Reading full email headers

Email headers determine where a message is sent, and records the specific path the message follows as it passes through each mail server.

You can easily read message headers by using an online tool such as https://toolbox.googleapps.com/apps/messageheader/ (English-only).

Or, if you'd like to read a message header yourself, follow the path of a message chronologically by reading from the bottom of the header, and working your way up.

Here's an example of a message header for an email sent from MrJones@emailprovider.com to MrSmith@gmail.com:

 

Delivered-To: MrSmith@gmail.com
Received: by 10.36.81.3 with SMTP id e3cs239nzb; Tue, 29 Mar 2005 15:11:47 -0800 (PST)
Return-Path:
Received: from mail.emailprovider.com (mail.emailprovider.com [111.111.11.111]) by mx.gmail.com with SMTP id h19si826631rnb.2005.03.29.15.11.46; Tue, 29 Mar 2005 15:11:47 -0800 (PST)
Message-ID: <20050329231145.62086.mail@mail.emailprovider.com>
Received: from [11.11.111.111] by mail.emailprovider.com via HTTP; Tue, 29 Mar 2005 15:11:45 PST
Date: Tue, 29 Mar 2005 15:11:45 -0800 (PST)
From: Mr Jones
Subject: Hello
To: Mr Smith

 

In the example, headers are added to the message three times:
  1. When Mr. Jones composes the email

     

    Date: Tue, 29 Mar 2005 15:11:45 -0800 (PST)
    From: Mr Jones
    Subject: Hello
    To: Mr Smith

     

  2. When the email is sent through the servers of Mr. Jones' email provider, mail.emailprovider.com

     

    Message-ID: <20050329231145.62086.mail@mail.emailprovider.com>
    Received: from [11.11.111.111] by mail.emailprovider.com via HTTP; Tue, 29 Mar 2005 15:11:45 PST

     

  3. When the message transfers from Mr. Jones' email provider to Mr. Smith's Gmail address

     

    Delivered-To: MrSmith@gmail.com
    Received: by 10.36.81.3 with SMTP id e3cs239nzb;Tue, 29 Mar 2005 15:11:47 -0800 (PST)
    Return-Path: MrJones@emailprovider.com
    Received: from mail.emailprovider.com (mail.emailprovider.com [111.111.11.111]) by mx.gmail.com with SMTP id h19si826631rnb; Tue, 29 Mar 2005 15:11:47 -0800 (PST)

     

Below is a description of each section of the email header:

Delivered-To: MrSmith@gmail.com

 

The email address the message will be delivered to.
Received: by 10.36.81.3 with SMTP id e3cs239nzb;
Tue, 29 Mar 2005 15:11:47 -0800 (PST)

 

The time the message reached Gmail's servers.
Return-Path:
The address from which the message was sent.
Received: from mail.emailprovider.com
(mail.emailprovider.com [111.111.11.111])
by mx.gmail.com with SMTP id h19si826631rnb.2005.03.29.15.11.46;
Tue, 29 Mar 2005 15:11:47 -0800 (PST)
The message was received from mail.emailprovider.com, by a Gmail server on March 29, 2005 at approximately 3 pm.
Message-ID: 20050329231145.62086.mail@mail.emailprovider.com
A unique number assigned by mail.emailprovider.com to identify the message.
Received: from [11.11.111.111] by mail.emailprovider.com via HTTP;
Tue, 29 Mar 2005 15:11:45 PST
Mr. Jones used an email composition program to write the message, and it was then received by the email servers of mail.emailprovider.com.
Date: Tue, 29 Mar 2005 15:11:45 -0800 (PST)
From: Mr Jones
Subject: Hello
To: Mr Smith
The date, sender, subject, and destination -- Mr. Jones entered this information (except for the date) when he composed the email.