO: field. For example, you have the power to use the “Recipient List Suppressed” command if you wish to do so.

Do It Yourself

By knowing how to do this yourself, you will be able to send out as many emails as you need if your email client is not able to do this for you. Remember that once you have finished typing out all of the required commands and providing all of the needed information, you can cancel the conversation with the server by using the QUIT command.

In order to use the SMTP yourself you can telnet the outgoing mail server by going to port 25. Port 25 is normally the port that features the SMTP server that you need to get contact. You can find out what the address is for the outgoing mail server by going into your email client’s account settings. Open a command prompt and type “telnet <mailserver>25”. Proceed to communicate with the server by using the protocols.

Thanks for reading this article on SMTP Servers and protocols. For more information be sure to check back next week for more updates.

Faizan Ahmad

About the Author:

This article is posted by Faizan who is the Author and Founder of TechSenser. He is a Professional Blogger from India and a passionate writer about Technology, Gadgets, How-to-Guides, etc. You can connect him on Google+.