Email Protocols – POP3, SMTP and IMAP

The tutorial provides detailed information about what is POP3 and the default ports for them. You shall also come across most commonly used Email protocols on the internet – POP3, IMAP and SMTP.

What is POP3?

The standard mail protocol Post Office Protocol version 3 (POP3) is used to receive emails from a remote server to a local email client. You can download emails on your local computer and can read them offline using POP3. POP3 will store your mails locally and delete them from the server once it is downloaded. However, you get a check mark the option “Leave a copy on server”, a copy of email remains on server and you can configure the pop account on another machine.

Otherwise, POP3 by default deletes the mails from the server, and helps to reduce the space that your email account uses on your web server. POP3 protocol assumes that your email is being accessed only from one application and may not be an ideal option if you want to manage your mails across different locations.

Default POP3 Ports

POP3 protocol works on two ports:

  • Port 110– Default POP3 non-encrypted port
  • Port 995– Used to connect using POP3 securely

What is IMAP?

An alternative protocol is Internet Message Access Protocol (IMAP) which is used for accessing email on the remote web server from local client. IMAP can be thought of as a remote file server. It gives the user more capabilities by retaining email on the server and organizing it in folders. IMAP allows simultaneous access by multiple clients. So, it is quite suitable for you if you’re going to access your email from different devices & location.

Default IMAP Ports

IMAP protocol works on two ports:

  • Port 143– Default IMAP non-encrypted port
  • Port 993– Used to connect IMAP securely

IMAP and POP3 are the most common Internet mail protocols used for retrieving emails and are supported by all modern email clients and web servers

What is SMTP?

Simple Mail Transfer Protocol (SMTP) is the standard protocol for transferring e-mail across the Internet by using the “Store & Forward” process.

Default SMTP Ports

The SMTP protocol works on three ports:

Port 25 – Default SMTP non-encrypted port

Port 26 – Opened on all servers

Port 465 – Used to send messages securely using SMTP

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