POP stands for Post Office protocol used in application layer of OSI model, Primary purpose of this protocol is to retrieve e-mail from the main servers, Alternative to POP protocol which is new also is IMAP i.e. Internet Message Access Protocol. POP protocol has two version POP2 and POP3. In mid of 80’s this protocol became a standard and require SMTP to send messages while POP3 can work with or without SMTP. This protocol is a type of computer networking and internet standard protocol and have an ability to fetch and receive email.
POP is the primary protocol behind email communication. It works to support email software client that integrates POP for connecting to the remote email server so that it can download email messages to the recipient’s computer machine. This protocol use TCP/IP protocol stack for network connection and work with SMTP to done end-to-end communication, POP pull message and SMTP push them on server. POP version 3 i.e. POP3 is commonly used in most email/server communication architecture.
POP3 is the oldest and best known internet message access protocol. Purpose to design this protocol is to support offline email processing so that remote email client periodically download message from this server to the user’s PC and once the message are delivered to the client they are deleted from the email server. This protocol encompasses of email systems so that later user can retrieve email from the central location where all the email are stored. This allow user to have their mailboxes on a server with domain name. Protocol is providing a simple, standardize way for users to access mailboxes and download messages to their own systems.
One of the main advantage of this protocol is once the message is delivered to the client PC then that message can be read whether user connected to internet or not. Another advantage is, it is very popular email protocol and support all email clients. There is no size limit on the sending and receiving email. Opening attachment is very quick because its already stored on you PC. There is no advertising to your personal mails until and unless you are using Adware email reader like Eudora Freeware.