What is SMTP, and how does it work?

person holding black iphone 5

The world knows email as one of the most used communication methods for businesses and consumers today. While using it is simple on the front-end, the back-end is significantly more complex. Behind the scenes, your message must somehow make it from you to any number of recipients you choose. The process itself is known as SMTP.


Knowing the ins and outs of this protocol becomes crucial if faced with deciding between hosting a personal server or using a third-party service. However, before we provide the benefits and drawbacks of each, a clear definition of the protocol itself is needed.


SMTP, Defined


SMTP is an acronym standing for Simple Mail Transfer Protocol. As an email protocol, SMTP is at the core of the email sending process on the internet. Similar to other protocols, SMTP includes a set of rules that determine how email clients and accounts are exchanging messages.


The SMTP protocol is only one of the widely used sets of rules, accompanied by POP (Post Office Protocol) and IMAP (Internet Message Access Protocol). However, SMTP is the only protocol dedicated to email sending. Therefore, commonly used clients such as Outlook, Apple Mail, Yahoo, and Gmail rely on SMTP to send messages.


Employing SMTP hosting then becomes a major decision for website owners looking for a solution to reliably send emails from their website to their visitors.


The Difference Between SMTP and Other Email Protocols


Compared to email protocols POP and IMAP, SMTP has the unique task of pushing an email. POP and IMAP protocols transfer an email by pulling it for the recipient from their mail server. Therefore, POP and IMAP are more limited in functionality since communication can only occur within their network.


SMTP In Action


Now that we have defined what SMTP is, you are likely wondering how it works. To explain this process, let’s first consider how sending an email works. In the presence of an established SMTP server, email clients establish a connection that enables communication to and from it. Therefore, after a sender hits “send” on their composed email, the email client will open the connection to the server.


Afterwards, the SMTP client will convey commands to the server, telling it to transfer relevant data such as the addresses of the email sender and recipient and the message contained in the email. Next, the data will encounter a Mail Transfer or Message Transfer Agent. The Mail Transfer Agent is responsible for receiving incoming emails and forwarding the contents to the right user in a verification process. If the information matches, the email is sent right away. However, if the information does not match, the Domain Name System (also known as a DNS) will be called upon to identify the recipient’s domain and redirect it to the right server.


Running A Server vs. Relying On A Third Party


SMTP is a make or break for website owners to communicate with visitors. Therefore, the question for website owners will be, should a personal server be set up, or is a third-party service more advantageous? Unfortunately, there is no single correct answer. Rather, the decision is solely dependent on the needs and resources of the individual.

A Personal SMTP Server


Consider first the benefits. By hosting a server, website owners will not face any limits on volume, a crucial feature for large websites. At present, some email service providers will cap the number of daily emails that one can send. Additionally, by having a dedicated server, the list of people you email remains private to you and you alone, ensuring high levels of data privacy.


In contrast, time, money, effort and other resources are major drawbacks. When you have a dedicated server, you must constantly monitor it to ensure that everything is up and running properly. Therefore, if you or your team don’t have the skills or availability to do so, you may need to hire outside help.

A Third-Party SMTP Host


One benefit becomes evident in reviewing the drawbacks of a personal SMTP Server. First and foremost, a third-party service requires less effort for the website owner. Since a provider offers these services, there is no need for technical knowledge or time spent troubleshooting. Instead, website owners can call on a team of experienced customer service representatives when they need support if an issue arises. Additionally, a secondary benefit is apparent in security. Most providers will offer multiple backup options to ensure emails are safe even if a server goes down.


The main drawback of using a third party is becoming reliant on your provider. Therefore, those considering a provider are encouraged to do some research to ensure that their provider is reliable and has a significant amount of relevant experience. Going down this route will also put users at the discretion of the provider’s terms and conditions.

SND Team

We are a team of writers passionate about entrepreneurship and innovation. We cover anything else that our readers may find interesting. This includes trending news, lifestyle and finance topics, consumer guides, and much more.


Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.