Received from mail header

The Received header in an email message!

The Received header is a standard header in email messages that records the path the message took as it was transmitted from the sender to the recipient. It's a way to track the message's journey through the email infrastructure.

Here's a breakdown of the typical format of a Received header:

Received: from [sender's IP address] ([sender's domain name]) by [recipient's mail server] ([recipient's mail server's IP address]) with [transport protocol] id [unique message ID] for <[recipient's email address]>; [timestamp]

Let's break it down:

  1. from [sender's IP address] ([sender's domain name]): This part shows the IP address and domain name of the sender's mail server.
  2. by [recipient's mail server] ([recipient's mail server's IP address]): This part shows the IP address and domain name of the recipient's mail server.
  3. [transport protocol]: This part indicates the transport protocol used to deliver the message, such as SMTP (Simple Mail Transfer Protocol) or ESMTP (Extended SMTP).
  4. id [unique message ID]: This part is a unique identifier assigned to the message by the mail server.
  5. for <[recipient's email address]>: This part specifies the recipient's email address.
  6. [timestamp]: This part shows the timestamp when the message was received by the recipient's mail server.

Here's an example of a Received header:

Received: from mail.example.com ([192.0.2.1]) by mx.google.com with SMTP id i18-20020201T14:30:30Z for <[email protected]>; Thu, 01 Feb 2002 14:30:30 -0800

In this example, the message was sent from mail.example.com (the sender's mail server) to mx.google.com (the recipient's mail server) using the SMTP protocol. The message was received at 14:30:30 on February 1, 2002, and was intended for [email protected].