Web Technologies - Old Questions

5.  Explain the SMTP with example.

Simple Mail Transfer Protocol (SMTP) is an Internet standard for electronic mail (email) transmission across Internet Protocol (IP) networks. SMTP (Simple Mail Transfer Protocol) is a TCP/IP protocol used in sending and receiving e-mail. However, since it is limited in its ability to queue messages at the receiving end, it is usually used with one of two other protocols, POP3 or IMAP, that let the user save messages in a server mailbox and download them periodically from the server. In other words, users typically use a program that uses SMTP for sending e-mail and either POP3 or IMAP for receiving e-mail. On Unix-based systems, send mail is the most widely-used SMTP server for e-mail. A commercial package, Send mail, includes a POP3 server. Microsoft Exchange includes an SMTP server and can also be set up to include POP3 support.

SMTP usually is implemented to operate over Internet port 25. An alternative to SMTP that is widely used in Europe is X.400. Many mail servers now support Extended Simple Mail Transfer Protocol (ESMTP), which allows multimedia files to be delivered as e-mail.

An SMTP server performs two functions:

• Verifies proper configuration and grants permission to a computer attempting to send a message.
• Sends an outgoing message to a predefined destination and tracks the successful delivery of the message. If it is not deliverable, a message is sent back to the sender. All SMTP servers use their own code which identifies them. For instance, if you are using Hotmail to send e-mail. You would need to configure a mail client, such as Outlook Express with the following code: smtp.hotmail.com