Because of SMTP, a UNIX machine can send mail to a PC or Macintosh computer and vice versa. A client program enables the user to interact with a server in order to access information and services on the server computer. The client application is the interface which lets a user read, reply to, forward, compose and send new messages. An electronic mail message is not limited to text. Other types of files can be added to mail messages as attachments.
Attachments can be binary files such as a word processed document, a spreadsheet or a graphic image.
A standard called MIME, Multipurpose Internet Mail Extensions, allows for non-text files to be encoded on the sending computer and decoded on the receiving computer. SMTP is the protocol that ensures this system of sending and receiving information works smoothly. A client program is used to read mail, reply to mail and send new messages. Inc. This material may be quoted or reproduced provided appropriate credit is given and copyright notice is retained.