Simpal Mail Transfer Protocol
Simpal Mail Transfer Protocol
SMTP:- The SMTP (Simple Mail Transfer Protocol) protocol is used by the Mail Transfer Agent (MTA) to deliver your email to the recipient’s mail server. The SMTP protocol can only be used to send emails, not to receive them. SMTP works like a post assistant, handling the sending of emails from an email client to an email server. It receives outgoing mail messages from users and routes them to the mail recipients they are intended for. Most e-mail systems that send mail over the Internet use SMTP to send messages from one server to another; the messages can then be retrieved with an e-mail client using either POP or IMAP. It is a text based protocol in which message text is specified along with the recipients of the message. Simple Mail Transfer Protocol is a ‘push’ protocol and it cannot be used to ‘pull’ the messages from the server. A procedure of requests and responses is used to send the message between the client and the server. An end user’s e-mail client can act as an SMTP client, which is used to initiate or establish a TCP connection to the port 25 of the server. SMTP is used to send the message from the mail client to the mail server and an e-mail client using the POP or IMAP is used to retrieve the message from the server.
An SMTP server performs the following two functions :· It verifies the configuration and grants the permission to a computer that is making an attempt to send a message. It sends the message to the specified destination and tracks it to see whether it’s delivered successfully or not. If it’s not delivered successfully then an error message is send to the sender.
· There’s one limitation to SMTP and it’s the inability to authenticate the senders and this results in e-mail spamming. The enhanced version of SMTP also exists and it’s called as Extended SMTP (ESMTP). ESMTP is used to send the e-mails that include graphics and other attachments.
SMTP clients and servers have two main components:User Agents – Prepares the message, encloses it in an envelope.
Mail Transfer Agent (MTA) – Transfers the mail across the internet
