What is POP

POP, or Post Office Protocol, is a computer network and Internet standard protocol; it is one of the most commonly used protocols for receiving email on email clients. The following article will introduce POP (Post Office Protocol) in detail. I hope it will be helpful to you.

Basic knowledge of POP

POP (Post Office Protocol) can be sent from a remote mail server Extracts and retrieves email for host access; it is an application layer protocol in the OSI model that provides end users with the ability to obtain and receive email.

POP is the main protocol behind email communication and it works by supporting email software clients that integrate POP to connect to remote email servers and download emails to the recipient's on the computer.

POP uses the TCP/IP protocol stack for network connectivity and the SMTP protocol for end-to-end email communication, where POP pushes mail and SMTP to the server.

POP has two different versions: POP2 and POP3, let’s introduce these two versions below:

POP2

POP2 is an early standard for POP that became a standard in the mid-1980s and can only receive email and requires SMTP to send email.

POP3

POP3 is the latest standard for POP. It can be used with SMTP to send and receive emails; it can also be used without SMTP use together.

POP3 is a client/server protocol that allows users to upload or download emails on their local computer, while Internet servers receive and save emails for users until they until the email is downloaded. POP3 will delete the email immediately after the user downloads it, however, some implementations allow the user or administrator to save the email for a specified period of time.

By default, the POP3 protocol works on two ports:

Port 110: This is the default POP3 non-encrypted port

Port 995: If you want to connect securely using POP3, this is the port you need to use

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