SMTP

SMTP-SIMPLE MAIL TRANSFER PROTOCOL
This is an application layer protocol.It belongs to the model TCP\IP.As the name implies this transfers the message from the sender mail servers to the recipients server. This is its duty or operation. This always uses a socket called as TCP socket on port 25.This port socket is used to transfer mails from client to the server.Actually this email is stored temporarily on a local.Then only they are transferred to the recipients server.The client interacts with the local SMTP to deliver a message. A queue is maintained for proper input and output operations.this is its mode of performance.