Modern e-mail clients offer a lot of useful features, however
from the electronic mail's point of view it is required that an
e-mail client is able to send and receive mail. Depending on the
mail server type and the quality of the internet-connection we can
distinguish several ways of how e-mail is handled:
Connect to the Internet, download messages, disconnect.
Read the incoming mail, compose replies to messages, but instead of
sending them out right away place them into the Outbox folder.
Connect to the Internet, send outgoing mail, eventually download
new incoming mail, disconnect.
This is characteristic to circumstances when there is no permanent
connection to the Internet, e.g. via a modem. In this case the POP3
protocol is mainly used, though IMAP4 is also no wonder here.
Connect to the server, download mail, disconnect.
Read the incoming mail, compose replies to messages and send them
This is common to permanent connection to the Internet. Both POP3
and IMAP4 protocols can be used to retrieve mail.
Permanent connection to the server.
All the mail is stored on the server and can be downloaded on
demand. The server will notify the user when new messages arrive on
In this case a broadband connection to the Internet (e.g. local
network) is required. The use of the IMAP4 protocol is also
Each of the methods described above has its advantages and
disadvantages. For instance, the first one is the most undemanding
to the quality of the Internet connection, but is bound to a PC as
all the mail is stored there. The third method allows accessing the
same account from different PCs, but it requires a broadband
connection to the Internet, it constantly uses server resources and
is therefore dependent on the server's capabilities and current