Answer:
Exchange of email is mentioned below:
1) A user composes a message and sends the email, Sent Email messages and files are uploaded in an outgoing mail server via Simple Mail Transfer Protocol(SMTP).
2) All outgoing messages remain in outgoing mail queue until the SMTP server communicates with the DNS (Domain Name Server).
3) When the SMTP server locates the recipient's email server, Then messages or file attachments will be transferred else; the sender will receive a "Mail Failure" notification.
4) The recipient email client will download all the messages and attachments that were being sent to him by the sender, and it displays a notification of received email in an inbox.