What Do You Need to Know About SMTP?


Email icon with symbolHave you ever wondered, "What is SMTP?" or "How do you get it started?" Perhaps you've come across the term while setting up an email client like Outlook or Thunderbird, and you want to learn more. Keep reading for an overview of this particular protocol, as well as common configuration steps for setting it up with popular email packages.

What is an SMTP Server?

SMTP is an acronym for "simple mail transfer protocol"-- and in a nutshell-- it is just that: a standard, rudimentary protocol for sending and receiving email over the Internet. As one of the earlier email protocols in use, SMTP was a breakthrough result of technology created in the 1980s as a lightweight, easy-to-use, email-transport mechanism.

Many protocols exist for your email accounts -- for example, IMAP and POP3 are also commonly used protocols for email delivery and retrieval. Like most people, you'll want to use SMTP strictly for sending emails as it has fewer message-routing problems than IMAP and POP3. The latter two are best for receiving your mail. In typically scenarios, your email-client application would typically connect to an email server with SMTP to send messages. Then you configure your email client to connect with IMAP or POP3 for receiving messages.

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How SMTP Works

In the case of the email address "user@myemailprovider.com," the following occurs when you send an email with a desktop email client:

  1. Your desktop email client reads your SMTP server settings.
  2. The desktop email client connects to the SMTP server at the SMTP server address mail.myemailprovider.com via port 25.
  3. The email client interacts with the SMTP server and communicates the following: the sender's SMTP, the recipient's address, and the message body.
  4. If the "to:" address is also at myemailprovider.com, it simply passes the message on to myemailprovider.com's POP3 email server for delivery to the recipient. If not, the SMTP server must communicate with the other server's SMTP server, again using port 25.
  5. The SMTP server validates that the recipient is an existing user in the system, and then the SMTP server hands the message to its POP3 or IMAP server. Finally, the message arrives at the recipient's inbox.

Popular Email Clients and SMTP Servers

Most, if not all, of your email clients support SMTP. Thunderbird, Apple Mail, Outlook, Opera Mail, and Evolution are among the more popular options. In terms of SMTP servers, by far the most prevalent program is Sendmail -- in use primarily on Linux-based servers. Windows servers also have their own implementation of SMTP.

In most cases, you won't need to worry about installing your own SMTP server -- especially in standard web-hosting scenarios. Your provider will usually provide a set of SMTP-server credentials to use when setting up your email client. They will also include IMAP and POP3 configuration information since you use these two together -- one for incoming mail, the other for outgoing mail.

Advantages of SMTP

SMTP email has many significant advantages over other email protocols. For example, SMTP email delivery is immediate, whereas POP3 can take up to 15 minutes. SMTP also enables better virus and spam control and takes up less volume for data. In short, SMTP is a lightweight, standard protocol widely in use for sending emails directly to or from other SMTP Servers. Additionally, most people often use SMTP in conjunction with POP3 or IMAP for more reliable email communications.

Carefully consider what your business needs are for your email accounts, and then you’ll be able to evaluate the worthiness of SMTP and its potential benefits.

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