Email Headers

• Standard Headers

  • From, showing the sender's email address

  • To, showing the recipient's email address

  • Date, showing the date when the email was sent.

• Optional Headers

  • Received, showing various information about the intermediary servers and the date when the message was processed

  • Reply-To, showing a reply address

  • Delivered-To displays the recipient’s name and address, as well as other addresses present in the CC and BCC

  • From: IP address/other details about sender

  • subject showing the message's subject

  • message-ID, showing a unique identification for the message

  • message body, containing the message, separated from the header by a line break

  • Return-Path: return address in case of email failure

  • Content-Type field indicates whether the format of an email was HTML, TXT, or any other option

  • Received-SPF: sender verification

  • Authentication-Results: ID of authentication performing server

  • DKIM Signature: details of the sender, message, and the public key which is required to perform message authentication

• Custom X-Headers

  • X-Received: non-standard headers added by some email providers

• Header Lists/Guides

  • IANA Email Message Headers List

  • Email Header Quick Reference Guide

  • Email Header Guide

  • Email headers: What they are & how to read them

  • Email Header Analysis and its application in Email Forensics