How mail works on internet

Mail, also known as electronic mail or email, is a system for sending and receiving messages over the internet. Here's a simplified overview of how it works:

Components:

  1. Mail User Agent (MUA): This is the email client software that you use to compose, send, and receive emails. Examples include Microsoft Outlook, Mozilla Thunderbird, and Gmail's web interface.
  2. Mail Transfer Agent (MTA): This is the software that transfers emails between mail servers. Examples include Sendmail, Postfix, and Exim.
  3. Mail Server: This is the server that stores and manages email accounts. Examples include Microsoft Exchange, IBM Domino, and Google's Gmail servers.
  4. Internet Service Provider (ISP): This is the company that provides you with internet access.

The Process:

  1. Composition: You compose an email using your MUA, specifying the recipient's email address, subject, and message body.
  2. Sending: Your MUA sends the email to your ISP's mail server (MTA) using the Simple Mail Transfer Protocol (SMTP).
  3. Relaying: The ISP's mail server (MTA) relays the email to the recipient's ISP's mail server (MTA) using SMTP.
  4. Delivery: The recipient's ISP's mail server (MTA) delivers the email to the recipient's mail server (MTA) using SMTP.
  5. Storage: The recipient's mail server (MTA) stores the email in the recipient's email account.
  6. Retrieval: The recipient uses their MUA to retrieve the email from their mail server (MTA) using the Post Office Protocol (POP) or Internet Message Access Protocol (IMAP).

SMTP:

SMTP is a protocol used for sending and receiving emails between mail servers. It works as follows:

  1. Connection: The sender's MUA establishes a connection with the sender's ISP's mail server (MTA) using SMTP.
  2. Authentication: The sender's MUA authenticates with the sender's ISP's mail server (MTA) using a username and password.
  3. Message: The sender's MUA sends the email message to the sender's ISP's mail server (MTA) using SMTP.
  4. Relaying: The sender's ISP's mail server (MTA) relays the email to the recipient's ISP's mail server (MTA) using SMTP.
  5. Delivery: The recipient's ISP's mail server (MTA) delivers the email to the recipient's mail server (MTA) using SMTP.

POP and IMAP:

POP and IMAP are protocols used for retrieving emails from a mail server. They work as follows:

  1. Connection: The recipient's MUA establishes a connection with the recipient's mail server (MTA) using POP or IMAP.
  2. Authentication: The recipient's MUA authenticates with the recipient's mail server (MTA) using a username and password.
  3. Retrieval: The recipient's MUA retrieves the email messages from the recipient's mail server (MTA) using POP or IMAP.
  4. Download: The recipient's MUA downloads the email messages to the recipient's local device.

In summary, email works by using a combination of protocols (SMTP, POP, and IMAP) and software (MUA, MTA, and mail server) to send and receive messages over the internet.