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What Is an SMTP Server?

An SMTP server is dedicated to sending and receiving large quantities of emails. Learn more about SMTP servers and their impact on email marketing here.

From small to large businesses, email is still a key driver for customer acquisition and retention. However, managing emails is difficult because most people send and receive dozens daily. So, how can you handle your customers’ emails as a business owner?

This is where SMTP servers come in. A simple mail transfer protocol (SMTP) server is a communication protocol that enables you to send and receive emails. Without an SMTP server, you can't send your email to recipients. The server also examines if an active email account is transmitting the outbound message.

If the email isn't delivered, SMTP protocols ensure the message is returned to the sender. Returned messages contain details to inform the sender they either have an inaccurate email address or the recipient’s server has blocked emails from the sender’s ID. Therefore, it's a good idea for every business owner to have an SMTP server.

How do SMTP servers work?

You send mail from your email address, such as, to a given recipient, such as, using your email service provider. The webmail is known as the MUA, or message user agent.

The email is sent through port 25 to an SMTP server provided by your mail client, operating as a Mail Transfer Agent. The client and server start a brief conversation where the latter verifies all the information about the transmission of the message (sender, recipient, and domains). The mail server authenticates the email sender and places the new email in the recipient's inbox. Remember that the SMTP language only discusses the message's transmission and not its contents.

The email is immediately sent if the recipient’s domain has an account connected to the server. If that's not the case, the SMTP transmits it to another incoming server closer to the recipient. The domain server establishes a connection with the website server, which receives and stores the email.

What if the recipient’s server is unavailable or busy? The SMTP host simply forwards the message to a backup server. If none is available, the email is held, and the delivery is retried periodically. After a determined time, it marks the message as undelivered.

SMTP vs. IMAP vs. POP3

Specialized TCP/IP protocols called SMTP, POP3, and IMAP are used to send and receive emails. To meet the needs of modern applications, it's important to understand these protocols.


When utilizing the IMAP protocol, the email client establishes a connection to the server, scans for new messages, and saves them as temporary files in the cache. At first, the server only downloads the date, sender, and subject. Only when you open the mail will the content download. Therefore, it's possible to access the email's content without downloading any attached files utilizing this protocol.

The server updates when an email is edited, deleted, or has its status changed from unread to read. This procedure aids in reflecting the current status of emails across various devices.

The major differences between IMAP and SMTP include:

  • SMTP is used to transfer data, while an IMAP server is used to retrieve messages.
  • SMTP transfers data between servers, while IMAP facilitates communication between the server and client.
  • While SMTP allows users to organize emails on client storage, IMAP allows users to manage emails on the server.


A more user-friendly approach to accessing mailboxes is through Post Office Protocol. POP3 allows you to access emails even if you're not connected to the internet because it sends emails from the server to the email client.

The client connects to the POP3 server when a user checks for new emails. The email client then submits its username and password to the server for authentication. The client sends text-based commands to retrieve all email messages as soon as it connects. It then deletes the server copies and disconnects from the server after saving the downloaded messages as new emails on the user's local system.

The differences between POP3 and SMTP include:

  • POP3 is a pull protocol, whereas SMTP is a push protocol.
  • Emails are delivered via SMTP from the sender's device to the recipient's inbox and via POP3 from the recipient's mail server to the recipient's computer.
  • POP3 works between the recipient and the recipient's mail server, while SMTP works between the incoming and outgoing mail server.


The differences between POP3 and IMAP include:

  • While IMAP displays the message header before downloading the email, POP3 downloads the email all at once.
  • POP3 takes emails from servers, transfers them to a single computer, and deletes them. IMAP syncs the email across many devices so that it can be accessed via various channels after being stored on the server.
  • Organizing emails in the mail server mailbox isn't possible with POP3, but it's possible with IMAP.

Importance of SMTP servers in email marketing

SMTP servers are important in email marketing and can handle a large volume of emails at once. Personal emailing works well with standard SMTP servers, and many standard emailing programs are free.

Although public and free SMTP servers can be helpful for people who send a few emails, you might desire a private SMTP server if you transmit large numbers of emails or ones with sophisticated messages.

Advantages of an SMTP server include:

  • Provides structure for bulk emails: SMTP servers enable you to scale emails and implement systems for sending numerous messages at once. This gives bulk emails structure. A private SMTP server might enhance your organizational framework for mass emailing if you oversee a newsletter or promotional emails.
  • Improves email deliverability: Deliverability of secure and efficient emails is made possible by SMTP servers, which examine the sender, recipient, and content of each message. You can use transactional emails to deliver data-driven, targeted, and personalized e-commerce messages. Messages transmitted from one SMTP server to another are particularly effective.
  • Technical support: Your SMTP service provider will offer professional assistance if you have any questions. They'll ensure that your mail account is set up correctly and address issues that may arise.
  • Allows for emailing from hardware: You can create a local server option by utilizing an SMTP address. Even though delivery can be slower, it offers greater flexibility and control.
  • Facilities with larger email volumes: If you use a local, dedicated SMTP server, you can send and receive more emails. For people that manage emails for business purposes, this can be helpful.
  • Prevents emails from going to spam: A newsletter or email marked as spam won't be delivered to the recipient. As a result, such emails are wasted and deleted before they're opened. With SMTP, your emails nearly always reach their intended recipients.

How to find an SMTP server

What is the SMTP server address for your email? The mail client or application you're using can set the address of an SMTP email server, which is often formatted as It can also be formatted in the following ways:


Your mail client's account or settings section is often where you may locate the address of your SMTP email server.

You must configure your mail program using the SMTP server if you plan to send emails. Follow the instructions below to determine your SMTP server address.

  • Select the command prompt by clicking on the Start menu and type RUN and hit ENTER.
  • Enter “ping SMTP server name” on the cmd line. Press “enter”

This command will communicate with your SMTP server through an IP Address.

What is the SMTP Server for Gmail?

Follow the instructions below to find the SMTP server for Gmail addresses.

  • SMTP server address:
  • SMTP port: 587 (With TLS)
  • SMTP username: Your Gmail account address
  • SMTP TLS/SSL required: Yes
  • SMTP password: Your Gmail password
  • SMTP port: 465 (With SSL)

You can use the same procedure to locate the SMTP email server address of any email, including Yahoo mail, Hotmail, iCloud, and so forth.

Wrapping up: SMTP servers

While SMTP servers aren't the only TCP/IP protocol you can use to send and receive emails, utilizing one can provide several benefits. From ensuring your bulk marketing emails are successfully delivered to preventing messages from being marked as spam, an SMTP server may be worth using.

Now that you know what an SMTP server is, it's time to find the right service provider. With Mailchimp, you can obtain the infrastructure necessary to send mass marketing campaigns via email. Plus, we provide 24/7 technical support to small and large businesses in all industries. You can also use email UTM medium codes to track the success of your campaigns. Our SMTP server has what you need to run productive email marketing campaigns.

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