POP stands for Post Office Protocol. It is software which allows users to log onto a Mail Server and transmit or receive their mail from or to their own micro computer. This Client / Server ability means that users' computers do not have to be logged onto the internet for their email address to be valid. Users can compose or receive email on their micro computers whenever it is convenient.
When the internet first began, it used a Protocol called SMTP (Simple Mail Transport Protocol) to convey mail. This is fine as long as the host computer the mail is aimed at is switched on and connected to the internet. In the early days of computing most hosts were large mainframes which were always switched on and receiving mail. People had accounts on these mainframes and logged into them via serial terminals.
Since the advent of the personal computer (micro), users have had the processing power to handle email on their own computers. However, the nature of micro computers means that they do not always have to be switched on, they may also not be connected to the internet at all times as in the case of dial in networks. This disparity gave rise to POP. POP3 is the most popular implementation of POP and is aimed at 'desk top' email users.
The Opal Internet Service offers POP3 as part of its basic service package or as a separate service for those who already have access to the internet. This computer is always running and accepting mail. When users wish to read their mail they simply log into the POP (point of presence) and launch the email client (normally called Eudora). This client interrogates the mail server and if there is mail for that user it is sent to the client.
The client also allows the user to write and compose email while it is not logged into the network, this is in contrast to SMTP mail where you have to be 'online'. In the case of dial in networks this saves money as the telephone circuit is not in use. When the mail is completed, the user simply logs into the network and sends the mail to the server which forwards it on to the correct destination. It is not possible to do this with some internet providers who use SMTP mail for delivery. One of the potential disadvantages of SMTP delivery is that if you do not check your mail for a long period of time the Server will delete it.
Other advantages of POP mail are:
- The mail messages can be deleted from the server after they are downloaded.
- Users can reference old mail without having to log into the network as it is stored on their machines.
- If you have access to a mail client you can check your mail from ANYWHERE in the World.
