POP3 Protocol
POP3 Protocol
POP3 is an internet-based standard for retrieval of e-mail by a user from an e-mail server. POP stands for Post Office Protocol. The “3” means it is the third revision of the standard; POP1 and POP2 were made out of date by POP3, which has been popular for many years now. POP3 is a standard mail protocol used to receive emails from a remote server to a local email client. POP3 allows you to download email messages on your local computer and read them even when you are offline. POP3 makes it easy for anyone to check their email from any computer in the world. Much like the physical version of a post office clerk, POP3 receives and holds email for an individual until they pick it up. And, much as the post office does not make copies of the mail it receives, when an individual downloaded email from the server into their email program (local PC), there were no more copies of the email on the server; POP automatically deleted them. POP3 is a client/server protocol in which e-mail is received and held for you by your Internet server. Periodically, you (or your client e-mail receiver) check your mail-box on the server and download any mail using POP3. POP3 is designed to delete mail on the server as soon as the user has downloaded it. However, some implementations allow users or an administrator to specify that mail be saved for some period of time. POP can be thought of as a “store-and-forward” service. POP3 uses TCP/IP port 110 as like SMTP uses port number 25. The design of POP3 and its procedures supports users to retrieve e-mail when connected and then to view and manipulate the retrieved messages without needing to stay connected. Although most clients have an option to leave mail on server, e-mail clients using POP3 generally connect, retrieve all messages, store them on the user’s PC as new messages, delete them from the server, and then disconnect. Below figure shows the process of sending mail (SMTP) and receiving mail (POP3).
Advantages of POP3· Email is available when you are offline
· Email is not stored on the server, so your disk usage on the server is less
· Just about any email client (software) supports POP3
