TCP/IP mail
Email is one of the most important applications of TCP/IP.
You won't be using...
When you write an email, you won't be using TCP/IP.
When you write an email, you are using an email program, such as Lotus Notes, Microsoft Outlook, or Netscape Communicator.
The mail program will use...
Your email program uses a different TCP/IP protocol:
Use SMTP To send mail
Use POP to download mail from the mail server
Use IMAP to connect to the mail server
SMTP - Simple Mail Transfer Protocol
The SMTP protocol is used to transfer email. SMTP is responsible for sending mail to another computer.
Normally, mail will be sent to one mail server (SMTP server), then to another server (or servers), and then finally to its destination.
SMTP can also transmit plain text, but cannot transmit binary data such as pictures, sounds, or movies.
SMTP uses the MIME protocol to send binary data over a TCP/IP network. The MIME protocol converts binary data into plain text.
POP - Post Office Protocol
The POP protocol is used by mail programs to retrieve mail from the mail server.
If your mail program uses POP, then once it connects to the mail server, all your mail will be downloaded to the mail program (or called the mail client).
IMAP - Internet Message Access Protocol
Similar to POP, the IMAP protocol is also used by email programs.
The main difference between the IMAP protocol and the POP protocol is that if IMAP is connected to a mail server, it will not automatically download the mail to the mail program.
IMAP gives you the ability to view emails on the mail server before downloading them. With IMAP, you can choose to download these messages or simply delete them. Let's say you need to access your mail server from a different location, but only want to download your mail when you get back to the office. IMAP can be useful in this situation.
