Understanding SMTP is an uphill task if you are only starting to question how emails work. The world of email is firmly intertwined with ours, given how important email is in today’s highly digitalized world. This guide will serve as a solid introduction to SMTP and demystify how emails are sent.
Simple Mail Transfer Protocol, or SMTP for short, is an application used by servers to move emails on or across networks. It works together with a Mail Transfer Agent (MTA) to ensure emails are delivered to the right inboxes. It employs a process called the store and forwards to achieve this.
An SMTP server has one or several addresses, defined by the mail client, and indicated as smtp.serveraddress.com. In the case of the popular Gmail, the server host is smtp.gmail.com. To learn about your SMTP email server, go to your account settings of the mail client you are using.
After you click send on your email, it goes to the SMTP server for processing. It chooses the server that will receive your email, a process called Simple Mail Transfer Protocol relay. The receiver’s service provider will then download the email and hold it within the receiver’s inbox. The whole process is quick and efficient.
Is an SMTP server unique?
An SMTP server shares the same characteristics as a normal server. That means it processes data and forwards it to another. The only difference is that it is configured to process- send, receive and relay- emails alone. An STMP server does not have to run on a machine. Rather, it is an always-on application that is always primed to carry out its function.
Importance of an SMTP server
An SMTP server makes sending and receiving emails possible. It receives the email and turns it into text, stringed together with code words and numbers that identify each section and its purpose. The SMTP provides the language while the server software deciphers it.
The server also has a security function. It verifies that outgoing messages emanate from an active verified account. This is among the measures that protect your inbox from harmful emails. It will additionally return the email back to the sender’s SMTP server if it is not delivered. The sender receives a message that they have input the wrong email address, or have been blocked from sending emails to the receiving server.
There is an abundance of SMTP server providers ensuring that the huge market demand is met. In fulfilling this role, they:
- Provide a secure environment for sending and receiving email
- Offer dedicated IP addresses and flexible SMTP setups
- Provide software with an easy-to-use interface
- Offer email solutions that are fast and adaptable, and that integrate easily with your CRM
- Provide analytics to help you visualize your email in numbers.
How a Server Works
So what exactly happens in the SMTP server when you send an email?
Your mail client reaches your receiver’s server, using the port (the most popular port used between servers. Mail clients prefer to use submission ports)
Your mail client communicates with the receiving server first to verify that the authentication credentials are legitimate. Once the check passes, the message information (IP address, recipient, message body) is relayed.
SMTP server reviews the information it received and goes through the previous step with the receiver’s server.
The receiver’s server verifies the sender and recipient addresses. It reviews the sending domain for any likely DNS issues such as failed DKIM standards. If no issues are picked up, the receiver’s server will fetch the email through POP3 or IMAP and deliver it to its intended inbox.
The steps, in summary, are verification of the sender, granting permission for the process, and delivery.
SMTP is only able to relay text. Fonts, graphics, and attachments are not supported. For these, there are the Multipurpose Internet Mail Extensions which encode all other non-text input into plain text. Thereafter, it can be transferred by the SMTP.
Free vs Paid SMTP servers
The proliferation of email as a service means some free players have entered the market. These open-source servers are good for basic use, but they offer inadequate resources to make them suitable for corporate use. They put a cap on the number of emails you can send or receive daily or monthly. For businesses, a paid Simple Mail Transfer Protocol service that can receive thousands of bulk emails is recommended. Most providers offer free trials for their offerings, giving you the chance to sample an SMTP server at relatively low risk and charge. Look for a provider that supports scalability as that will allow your business to grow without interruption.
Do you need to set up your SMTP server?
No setup is required, so anyone with basic computing knowledge can use one. You only need to pass authentication with a designated username and password. There are different ports available depending on the level of encryption desired. 25,587 and 2525 are ideal for TSL encryption, but for SSL encryption, port 465 is preferred.
Inbuilt vs external SMTP servers
Having your own SMTP server has its distinct merits. It allows you to send bulk emails in a short time with a lower bounce rate, and you will have a more professional address. Additionally, you will have access to more data, which you can view for every account you have. However, these merits can be enjoyed with a Simple Mail Transfer Protocol service without the limitations of speed and performance that are common with servers provided by a web hosting provider. Additionally, the latter is superior when it comes to speed and deliverability.