How microsoft outlook sends mails

Microsoft Outlook uses a combination of technologies to send emails. Here's a high-level overview of the process:

  1. Composition: When you compose an email in Outlook, the email client creates a message in a format called Multipurpose Internet Mail Extensions (MIME). The message includes the sender's email address, recipient's email address, subject, body, and any attachments.
  2. SMTP (Simple Mail Transfer Protocol): Outlook uses the SMTP protocol to send the email to a mail server. SMTP is a protocol that allows email clients to send emails to a mail server, which then forwards the email to the recipient's mail server.
  3. Mail Server: The mail server is responsible for receiving the email from Outlook and storing it in a queue. The mail server is typically a Microsoft Exchange Server or a third-party mail server like Gmail or Yahoo.
  4. MTA (Mail Transfer Agent): The mail server uses a Mail Transfer Agent (MTA) to forward the email to the recipient's mail server. The MTA is responsible for routing the email to the correct mail server based on the recipient's email address.
  5. Recipient's Mail Server: The recipient's mail server receives the email from the MTA and stores it in a queue.
  6. POP3 (Post Office Protocol version 3) or IMAP (Internet Message Access Protocol): The recipient's mail server uses POP3 or IMAP to deliver the email to the recipient's email client, such as Outlook.
  7. Delivery: The email is delivered to the recipient's email client, where it is stored in the inbox.

Here's a more detailed look at the process:

Outlook's SMTP Connection

When you send an email in Outlook, the client establishes an SMTP connection with the mail server. The SMTP connection is typically established using the following steps:

  1. Outlook sends an EHLO (Extended Hello) command to the mail server, which identifies the client and requests a list of supported SMTP commands.
  2. The mail server responds with a list of supported SMTP commands and its own EHLO response.
  3. Outlook sends a MAIL FROM command to specify the sender's email address.
  4. Outlook sends a RCPT TO command to specify the recipient's email address.
  5. Outlook sends the email message using the DATA command.
  6. The mail server stores the email in a queue and forwards it to the recipient's mail server using the MTA.

Mail Server's MTA Connection

The mail server's MTA connection is responsible for routing the email to the correct mail server based on the recipient's email address. The MTA connection is typically established using the following steps:

  1. The mail server's MTA sends an EHLO command to the recipient's mail server, which identifies the mail server and requests a list of supported SMTP commands.
  2. The recipient's mail server responds with a list of supported SMTP commands and its own EHLO response.
  3. The mail server's MTA sends a MAIL FROM command to specify the sender's email address.
  4. The mail server's MTA sends a RCPT TO command to specify the recipient's email address.
  5. The mail server's MTA sends the email message using the DATA command.
  6. The recipient's mail server stores the email in a queue and delivers it to the recipient's email client using POP3 or IMAP.

POP3 or IMAP Connection

The recipient's mail server uses POP3 or IMAP to deliver the email to the recipient's email client. The POP3 or IMAP connection is typically established using the following steps:

  1. The recipient's mail server sends an EHLO command to the email client, which identifies the client and requests a list of supported POP3 or IMAP commands.
  2. The email client responds with a list of supported POP3 or IMAP commands and its own EHLO response.
  3. The recipient's mail server sends a USER command to specify the recipient's email address.
  4. The recipient's mail server sends a PASS command to specify the recipient's email password.
  5. The recipient's mail server sends the email message using the RETR command.
  6. The email client stores the email in the inbox.