How is mail sent via internet

Sending mail via the internet is a process called "electronic mail" or "email." Here's a step-by-step explanation of how it works:

Composition

  1. You compose an email using a device with an internet connection, such as a computer, smartphone, or tablet.
  2. You enter the recipient's email address, a subject line, and a message body.
  3. You may also attach files, such as documents, images, or videos, to the email.

Transmission

  1. When you click the "Send" button, your device sends the email to your internet service provider's (ISP) mail server.
  2. The ISP's mail server is responsible for routing the email to its final destination.
  3. The email is transmitted over the internet using a protocol called Simple Mail Transfer Protocol (SMTP).

Routing

  1. The ISP's mail server looks up the recipient's email address in a database to determine the best route to send the email.
  2. The email is forwarded to the recipient's ISP's mail server, which is responsible for delivering the email to the recipient's inbox.
  3. The recipient's ISP's mail server may perform additional checks, such as spam filtering or virus scanning, before delivering the email to the recipient's inbox.

Delivery

  1. The recipient's ISP's mail server delivers the email to the recipient's email client, such as Microsoft Outlook or Gmail.
  2. The email client retrieves the email from the mail server and displays it in the recipient's inbox.
  3. The recipient can then read, reply, or forward the email as needed.

Security

  1. To ensure the security and integrity of email transmission, various protocols and technologies are used, such as:
    • Transport Layer Security (TLS) or Secure Sockets Layer (SSL) to encrypt the email transmission.
    • Authentication, Authorization, and Accounting (AAA) protocols to verify the identity of the sender and recipient.
    • Spam filtering and virus scanning to detect and block malicious emails.

Key Players

  1. Mail User Agent (MUA): The software or application used to compose, send, and receive emails, such as Microsoft Outlook or Gmail.
  2. Mail Transfer Agent (MTA): The software or server that routes emails between mail servers, such as Sendmail or Postfix.
  3. Mail Delivery Agent (MDA): The software or server that delivers emails to the recipient's email client, such as Microsoft Exchange or Dovecot.

In summary, sending mail via the internet involves composing an email, transmitting it to the recipient's ISP's mail server, routing it through the internet, and delivering it to the recipient's email client.