You have likely encountered SMTP, POP3, and IMAP abbreviations if you have utilized emails through your website or email software. These abbreviations refer to specific protocols that enable email sending and receiving. Understanding the differences between these protocols is essential to ensure that your email communication is efficient and reliable.
These protocols are vital for enterprise companies because they directly affect the emails they send customers and their ability to deliver them.
Although SMTP is a very technical issue and a bit difficult for engineers, it is essential to understand SMTP, POP3, and IMAP4 protocols.
What are SMTP, POP, and IMAP?
What is SMTP?
I started with the SMTP protocol because it differs from the other two protocols.
In this case, the Simple Mail Transfer Protocol (SMTP) is commonly used to send email from an email client (Thunderbird, Apple Mail, or Microsoft Outlook) to an email server.
It is also often used to forward emails from one email server to another. If the sender and recipient have different email providers, the ability to transfer feeds from one server to another is required.
SMTP uses port 25 as the standard, as specified in RFC 5321. You can also use ports 587 and 465. Second, it has now been introduced as the preferred port for secure SMTP (SMTPS), which is expected to be outdated. Even though some mail service providers still use it.
What is POP?
The Post Office Protocol or POP retrieves email messages from a mail server to a mail client over a TCP/IP connection. The latest version of this protocol is used worldwide, so it is currently called POP3.
As mentioned in RFC 1939, POP version 3 supports extensions and multiple authentication mechanisms. Authentication features are required to prevent malicious users from authorizing access to user messages.
Generally, POP3 processes messages from customers in this way:
- Connects to port 110 of the mail server (995 for SSL / TLS connections).
- Receives the email.
- Deletes copies of messages stored on the server.
- Disconnects from that server.
POP clients may be configured to allow the server to continue to save some copies of downloaded mail. The steps mentioned above are the most commonly used. Leaving copies on the server is usually an IMAP process.
What is IMAP?
Internet Message Access Protocol (IMAP) is the most advanced protocol in the current version of IMAP4. It allows users to group related messages and save them to folders that can be hierarchically organized later. It also tells when an email has been read, deleted, or forwarded. Allows users to search mailboxes.
The IMAP protocol generally works as follows:
- Connects to the mail server on port 143 (or 993 in the case of an SSL / TLS connection).
- Receives the email.
- The mail client application remains connected until you download the requested messages.
As mentioned earlier, the messages are not deleted from the server; they have more significant consequences.
How does SMTP work?
Now, if you understand a little better what SMTP means (hopefully), let’s go to what interests you: the email delivery or the “deliverability.”
The SMTP server you use to send emails is associated with a specific IP address. ISPs use this IP address to verify the sender’s reputation, which is directly related to the delivery capacity.
Due to the nature of its services, SMTP servers configured by conventional email providers (Gmail, Yahoo, Outlook, etc.) are not adapted to handle the sending of bulk emails.
IP addresses are not monitored closely so that you can send emails from the same server as a spam sender. Therefore, you may fall into spam if you send bulk emails through conventional email providers, such as those previously mentioned.
Difference Between POP3 and IMAP
The most significant difference between the POP3 email protocol and the IMAP protocol is that the first protocol is not designed to receive and send the other. The primary purpose of developing such a mail protocol is to allow the user to manage email without always connecting; this is a tremendous advantage for users in most cases. However, there will be a disadvantage when the Internet or telephone connections are weak.
It lets us download the email with a stable Internet connection and check it when disconnected or out of range.
In contrast, the IMAP protocol allows connected and disconnected operating modes to leave email messages on the server until we delete them manually, allowing us to read them from other computers or mobile devices, such as tablets.
The major disadvantage of the IMAP email protocol is that it downloads and writes emails that we always have to stay connected to the Internet; this usually requires an additional cost, which may be economically high.
If you do not have an Internet connection when you need to read emails, if the messages are not on the computer or device, we cannot perform this operation because they are stored on the email server.