Sender: If the message is being sent to multiple users on a single host, then only
a single copy of the message needs to be sent to the host.
Protocol: Used to transfer a message from sender to receiver.
Receiver: Accepts incoming mail and distributes them to the relevant mailboxes.
Multipurpose Internet Mail Extensions
It provides solutions to the problems encountered with the use of SMTP
It also allows multiple independent parts of the message, attachments.
Each message is first divided up into MIME type fragments.
Hypertext Transfer Protocol
A key concept of HTTP is the URL, it is defined as 'A compact representation of the
location and access method for the resources available via the net.
Proxy: Acts as an intermediate system between the client and the server.
Gateway: Acts on behalf of the server and can be used in issues of security. It can also
convert non-HTTP protocols. e.g a request made to an FTP site, can be converted to HTTP format.
